Rule Changes Notice. Number 1 to the 2010 Edition

Transcription

1 COMMON STRUCTURAL RULES FOR BULK CARRIERS JULY 2010 Rule Changes Notice Number 1 to the 2010 Edition Notes: (1) These Rule Changes enter into force on 1st July (2) This Rule Change Notice should be read in conjunction with the July 2010 consolidated edition of Bulk Carriers CSR. Copyright in these Common Structural Rules for Bulk Carriers is owned by: American Bureau of Shipping Bureau Veritas China Classification Society Det Norske Veritas Germanischer Lloyd Korean Register of Shipping Lloyd's Register Nippon Kaiji Kyokai Registro Italiano Navale Russian Maritime Register of Shipping Copyright 2008 The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as the IACS Members. The IACS Members, individually and collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant IACS Member entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

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3 For technical background for Rule Changes in this present document, reference is made to separate document Technical Background for Rule Changes Proposal. Rule Change Notice 1 July 2010 edition i / vi

4 List of changes CHAPTER 1 GENERAL PRINCIPLES... 1 Section 4 Symbols and Definitions Definitions Single Side Skin and Double Side Skin construction Single side skin construction Double side skin construction Bilge Bilge plating... 1 CHAPTER 2 GENERAL ARRANGEMENT DESIGN... 3 Section 1 Subdivision Arrangement Collision bulkhead Arrangement of collision bulkhead After peak, machinery space bulkheads and stern tubes General General Section 2 Compartment Arrangement Cofferdams Cofferdam arrangement Minimum Bow Height General Section 3 Access Arrangement Technical provisions for means of access Access to double side skin tanks of double side skin construction Access to vertical structures of cargo holds of single side skin construction Access to vertical structures of cargo holds of double side skin construction Access to top side ballast tanks... 5 CHAPTER 3 STRUCTURAL DESIGN PRINCIPLES... 6 Section 3 Corrosion Additions Corrosion additions Corrosion addition determination Corrosion additions for steel... 6 ii / vi Rule Change Notice 1 July 2010 edition

5 Section 5 Corrosion Protection General Protection of seawater ballast tanks and void double side skin spaces Protection of cargo hold space Side areas to be coated Transverse bulkhead areas to be coated... 7 Section 6 Structural Arrangement Principles Application General principles Connections with higher tensile steel Connections with higher tensile steel Ordinary stiffener Profile of stiffeners Stiffener profile with a bulb section Primary supporting members Stiffening arrangement Effective breadth of primary supporting member General Double bottom General Height of double bottom Single side structure in cargo hold area Deck structure General arrangement Deck between hatches Bulkhead structure Non-tight bulkheads Non-tight bulkheads not acting as pillars CHAPTER 4 DESIGN LOADS Section 5 External Pressures Pressure in bow area Bow flare area pressure Section 6 Internal Pressures and Forces Testing lateral pressure Still water pressure CHAPTER 5 HULL GIRDER STRENGTH Rule Change Notice 1 July 2010 edition iii / vi

6 Section 1 Yielding Check Hull girder stresses Shear stresses Simplified calculation of shear stresses induced by vertical shear forces CHAPTER 6 HULL SCANTLINGS Section 1 Plating Strength check of plating subjected to lateral pressure Plating thickness Net thickness of the corrugations of transverse vertically corrugated watertight bulkheads separating cargo holds for flooded conditions Section 2 Ordinary stiffeners Yielding check Scantlings of transverse vertically corrugated watertight bulkheads separating cargo holds for flooded conditions Bending capacity and shear capacity of the corrugations of transverse vertically corrugated watertight bulkheads separating cargo holds Web stiffeners of primary supporting members Net scantlings Connection ends of web stiffeners Section 3 Buckling and ultimate strength of ordinary stiffeners and stiffened panels Buckling criteria of partial and total panels Ultimate strength in lateral buckling mode Evaluation of the bending stress σ b Equivalent criteria for longitudinal and transverse ordinary stiffeners not subjected to lateral pressure Section 4 Primary supporting members General Flooding check of primary supporting members General Flooding check of primary supporting members Net section modulus and net shear sectional area under flooded conditions CHAPTER 7 DIRECT STRENGTH ANALYSIS Section 3 Detailed Stress Assessment Analysis model Areas to be refined CHAPTER 8 FATIGUE CHECK OF STRUCTURAL DETAILS iv / vi Rule Change Notice 1 July 2010 edition

7 Section 1 General Consideration General Subject members Appendix 1 Cross Sectional Properties for Torsion Example calculation for a single side hull cross section Notes CHAPTER 9 OTHER STRUCTURES Section 1 Fore Part Symbols General Application Arrangement Floors and bottom girders Solid floors Bottom girder Scantlings Plating Primary supporting members Deck primary supporting members Strengthening of flat bottom forward area Application Bottom plating Ordinary stiffeners Section 2 AFT PART Symbols Scantlings Primary supporting members Deck primary supporting members Section 3 Machinery Space Double bottom Arrangement Side bottom girders in way of machinery seatings Section 5 Hatch Covers Rule Change Notice 1 July 2010 edition v / vi

8 4. Load Model Load Point Sea pressures Other pressures CHAPTER 10 HULL OUTFITTING Section 1 Rudder and Manoeuvring Arrangement Rudder body, rudder bearings Strength of rudder body CHAPTER 11 CONSTRUCTION AND TESTING Section 2 Welding Types of welded connections Butt welding Welding of plates with different thicknesses Full penetration welds Application Section 3 Testing of Compartments Testing requirements General vi / vi Rule Change Notice 1 July 2010 edition

9 Chapter 1 General Principles Section 4 Symbols and Definitions 3. Definitions KC 1009 The following definitions are added: 3.21 Single Side Skin and Double Side Skin construction Single side skin construction A hold of single side skin construction is bounded by the side shell between the inner bottom plating or the hopper tank plating when fitted, and the deck plating or the topside tank plating when fitted Double side skin construction A hold of double side skin construction is bounded by a double side skin, including hopper tank and topside tank when fitted. KC 567 The following definition is added: 3.22 Bilge Bilge plating The bilge plating is the curved plating between the bottom shell and side shell. It is to be taken as follows: within the cylindrical part of the ship (see Fig.4): from the start of the curvature at the lower turn of bilge on the bottom to the end of the curvature at the upper turn of the bilge, outside the cylindrical part of the ship (see Fig.5): From the start of the curvature at the lower turn of the bilge on the bottom to the lesser of: a point on the side shell located 0.2D above the baseline/local centreline elevation. the end of the curvature at the upper turn of the bilge. Rule Change Notice 1 July 2010 edition 1 / 34

10 Figure 4: vertical extent of bilge plating within the cylindrical part of the hull Figure 5: vertical extent of bilge plating outside the cylindrical part of the hull Note: Figure 4 in Ch.1 Sec.4 [4.1.1] and its reference are to be changed into Figure 6. 2 / 34 Rule Change Notice 1 July 2010 edition

11 Chapter 2 General Arrangement Design Section 1 Subdivision Arrangement 2. Collision bulkhead 2.1 Arrangement of collision bulkhead KC 903 The current text is replaced by the following one: Ref. SOLAS Ch. II-1, Part B-2, Reg. 12 A collision bulkhead is to be fitted which is to be watertight up to the bulkhead deck. This bulkhead is to be located at a distance from the forward perpendicular FP LL of not less than 5 per cent of the length L LL of the ship 0.05L LL or 10 m, whichever is the less, and, except as may be permitted by the Society, not more than 8 per cent of L LL 0.08L LL or 0.05L LL +3 m, whichever is the greater. 3. After peak, machinery space bulkheads and stern tubes KC 798 The following titles are modified as follow: 3.1 General General The current text is replaced by the following one: Ref. SOLAS Ch. II-1, Part B, Reg. 11 An after peak bulkhead, and bulkheads dividing the machinery space from the cargo spaces forward and aft, are also to be fitted and made watertight up to the freeboard deck. The after peak bulkhead may, however, be stepped below the bulkhead deck, provided the degree of safety of the ship as regards subdivision is not thereby diminished. An aft peak bulkhead, enclosing the stern tube and rudder trunk in a watertight compartment, is to be provided. Where the shafting arrangements make enclosure of the stern tube in a watertight compartment impractical alternative arrangements will be specially considered. Rule Change Notice 1 July 2010 edition 3 / 34

12 3.1.2 The following requirements are added: The aft peak bulkhead may be stepped below the bulkhead deck, provided that the degree of safety of the ship as regards subdivision is not thereby diminished The aft peak bulkhead location on ships powered and/or controlled by equipment that does not require the fitting of a stern tube and/or rudder trunk will also be subject to special consideration. The aft peak bulkhead may terminate at the first deck above the summer load waterline, provided that this deck is made watertight to the stern or to a watertight transom floor. Section 2 Compartment Arrangement 2. Cofferdams 2.1 Cofferdam arrangement KC 793 This requirement is deleted Spaces intended for the carriage of flammable liquids are to be separated from accommodation and service spaces by means of a cofferdam. Void 5. Minimum Bow Height 5.1 General KC 1082 The reference number to ILLC is replaced by the following one: Ref. ILLC, as amended (Resolution MSC.143(77) 223(82) Reg. 39(1)) 4 / 34 Rule Change Notice 1 July 2010 edition

13 KC 1082 The definition of T 1 is replaced by the following one: T 1 : Draught at 85% of the depth for freeboard D 1 least moulded depth, in m The definition of D 1 is deleted: D 1 : Depth for freeboard, is the moulded depth amidship plus the freeboard deck thickness at side. The depth for freeboard in a ship having a rounded gunwale with a radius greater than 4% of the breadth (B) or having topsides of unusual form is the depth for freeboard of a ship having a midship section with vertical topsides and with the same round of beam and area of topside section equal to that provided by the actual midship section. Section 3 Access Arrangement 2 Technical provisions for means of access KC 1009 The following title is changed as follow: 2.8 Access to double side skin tanks in double side bulk carriers 2.8 Access to double side skin tanks of double side skin construction KC 1009 The following title is changed as follow: 2.9 Access to vertical structures of cargo holds in single side bulk carriers 2.9 Access to vertical structures of cargo holds of single side skin construction KC 1009 The following title is changed as follow: 2.10 Access to vertical structures of cargo holds in double side bulk carriers 2.10 Access to vertical structures of cargo holds of double side skin construction KC 1009 The following title is changed as follow: 2.11 Access to top side ballast tanks in single side bulk carriers 2.11 Access to top side ballast tanks Rule Change Notice 1 July 2010 edition 5 / 34

14 Chapter 3 Structural Design Principles Section 3 Corrosion Additions 1. Corrosion additions 1.2 Corrosion addition determination Corrosion additions for steel KC 773 The following text is to be added before the last paragraph: The corrosion addition of a longitudinal stiffener is determined according to the coordinate of the connection of the stiffener to the attached plating. Section 5 Corrosion Protection 1 General 1.2 Protection of seawater ballast tanks and void double side skin spaces NO KC entry The first paragraph is modified as follow: For ships contracted for construction on or after 8 December 2006, the date of IMO adoption of the amended SOLAS regulation II-1/3-2, by which an IMO Performance standard for protective coatings for ballast tanks and void spaces will be made mandatory, the coatings of internal spaces subject to the amended SOLAS regulation are to satisfy the requirements of the IMO performance standard. NO KC entry The following paragraph is added after the first paragraph: For ships contracted for construction on or after 1 July 2012, the IMO performance standard is to be applied as interpreted by IACS UI SC 223 and UI SC 227. In applying IACS UI SC 223, Administration is to be read to be the Classification Society. 6 / 34 Rule Change Notice 1 July 2010 edition

15 1.3 Protection of cargo hold space Side areas to be coated KC 1009 The third item of the bullet list is modified as follow (the remaining text and figure are not modified): The areas to be coated are the internal surfaces of: the inner side plating the internal surfaces of the topside tank sloping plates the internal surfaces of the hopper tank sloping plates for a distance of 300 mm below the frame end bracket for single side bulk carriers holds of single side skin construction, or below the hopper tank upper end for double side bulk carriers holds of double side skin construction Transverse bulkhead areas to be coated KC 1009 The text is modified as follow: The areas of transverse bulkheads to be coated are all the areas located above an horizontal level located at a distance of 300 mm below the frame end bracket for single side bulk carriers holds of single side skin construction, or below the hopper tank upper end for double side bulk carriers holds of double side skin construction. Section 6 Structural Arrangement Principles 1 Application KC 414 The current text is replaced by the following one: If not specified otherwise, the requirements of this section apply to the cargo hold area the hull structure except superstructures and deckhouses. For other areas outside the cargo holds area, the requirements of Ch 9 Sec 1 to Ch 9 Sec 4 are to be applied supplementary requirements are to be found in Ch. 9 Sec 1 to Ch. 9 Sec 3. Rule Change Notice 1 July 2010 edition 7 / 34

16 2. General principles 2.3 Connections with higher tensile steel Connections with higher tensile steel KC 207 KC 208 KC 398 The last sentence of the last paragraph is replaced by the following one: The same requirement is generally applicable for non continuous longitudinal stiffeners welded on the web of a primary member contributing to the hull girder longitudinal strength as hatch coamings, stringers and girders. 4 Ordinary stiffener 4.1 Profile of stiffeners Stiffener profile with a bulb section KC 1004 The first paragraph is replaced by the following one: The properties of bulb profile sections are to be determined by exact calculations. If it is not possible, a bulb section may be taken as equivalent to a built-up section. The dimensions of the equivalent built-up section are to be obtained, in mm, from the following formulae. 5. Primary supporting members 5.2 Stiffening arrangement KC 328 The third paragraph is modified as follow: The net thickness of web stiffeners and brackets, in mm, are not to be less than the minimum net thickness of the primary members on which they are fitted. the value obtained from the following formula: t = L 2 where: L 2 : Rule length L, but to be taken not greater than 300 m 8 / 34 Rule Change Notice 1 July 2010 edition

17 The last paragraph is modified as follows: KC 760 Depth of stiffener of flat bar type is in general to be more than 1/12 of stiffener length. A smaller depth of stiffener may be accepted based on calculations showing compliance with Ch 6 Sec 2 [2.3.1], Ch 6 Sec 2 [4] and Ch 6 Sec 3 [4]. 5.4 Effective breadth of primary supporting member General KC 590 The current text is replaced by the following one: The effective breadth b p of the attached plating of a primary supporting member to be considered in the actual net section modulus for the yielding check is to be taken as the mean spacing between adjacent primary supporting members is to be determined according to [4.3.1]. 6 Double bottom 6.1 General Height of double bottom KC 758 The first paragraph of the requirement is modified as follow. Unless otherwise specified, the height of double bottom is not to be less than B/20 or 2 m whichever is the lesser. Where a double bottom is required to be fitted the inner bottom shall be continued transversely in such a manner as to protect the bottom to the turn of the bilge. Such protection will be deemed satisfactory if the inner bottom is not lower at any part than a plane parallel with the keel line and which is located not less than a vertical distance h measured from the keel line, as calculated by the formula: h = B/20 However, in no case is the value of h to be less than 760 mm, and need not be taken as more than 2,000 mm. Rule Change Notice 1 July 2010 edition 9 / 34

18 KC 414 The following title is changed as follow: 7. Double side structure in cargo hold area KC 414 The following title is changed as follow: 8. Single side structure in cargo hold area 9. Deck structure 9.2 General arrangement Deck between hatches KC 630 The first paragraph is to be replaced by the following one: Inside the line of openings, a transversely framed structure is to be generally adopted for the cross deck structures., hhatch end beams and cross deck beams are to be adequately supported by girders and extended up outward to the second longitudinal from the hatch side girders towards the bulwark the deck side. Where this is impracticable, intercostal stiffeners are to be fitted between the hatch side girder and the second longitudinal. If the extension of beams outward to the second longitudinal is not achievable, structural checks of the structure are to be performed in compliance with the requirements in Ch.7 or by means deemed appropriate by the Society. 10. Bulkhead structure 10.5 Non-tight bulkheads Non-tight bulkheads not acting as pillars KC 417 The following paragraph is added before the current last one: The net thickness of bulkhead stiffener, in mm, is not to be less than the value obtained from the following formula: t = L 2 10 / 34 Rule Change Notice 1 July 2010 edition

19 where: L 2 : Rule length L, but to be taken not greater than 300 m KC 760 The last paragraph is modified as follows: The depth of bulkhead stiffener of flat bar type is in general not to be less than 1/12 of stiffener length. A smaller depth of stiffener may be accepted based on calculations showing compliance with Ch 6 Sec 2 [2.3.1], Ch 6 Sec 2 [4] and Ch 6 Sec 3 [4]. The net thickness of bulkhead stiffener is not to be less than the minimum thickness required for the considered bulkhead plate. Rule Change Notice 1 July 2010 edition 11 / 34

20 Chapter 4 Design Loads Section 5 External Pressures 4. Pressure in bow area 4.1 Bow flare area pressure KC 653 The definition of p is replaced by the following one: p S, p W : Hydrostatic pressure and maximum hydrodynamic pressures among load cases H, F, R and P, calculated in normal ballast condition at T B at considered point of the hull in normal ballast condition. Minimum ballast draught in ballast condition T B defined in Ch 1, Sec 4, [2.1.1] is to be considered as T LCi for the calculation of hydrostatic pressure and hydrodynamic pressures. Section 6 Internal Pressures and Forces 4. Testing lateral pressure 4.1 Still water pressure KC 966 In Table 2, the text concerning ballast hold and the notes at the bottom of the table are changed as follow: Table 2 Testing load height Compartment or structure to be tested Testing load height, in m 12 / 34 Rule Change Notice 1 July 2010 edition

21 Compartment or structure to be tested Testing load height, in m where: z ml : Z co-ordinate, in m, of the margin line bulkhead deck at side. z h : Z co-ordinate, in m, of the top of hatch coaming. z F : As defined in [3.2.1]. z fd : Z co-ordinate, in m, of the freeboard deck. : Setting pressure, in bar, of safety valves. p PV Rule Change Notice 1 July 2010 edition 13 / 34

22 Chapter 5 Hull Girder Strength Section 1 Yielding Check 2. Hull girder stresses 2.2 Shear stresses Simplified calculation of shear stresses induced by vertical shear forces KC 1009 The text is modified as follow in the first column of the table 1(the remaining text and figures are unchanged): Table 1: Shear stresses induced by vertical shear forces Ship typology Location t, in mm δ Single side ship skin construction Double side ship skin construction where: t S, t IS Sides t S 0,5 Sides t S 0.5( 1 φ) Inner sides t IS 0.5φ : Minimum net thicknesses, in mm, of side and inner side, respectively t SM, t ISM : Mean net thicknesses, in mm, over all the strakes of side and inner side, respectively. They φ are calculated as Σ( i t i ) / Σ i, where i and t i are the length, in m, and the net thickness, in mm, of the i th strake of side and inner side. t : Coefficient taken equal to: φ = t ISM SM 14 / 34 Rule Change Notice 1 July 2010 edition

23 Chapter 6 Hull Scantlings Section 1 Plating 3. Strength check of plating subjected to lateral pressure 3.2 Plating thickness Net thickness of the corrugations of transverse vertically corrugated watertight bulkheads separating cargo holds for flooded conditions KC 565 The definition of p is replaced by the following one: p : pressure p F or resultant pressure p, in kn/m 2, as defined in Ch 4, Sec 6 [3.3.6] and [3.3.7], respectively Section 2 Ordinary stiffeners 3. Yielding check 3.6 Scantlings of transverse vertically corrugated watertight bulkheads separating cargo holds for flooded conditions Bending capacity and shear capacity of the corrugations of transverse vertically corrugated watertight bulkheads separating cargo holds KC 565 The definition of p is replaced by the following one: F p G : force F F or resultant force F, in kn, to be calculated according to Ch 4, Sec 6, [3.3.6] and [3.3.7], respectively : pressure p F or resultant pressure p, in kn/m², to be calculated in way of the middle of the shedders or gusset plates, as applicable, according to Ch 4, Sec 6, [3.3.6] and [3.3.7], respectively Rule Change Notice 1 July 2010 edition 15 / 34

24 4. Web stiffeners of primary supporting members 4.1 Net scantlings Connection ends of web stiffeners KC 764 The second formula is modified as follow (new formula in red box): Where the web stiffeners of primary supporting members are welded to ordinary stiffener face plates, the stress at ends of web stiffeners of primary supporting members in water ballast tanks, in N/mm 2, is to comply with the following formula when no bracket is fitted: σ 175 where: σ = 1.1K con Klongi K stiff σ cosθ σ = Kcon Klongi K stiff σ cosθ Section 3 Buckling and ultimate strength of ordinary stiffeners and stiffened panels 4. Buckling criteria of partial and total panels 4.2 Ultimate strength in lateral buckling mode Evaluation of the bending stress σ b KC 768 The requirement is modified as follow (all the text is included here for the sake of the editor but only the changes are to be considered): The bending stress σ b, in N/mm 2, in the stiffeners is equal to: σ b M 0 + M = W 10 st 1 3 with: M 0 : Bending moment, in N.mm, due to the deformation w of stiffener, taken equal to: M 0 = F Ki pz w c p f z With ( c p ) > 0 f z 16 / 34 Rule Change Notice 1 July 2010 edition

25 M 1 : Bending moment, in N.mm, due to the lateral load p, taken equal to: 2 M 1 = pba for longitudinal stiffeners M 1 ( n b) 2 pa = for transverse stiffeners, with n equal to 1 for ordinary transverse 3 c 10 8 S stiffeners. W st : Net section modulus of stiffener (longitudinal or transverse), in cm 3, including effective width of plating according to [5], taken equal to: if a lateral pressure is applied on the stiffener: W st is the net section modulus calculated at flange if the lateral pressure is applied on the same side as the stiffener. W st is the net section modulus calculated at attached plate if the lateral pressure is applied on the side opposite to the stiffener. Note: For stiffeners sniped at both ends, W st is the net section modulus calculated at attached plate. However, if M 1 is larger than M 0 and the lateral pressure is applied on the same side as the stiffener, Wst is the net section modulus calculated at flange. if no lateral pressure is applied on the stiffener: W st is the minimum net section modulus among those calculated at flange and attached plate Note: For stiffeners sniped at both ends, W st is the net section modulus calculated at attached plate. c S : Factor accounting for the boundary conditions of the transverse stiffener c S = 1.0 for simply supported stiffeners c S = 2.0 for partially constraint stiffeners p : Lateral load in kn/m 2, as defined in Ch 4, Sec5 and Ch 4, Sec 6 calculated at the load point as defined in Ch 6, Sec 2, [1.4] F Ki : Ideal buckling force, in N, of the stiffener, taken equal to: F 2 π 4 = 10 for longitudinal stiffeners a Kix EI 2 x F Kiy 2 π 4 = EI 10 for transverse stiffeners ( nb) 2 y I x, I y : Net moments of inertia, in cm 4, of the longitudinal or transverse stiffener including effective width of attached plating according to [5]. I x and I y are to comply with the following criteria: Rule Change Notice 1 July 2010 edition 17 / 34

26 I x I y bt at p z : Nominal lateral load, in N/mm 2, of the stiffener due to σ x, σ y x, y and τ 2 t a π b p = σ + 2 σ + τ 2 zx xl c y y 1 b a for longitudinal stiffeners 2 t a π a Ay p + zy = 2cxσ xl + σ y 1 + τ1 2 for transverse stiffeners a nb ata σ xl A x = σ x 1+ b t a t a : Net thickness offered of attached plate, in mm c x, c y : Factor taking into account the stresses vertical to the stiffener's axis and distributed variable along the stiffener's length taken equal to: 0.5 (1 + ψ ) for 0 ψ ψ for ψ < 0 A x, A y : Net sectional area, in mm 2, of the longitudinal or transverse stiffener respectively without attached plating τ = τ t ReH E m a m b 0 m 1, m 2 : for longitudinal stiffeners: Coefficients taken equal to: a 2,0 b a < 2,0 b : : m = m = m m 2 2 = 0.49 = 0.37 for transverse stiffeners: a 0,5 n b a < 0,5 n b : : m = m = m m = 2 n 1.47 = 2 n w = w 0 + w 1 generally w = w 0 w 1 for stiffeners sniped at both ends, on which the same side lateral pressure as the stiffener is applied. w 0 : Assumed imperfection, in mm, taken equal to: 18 / 34 Rule Change Notice 1 July 2010 edition

27 a b w 0 = min(,,10) for longitudinal stiffeners w 0 a n b = min(,,10) for transverse stiffeners For stiffeners sniped at both ends w 0 must not be taken less than the distance from the midpoint of attached plating to the neutral axis of the stiffener calculated with the effective width of its attached plating. w 1 : Deformation of stiffener, in mm, at midpoint of stiffener span due to lateral load p. In case of uniformly distributed load the following values for w 1 may be used: 4 pba w1 = for longitudinal stiffeners EI x 4 5ap( nb) w1 = EI for transverse stiffeners 2 y c S c f : Elastic support provided by the stiffener, in N/mm 2, taken equal to: for longitudinal stiffeners: π c f = FKix (1 + c 2 a 2 px ) c px = I t b 1+ c xa x 1 c xa : Coefficient taken equal to : 2 a 2b c xa = + 2 for a 2b b a 2 2 a 1 2 c xa = + for a < 2b b for transverse. stiffeners: π c = c F 1+ f S Kiy 2 ( n b) 2 ( c ) py c py 1 = I t a 1+ c ya y 1 c ya : Coefficient taken equal to: Rule Change Notice 1 July 2010 edition 19 / 34

28 2 nb 2a c ya = + 2 for nb 2a a nb 2 2 nb c ya = 1 + for nb < 2a 2a Equivalent criteria for longitudinal and transverse ordinary stiffeners not subjected to lateral pressure KC 800 The requirement is modified as follow (all the text is included here for the sake of the editor but only the changes are to be considered): Longitudinal and transverse ordinary stiffeners not subjected to lateral pressure, except for sniped stiffeners, are considered as complying with the requirement of [4.2.1] if their net moments of inertia I x and I y, in cm 4, are not less than the value obtained by the following formula: For longitudinal stiffener : I 2 2 p zxa w 0hw a = π 10 ReH σ π E x S x 2 For transverse stiffener : I 2 p zy ( nb) 2 w 0hw ( nb) = π 10 ReH σ π E y S y 2 Section 4 Primary supporting members 1 General KC 654 The following article is added: 1.6 Flooding check of primary supporting members General Flooding check of primary supporting members is to be carried out according to the requirements in [5]. 20 / 34 Rule Change Notice 1 July 2010 edition

29 The following article is added: KC Flooding check of primary supporting members 5.1 Net section modulus and net shear sectional area under flooded conditions The net section modulus w, in cm 3, the net shear sectional area to be not less than the values obtained from the following formulae: 2 pf s w = 10 16αλS RY 3 A sh, in cm 2 subjected to flooding are A sh = 5p ατ sin φ a F s Where : α: Coefficient taken equal to: α = 0.95 α = 1.15 for the primary supporting member of collision bulkhead, for the primary supporting member of other watertight boundaries of compartments. λ S : Coefficient defined in Ch 6, Sec 4 Table 11, determined by considering σ X in flooded condition. p F : Pressure, in kn/m 2, in flooded conditions, defined in Ch 4, Sec 6, [3.2.1]. Rule Change Notice 1 July 2010 edition 21 / 34

30 Chapter 7 Direct Strength Analysis Section 3 Detailed Stress Assessment 2 Analysis model 2.1 Areas to be refined KC 1009 The text is modified as follow in the second column of the table 2 (the remaining text and figures are unchanged): Table 1: Typical details to be refined Structural member Area of interest Additional specifications Description Most stressed transverse primary supporting member for double skin side bulk carriers skin constructions Refining of the most stressed transverse primary supporting members located in: double bottom hopper tank double skin side topside tank Primary supporting member Most stressed transverse primary supporting member for single skin side bulk carriers skin constructions Refining of the most stressed transverse primary supporting members located in: double bottom hopper tank topside tank side shell frame with end brackets and connections to hopper tank and topside tank 22 / 34 Rule Change Notice 1 July 2010 edition

31 Chapter 8 Fatigue Check of Structural Details Section 1 General Consideration 1. General 1.3 Subject members KC 854 The current text is replaced by the following one before Table 1: Fatigue strength is to be assessed, in cargo hold area, for members described in Tab 1, at the considered locations. for all the connected members at the considered locations described in Tab 1. Section 4 Stress Assessment of Stiffeners 2. Hot spot stress range 2.3 Stress range according to the simplified procedure Stress due to dry bulk cargo pressure KC 571 The definition of p cw,ij(k) is replaced by the following one: p CW, i j(k) : Inertial pressure, in kn/m 2, due to dry bulk cargo specified in Ch 4, Sec 6, [1.3] for a cargo density ρ C specified in Ch.4 Annex 3,, and with f p = 0.5, in load case i1 and i2 for loading condition (k) Rule Change Notice 1 July 2010 edition 23 / 34

32 Appendix 1 Cross Sectional Properties for Torsion 2 Example calculation for a single side hull cross section 2.5 Notes KC 1009 The first sentence of the requirement is modified as follow (the remaining text of the requirement is unchanged): For single side bulk carriers holds of single side skin construction,, the hull cross section normally can be simplified in a section with four boxes (cell 1 cargo hold, cell 2 and 3 wing tanks and cell 4 hopper tanks and double bottom as shown in the calculation example) whereas the cross section of a double side bulk carriers holds of double side skin construction, can be simplified to a cross section with two closed cells only (cell 1 cargo hold, cell 2 double hull). 24 / 34 Rule Change Notice 1 July 2010 edition

33 Chapter 9 Other Structures Section 1 Fore Part Symbols KC 666 The symbols values and definitions are modified as follow: m : Coefficient taken equal to: m = 10 for vertical stiffeners, vertical primary supporting members m = 12 for other stiffeners, other primary supporting members s : l : Spacing, in m, of ordinary stiffeners or primary supporting members, measured at mid-span along the chord Span, in m, of ordinary stiffeners or primary supporting members, measured along the chord between the supporting members, see Ch 3, Sec 6, [4.2] or [5.3] respectively. 1. General 1.1 Application KC 524 The following text is added: Fore part structures which form the boundary of spaces not intended to carry liquids, and which do not belong to the outer shell, are to be subjected to lateral pressure in flooding conditions. Their scantlings are to be determined according to the relevant criteria in Ch.6. Rule Change Notice 1 July 2010 edition 25 / 34

34 2. Arrangement 2.3 Floors and bottom girders Solid floors KC 759 The item is amended as follows: In case of transverse framing, solid floors are to be fitted at every frame. In case of the longitudinal framing, the spacing of solid floors is not to be greater than 3.5m or four transverse frame spaces, whichever is the smaller. Larger spacing of solid floors may be accepted, provided that the structure is verified by means of FEA deemed appropriate by the Society Bottom girder KC 759 The item is amended as follows: In case of transverse framing, the spacing of bottom girders is not to exceed 2.5m. In case of longitudinal framing, the spacing of bottom girders is not to exceed 3.5m. Larger spacing of bottom girders may be accepted, provided that the structure is verified by means of FEA deemed appropriate by the Society. 4. Scantlings 4.2 Plating KC 494 The last row is added to Table 1 as follow: Table 1 Net minimum thickness of plating Minimum net thickness, in mm Bottom L Side 0.85L 1/2 Inner bottom L Strength deck L Platform and wash bulkhead 6.5 Transverse and longitudinal 0.6L 1/2 watertight bulkheads 26 / 34 Rule Change Notice 1 July 2010 edition

35 4.4 Primary supporting members Deck primary supporting members KC 666 The current text is replaced by the following one: Scantlings of deck primary supporting members are to be in accordance with Ch 6, Sec 4, considering the loads in [3.2] and [3.3]. The net scantlings of deck primary supporting members are to be not less than those obtained from the formulae in Table 5. The design pressures in the formulae are taken from intact conditions and testing conditions respectively as stated in [3.2]. For a complex deck structure, a calculation deemed appropriate by the Society may be carried out in lieu of the formulae. Table 5 Net scantlings of deck primary supporting members Condition Primary supporting members subjected to lateral pressure in intact conditions Primary supporting members subjected to lateral pressure in testing conditions where: φ Net section modulus w, in Net sectional shear area A sh, cm 3 in cm 2 w = 2 ( p + p ) s 3 S W 0.9mRY 2 pt s w = mRY 10 3 A sh A sh 5 = ( p + p ) S W s τ sinφ a 5 pt s = 1.05τ sin φ : Angle, in deg, between the primary supporting member s web and the shell plate, measured at the middle of the primary supporting member s span; the correction is to be applied when φ is less than 75. a The subsequent existing Table 5 to Table 7 shall be renumbered accordingly. KC 567 The title is replaced modified as follow: 5. Strengthening of flat bottom forward area 5.1 Application KC 567 The current text is replaced by the following one: The flat bottom forward area to be reinforced is the flat part of the ship's bottom extending forward of 0.2V L from the fore perpendicular end, up to a height of 0.05T B or 0.3 m above base line, whichever is the smaller. Rule Change Notice 1 July 2010 edition 27 / 34

36 5.2 Bottom plating KC 567 The first paragraph is replaced by the following one: The net thickness, in mm, of the flat bottom forward area, is not to be less than: 5.3 Ordinary stiffeners KC 567 The first paragraph is replaced by the following one: The net section modulus, in cm 3, of transverse or longitudinal ordinary stiffeners of the flat bottom forward area is not to be less than: KC 567 The first paragraph is replaced by the following one: The net shear area, in cm 2, of transverse or longitudinal ordinary stiffeners of the flat bottom forward area is not to be less than: Section 2 AFT PART Symbols KC 666 The symbols values and definitions are modified as follow: m : Coefficient taken equal to: m = 10 for vertical stiffeners, vertical primary supporting members m = 12 for other stiffeners, other primary supporting members s : Spacing, in m, of ordinary stiffeners or primary supporting members, measured at mid-span along the chord l : Span, in m, of ordinary stiffeners or primary supporting members, measured along the chord between the supporting members, see Ch 3, Sec 6, [4.2] or [5.3] respectively. 28 / 34 Rule Change Notice 1 July 2010 edition

37 4 Scantlings 4.1 Plating KC 494 The last row is added to Table 1 as follow: Table 1 Net minimum thickness of plating Minimum net thickness, in mm Bottom L Side 0.85L 1/2 Inner bottom L Strength deck L Platform and wash bulkhead 6.5 Transverse and longitudinal watertight bulkheads 4.3 Primary supporting members 0.6L 1/ Deck primary supporting members KC 666 The current text is replaced by the following one: Scantlings of deck primary supporting members are to be in accordance with Ch 6, Sec 4, considering the loads in [2.2]. The net scantlings of deck primary supporting members are to be not less than those obtained from the formulae in Table 5. The design pressures in the formulae are taken from intact conditions and testing conditions respectively as stated in [2.2]. For a complex deck structure, a direct strength calculation may be carried out in lieu of the formulae. Rule Change Notice 1 July 2010 edition 29 / 34

38 Table 5 Net scantlings of deck primary supporting members Condition Primary supporting members subjected to lateral pressure in intact conditions Primary supporting members subjected to lateral pressure in testing conditions where: φ Net section modulus w, in Net sectional shear area A sh, cm 3 in cm 2 w = 2 ( p + p ) s 3 S W 0.9mRY 2 pt s w = mRY 10 3 A sh A sh 5 = ( p + p ) S W s τ sinφ a 5 pt s = 1.05τ sin φ : Angle, in deg, between the primary supporting member s web and the shell plate, measured at the middle of the primary supporting member s span; the correction is to be applied when φ is less than 75. a The subsequent existing Table 5 and Table 6 shall be renumbered accordingly. Section 3 Machinery Space 2. Double bottom 2.1 Arrangement Side bottom girders in way of machinery seatings KC 836 The current text for the fourth paragraph is replaced by the following one: Forward of the machinery space forward bulkhead, the bottom girders are to be generally tapered for at least three frame spaces and are to be effectively connected to the hull structure. 30 / 34 Rule Change Notice 1 July 2010 edition

39 Section 5 Hatch Covers 4. Load Model 4.2 Load Point KC 304 The title and the requirement are changed as follow: Wave lateral pressure for hatch covers on exposed decks Sea pressures The wave lateral pressure to be considered as acting on each hatch cover is to be calculated at a point located: longitudinally, at the hatch cover mid-length. longitudinally, at the hatch cover mid-length transversely, on the longitudinal plane of symmetry of the ship vertically, at the top of the hatch cover. KC 304 The title is changed as follow: Lateral pressures other than the wave pressure Other pressures The lateral pressure is to be calculated: in way of the geometrical centre of gravity of the plate panel, for plating at mid-span, for ordinary stiffeners and primary supporting members. KC 304 The following text is added to the requirement: Internal dynamic lateral pressure to be considered as acting on the bottom of a hatch cover is to be calculated at a point located: longitudinally, at the hatch cover mid-length transversely, at hatchway side Vertically, at the top of the hatch coaming for internal ballast water pressures Rule Change Notice 1 July 2010 edition 31 / 34

40 Chapter 10 Hull Outfitting Section 1 Rudder and Manoeuvring Arrangement 5. Rudder body, rudder bearings 5.1 Strength of rudder body KC 568 In the article, the current values are replaced by the following ones: bending stress, N/mm 2, due to M R : σ b = equivalent stress, in N/mm2, due to bending and shear and equivalent stress due to bending and torsion: 2 σ v1 = σ b + 3τ = / 34 Rule Change Notice 1 July 2010 edition

41 Chapter 11 Construction and Testing Section 2 Welding 2. Types of welded connections 2.2 Butt welding Welding of plates with different thicknesses KC 938 The text of this item is replaced by the following one: In the case of welding of plates with a difference in as-built thickness equal to or greater than 4 mm, the thicker plate is normally to be tapered. The taper has to have a length of not less than 3 times the difference in as-built thickness. 2.4 Full penetration welds Application KC 848 The last item in the list is replaced by the following one: abutting plate panels with as-built thickness less than or equal to 12mm, forming boundaries to the sea below the summer load water line. For as-built thickness greater than 12mm, deep penetration weld with a maximum root face length f = T/3 is acceptable (see Fig.2). Rule Change Notice 1 July 2010 edition 33 / 34

42 Section 3 Testing of Compartments 3. Testing requirements 3.1 General KC 966 In Table 1, the line No 4 and note 2 are changed as follow: Item number Structural to be tested Type of testing Structural test pressure Remarks 4 Ballast holds Structural testing (1) The greater of the following: head of water up to the top of overflow, or 0.9 head of water above top of hatch top of hatch coaming 34 / 34 Rule Change Notice 1 July 2010 edition

43 C OMMON STRUCTURAL RULES FOR B ULK CARRIERS J ULY 2010 Rule Changes Notice Technical Background Number 1 to the 2010 Edition Notes: (1) These Rule Changes enter into force on July (2) This Rule Change Notice Technical Background should be read in conjunction with the July 2010 consolidated edition of Bulk Carriers CSR. Copyright in these Common Structural Rules for Bulk Carriers is owned by: American Bureau of Shipping Bureau Veritas China Classification Society Det Norske Veritas Germanischer Lloyd Korean Register of Shipping Lloyd's Register Nippon Kaiji Kyokai Registro Italiano Navale Russian Maritime Register of Shipping Copyright 2010 The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as the IACS Members. The IACS Members, individually and collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant IACS Member entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

44

45 Table of contents 1. Introduction Scope of application Content of the document Cross references Change descriptions PSPC application KC 207, 208 & 398 Connection with high tensile steel KC 304 Load Calculation point for Hatch Cover KC 328 Net thickness of web stiffeners and brackets of primary supporting members KC 414 Application of structural arrangement principles KC 417 Net thickness of non-tight bulkhead stiffeners not acting as pillars KC 494 Transverse and longitudinal watertight bulkheads minimum net thickness KC 524 Fore Part structures in flooding condition KC 565 Scantlings of transverse vertically corrugated watertight bulkhead separating cargo holds for flooded conditions KC 567 Bilge definition KC 568 Strength of Rudder Body KC 571 Cargo mass in fatigue stress assessment KC 590 Effective breadth of attached plating for primary supporting members KC 630 Deck between hatches KC 653 Bow flare area pressure KC 654 Primary supporting members under flooded condition KC 666 Deck Primary Supporting Members KC 758 Height of double bottom KC 759 Spacing of solid floors KC 760 Depth of web stiffener KC 764 Connection ends of web stiffeners KC 768 & KC 800 Ultimate Strength in Lateral Buckling Mode KC 773 Corrosion addition of longitudinal stiffeners KC 793 Cofferdam arrangement KC 798 SOLAS Subdivision arrangement KC 836 Side bottom girders in way of machinery seatings KC 848 Harmonisation of welding of abutting plates below the waterline KC 854 Members subjected to fatigue strength assessment Technical Background of Rule Change Notice 1 July 2010 edition i / iv

46 2.29 KC 903 Collision Bulkhead KC 938 Harmonisation of tapering between abutting plates KC 966 Load Testing Height KC 1004 Bulb stiffener s properties KC 1009 Single side and double side definitions KC 1082 Minimum bow height Appendix 1. KC666 related documents App.1.1. Introduction App.1.2. Fore peak area App.1.3. Aft peak area App.1.4. Conclusion Appendix 2. KC 328 related documents Appendix 3. KC 798 Related documents App.3.1. SOLAS Chapter II-1 Part B Regulation App.3.2. SOLAS Chapter II-1 Part B Regulation App.3.3. SOLAS Chapter II-1 Part B-2 Regulation Appendix 4. KC 966 related document App.4.1. IACS Guideline for Procedures of Testing Tanks and Tight Boundaries Appendix 5. KC 1009 related documents App.5.1. SOLAS Chapter IX Regulation App.5.2. SOLAS Chapter XII Regulation App.5.3. Resolution MSC.79(70) App.5.4. SOLAS/CONF.4 Resolution App.5.5. UR Z10.2- Rev. 27 (March 2009) App.5.6. UR Z10.5- Rev. 9 (March 2009) Appendix 6. KC 1082 related documents App.6.1. SOLAS Chapter IX Regulation List of Tables Table 1 KC per rule references... 1 Table 2 Changes applied per KC entries... 3 Table 3 KC 328 offered net scantlings of the web stiffeners which satisfy the requirement in Chaper3, Section 6, [5.2.1], Chaper6, Section 2, [4.1.1] and [4.1.2]... 9 ii / iv Technical Background of Rule Change Notice 1 July 2010 edition

47 Table 4 Table 5 Table 6 KC 328 offered net scantlings of the web stiffeners which satisfy the requirement of the proposed Rule Change KC 417 Investigation data about the net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars KC 417 Comparison for the required net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars in CSR and the proposed Rule Change Table 7 KC 666 Comparison of current scantlings requirements for PSM Table 8 KC 1009 Double-side skin width equivalent to a single-side skin as per SOLAS XII Table 9 KC 666 Main characteristics of typical bulk carriers Table 10 KC 666 Allowable stresses Table 11 KC 666 Fore peak arrangements for typical bulk carriers Table 12 KC 666 Fore peak, net section modulus with the current rules Table 13 KC 666 Fore peak, net section modulus with the proposed change Table 14 KC 666 Fore peak, net shear area with the current rules Table 15 KC 666 Fore peak, net shear area with the proposed change Table 16 KC 666 Aft peak, net section modulus with the current rules Table 17 KC 666 Aft peak, net section modulus with the proposed change Table 18 KC 666 Aft peak, net shear area with the current rules Table 19 KC 666 Aft peak, net shear area with the proposed change Table 20 Table 21 Table 22 Table 23 KC net thickness of web stiffeners and brackets on double bottom floor KC 238 net thickness of web stiffeners and brackets on double bottom girder KC 328 net thickness of web stiffeners and brackets on PSM in bilge hopper tanks KC 328 net thickness of web stiffeners and brackets on PSM in topside tanks List of Figures Figure 1 Figure 2 KC 417 Comparison for the net offered thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars and net min required thickness in CSR-BC and the proposed Rule Change KC 417 Comparison for the required net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars in CSR and the proposed Rule Change Figure 3 KC 567 ambiguous bilge area in the fore part Figure 4 KC 768 & 800 Moment and forces on a snipped stiffener in lateral buckling Figure 5 KC 666 Possible fore peak arrangements Figure 6 KC 666 used aft peak arrangements Figure 7 KC Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on double bottom floor Technical Background of Rule Change Notice 1 July 2010 edition iii / iv

48 Figure 8 Figure 9- Figure 10 KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on double bottom girder KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on PSM in bilge hopper tanks KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on PSM in topside tanks iv / iv Technical Background of Rule Change Notice 1 July 2010 edition

49 1. I NTRODUCTION 1.1 Scope of application This Technical Background is intended for the understanding of the following Rule Change Notice: Rule Change Notice number : Number 1 to the 2010 Edition Entry into force of the Rule Change Notice : July 2012 Concerned rules : Common Structural Rules for Bulk Carriers Edition date of the rules : July Content of the document As the changes are initiated by questions in the IACS Knowledge Centre (KC), this document presents all the KC entries that lead to rules changes and give for each the following elements: The description of the change, The modifications made accordingly, The scantling impacts. It is to be pointed up that a KC entry may lead to changes in more than one item in the text and that any item in the text may be affected by more than one KC entry. 1.3 Cross references Table 1 gives the list of KC leading to a change in each modified item in the rules. Table 2 gives the list of rule changes induced by each KC entry. Table 1 KC per rule references Chapter Section Sub.1 Sub.2 Sub.3 Table Figure KC ref. click to go Technical Background of Rule Change Notice 1 July 2010 edition 1 / 63

50 Chapter Section Sub.1 Sub.2 Sub.3 Table Figure KC ref. click to go KC PSPC application / 63 Technical Background of Rule Change Notice 1 July 2010 edition

51 Chapter Section Sub.1 Sub.2 Sub.3 Table Figure KC ref. click to go A Symbols Symbols Table 2 Changes applied per KC entries KC ref. click to go Chapter Section Sub.1 Sub.2 Sub.3 Table Figure PSPC Technical Background of Rule Change Notice 1 July 2010 edition 3 / 63

52 KC ref. click to go Chapter Section Sub.1 Sub.2 Sub.3 Table Figure Symbols Symbols / 63 Technical Background of Rule Change Notice 1 July 2010 edition

53 KC ref. click to go Chapter Section Sub.1 Sub.2 Sub.3 Table Figure A KC Technical Background of Rule Change Notice 1 July 2010 edition 5 / 63

54 2. C HANGE DESCRIPTIONS 2.1 PSPC application Rule Change description This change is not based on a KC question. The proposed amendment is to indicate the adoption date of the Performance standard for protective coatings for ballast tanks and void spaces by IMO, and to reference the IACS Unified Interpretation UI SC223 and SC227 for transparent application by IACS members Applied change Chapter 3 Section 5 [1.2.2] Details are added about the application of PCPC to CSR BC Impact on scantling There is no impact on scantlings. 2.2 KC 207, 208 & 398 Connection with high tensile steel Rule Change description The requirement in Chapter 3 Section 6 [2.3.1] is of general scope. As the stress level due to hull girder bending in longitudinal member not contributing to hull girder longitudinal strength, is verified in order to satisfy the requirement in Ch 5, Sec 1, [3.1.1], application of the requirements in Ch 3, Sec 6, [2.3.1] might be mitigated. In addition, designs where non continuous stiffeners made of mild steel are welded on girders made of high tensile steels are already accepted by classification societies. The requirement is made less mandatory for non-continuous longitudinal stiffeners by adding the word generally Applied change Chapter 3 Section 6 [2.3.1] The word generally is added in the last sentence of the item between The same requirement and is applicable Impact on scantling This requirement is about the steel grade to be used for non-continuous longitudinal stiffeners when they are welded on the web of a primary supporting member contributing to the hull girder longitudinal strength. As the scantling of these stiffeners is assessed in the hull girder strength, there is no valuable modification of the scantling or the steel weight. 6 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

55 2.3 KC 304 Load Calculation point for Hatch Cover Rule Change description Currently, the load model used for hatch covers defines a single load calculation point in Chapter 9 Section 5 [4.2.1] for sea pressures or internal ballast water pressures. In addition the wording Wave lateral pressure may lead to some confusion, as it is used for dynamic pressure (induced by the sea waves). The main intention of this rule change is to differentiate the actions of external sea loads acting on the top of the hatch cover and which effects are described initially by ILLC, internal ballast water acting on the bottom of hatch covers. The current requirement in Chapter 9 Section 5 [4.2.1] defines the load calculation point for external sea pressures only. As the ILLC approach used in these rules is based only on the longitudinal position of the hatch cover, the requirement is modified to refer only to the longitudinal position. For the other pressures acting on a hatch cover, the current requirement in Chapter 9 Section 5 [4.2.2] defines the load calculation point for other lateral pressures for plating, ordinary stiffeners or primary supporting members. The particular case of internal water ballast pressure is added with the definition of the load calculation point to be considered on the inner face of the hatch cover. The calculated pressure is then to be used over the different structural elements of the hatch cover at the positions defined in the requirement. This changes intents to clarify all these points in the rules by: changing the title of Chapter 9 Section 5 [4.2.1] to Sea pressures changing the title of Chapter 9 Section 5 [4.2.2] to Other pressures adding the definition of the load calculation point on the bottom of the hatch coaming as follow: longitudinally, at the hatch cover mid-length, transversely, at hatchway side, vertically, at the top of the hatch coaming Applied change Chapter 9 Section 5 [4.2.1] The title is changed to Sea pressures in order to clearly state this is about sea pressures only. The requirement is simplified to refer only to the longitudinal position, which is used in the ILLC formula Chapter 9 Section 5 [4.2.2] The title is changed to clearly state this is about other pressures. The particular case of the internal water ballast pressure acting on the bottom of the hatch cover is considered by adding the definition of the coordinates of the load calculation point to the existing requirement Impact on scantling The proposed change has consequences only onto the values of the pressure to be considered acting on the bottom of the hatch cover. Technical Background of Rule Change Notice 1 July 2010 edition 7 / 63

56 2.4 KC 328 Net thickness of web stiffeners and brackets of primary supporting members Rule Change description The requirement in the third paragraph of Chapter 3 Section 6 [5.2.1] stating that the net thickness of web stiffeners and brackets is not to be less than the minimum net thickness of the primary supporting member on which they are fitted, is quite severe, especially for the stiffener with Bulb, Angle or T shape section. According to the CSR BC Technical Background, this regulation was established referring to the rules of various classification Societies. In order to investigate the net thickness of web stiffeners and brackets, corresponding data is gathered, which includes 4 types of non-csr Bulk Carriers, Handysize, Handymax, Panamax and Capsize, 16 ships totally, all of them are well in service Description of study According to the investigation about the net thickness of web stiffeners and brackets on representative PSMs such as: double bottom floor, double bottom girder, PSM in bilge hopper tank and in topside tank, it is found that the net offered thickness of web stiffeners and brackets for some bulk carriers are thinner than the minimum required net thickness of the PSM on which they are fitted. On the basis of the requirement of ordinary stiffener in Chapter 6, Section 2, [2.2.1]: t = L 2, a study about the proposed rule change is carried out for the requirement in Chapter 3 Section 6 [5.2.1]. In addition, it is to be noted that the scantlings of web stiffener on PSM are to satisfy the requirements in Chapter 6, Section 2, [4.1.1] and/or [4.1.2] also. The investigation data are summarized in Appendix 2, where the net offered thickness is equal to that the gross thickness diminished of the corrosion addition given in Chapter 3, Section 3, Table Conclusion of study The conclusion is as follow. 1. Double bottom floor The net offered thickness of web stiffener in three types, Panamax-1, Capesize-1 and Capesize-3, is less than the requirement in Chapter 3 Section 6 [5.2.1], but greater than that in the proposed Rule Change. 2. Double bottom Girder The net offered thickness of web stiffener in four types, Panamax-2, Capesize-1, Capesize-2 and Capesize-3, is less than the requirement in Chapter 3 Section 6 [5.2.1], but greater than that in the proposed Rule Change. 3. PSM in bilge hopper tanks The net offered thickness of web stiffener/bracket in six types, Handysize-1, Handysize-2, Panamax- 1, Panamax-2, Capesize-1 and Capesize-3, is less than the requirement in Chapter 3 Section 6 [5.2.1], but greater than that in the proposed Rule Change. 4. PSM in topside tanks The net offered thickness of web stiffener/bracket in seven types, Handysize-1, Handysize-2, Handymax-1, Panamax-1, Panamax-2, Capesize-1 and Capesize-3, is less than the requirement in Chapter 3 Section 6 [5.2.1], but greater than that in the proposed Rule Change except only the web stiffener in Panamax-1. 8 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

57 Based on the above investigation, it is reasonable and realistic that the requirement in the third paragraph of Chapter 3 Section 6 [5.2.1] is modified as that the net thickness of web stiffeners and brackets are not to be less than ( L 2 ), in mm. This requirement is similar to those of Chapter 6, Section 2, [2.2.1] and is added in the article for the convenience of the reader with all the needed definitions Applied change Chapter 3 Section 6 [5.2.1] The formula given in Chapter 6, Section 2, [2.2.1], third paragraph, replaces the current requirement. The definition of L 2 is also given Impact on scantling Because a web stiffener is to satisfy the requirements in Chaper3, Section 6, [5.2.1], Chaper6, Section 2, [4.1.1] and [4.1.2], the impact on scantling can be ignored for flat bar (FB), but the requirements are less than those before the proposed rule change for the stiffener with Bulb, Angle or T shape section Example definition 1. Basic data Rule length: L = m Corrosion addition: t C = 3.0 mm (The web stiffener is in a ballast tank.) web net thickness of PSM: t = 10.0 mm 2. Web stiffener k1 = 0.225, p = N/m 2 s = 0.84 m, l = 2.73 m (The symbols are the same as Chaper6, Section2, [4.1.1].) s = m, S s = 0.84 m (The symbols are the same as Chaper6, Section 2, [4.1.2].) Comparison of current an proposed requirements 1. Requirements in Chaper3, Section 6, [5.2.1] Web net thickness of the web stiffener: t W =10.0 mm (Chaper3, Section 6, [5.2.1]) 2. Requirements of the proposed Rule Change Web net thickness of the web stiffener: t W =7.0 mm 3. Requirements in Chaper6, Section 2, [4.1.1] and [4.1.2] The net sectional area of the web stiffener: A=18.50 cm 2 (Chaper6, Section 2, [4.1.1]) The net s section modulus of the web stiffener: W=56.77 cm3 (Chaper6, Section 2, [4.1.2]) 4. Offered scantling of the web stiffener In order to satisfy the requirement in Chaper3, Section 6, [5.2.1], the web net thickness of the web stiffener is to be 10.0 mm. In addition, the requirements in Chaper6, Section 2, [4.1.1] and [4.1.2] have to be considered. The results are listed in Table 3. Table 3 KC 328 offered net scantlings of the web stiffeners which satisfy the requirement in Chaper3, Section 6, [5.2.1], Chaper6, Section 2, [4.1.1] and [4.1.2] Dimension mm mm Type Ch3/Sec6/[5.2.1] tw (mm) Ch6/Sec2/[4.1.1] A (cm 2 ) Ch6/Sec2/[4.1.2] W (cm 3 ) Technical Background of Rule Change Notice 1 July 2010 edition 9 / 63

58 FB HP L Application of the rule change According to the proposed rule change, the required net thickness is applied to web stiffeners, 7.0 mm, the results are listed in Table 4. Table 4 KC 328 offered net scantlings of the web stiffeners which satisfy the requirement of the proposed Rule Change Dimension Ch3/Sec6/[5.2.1] Ch6/Sec2/[4.1.1] Ch6/Sec2/[4.1.2] Type mm mm tw (mm) A (cm 2 ) W (cm 3 ) FB HP L Conclusion For flat bar, although the required web net thickness is less in the proposed rule change, the values of A and W in Table 2 are less than the values in point 3 of (Requirements in Chapter 6, Section 2, [4.1.1] and [4.1.2]). Because the requirements in Chaper6, Section 2, [4.1.1] and [4.1.2] are to be satisfied, the impact on the dimension of the web stiffener can be ignored. For the stiffener with Bulb, Angle or T shape section, the dimensions of web stiffener given by this rule change are lower than those given in the 2010 edition. Last, this rule change for the net thickness of web stiffeners and brackets of the primary supporting members is in line with the current practice. 2.5 KC 414 Application of structural arrangement principles Rule Change description The structural arrangement principles defined in Chapter 3 Section 6 are applicable to the complete hull structure except superstructures and deckhouses; in addition several references in Chapter 3 Section 6 are made to areas outside the cargo holds. Specific additional requirements for other areas (fore part, aft part, machinery space, superstructures, deckhouses, hatch covers, openings) are found in Chapter 9. The scope of application of the general principles in Chapter 3 Section 6 is extended to the complete hull structure and references are made to specific requirements from Chapter Applied change Chapter 3 Section 6 [1] The article is changed to extend the scope of this section to the whole hull structure, except deckhouses or superstructures. Supplementary requirements of Chapter 9 are mentioned Chapter 3 Section 6 [7] The title of this article is changed to indicate the limitation of its scope to the cargo hold area. 10 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

59 Chapter 3 Section 6 [8] The title of this article is changed to indicate the limitation of its scope to the cargo hold area Impact on scantling Under the assumption that none of the requirements in Ch. 3 Sec. 6 with respect to end brackets, tripping brackets, steel grade has been fulfilled outside the cargo hold area previously, one may expect a minor scantling increase. In general the scantling impact can be ignored. 2.6 KC 417 Net thickness of non-tight bulkhead stiffeners not acting as pillars Rule Change description The requirement in the last sentence of Chapter 3 Section 6 [10.5.1], that the net thickness of bulkhead stiffener is not to be less than the minimum thickness required for the considered bulkhead plate, is quite severe, especially for the stiffener with Bulb, Angle or T shape sections. In order to investigate the net thickness of web stiffeners and brackets, corresponding data is gathered, which includes 4 types of non-csr Bulk Carriers, Handysize, Handymax, Panamax and Capsize, 16 ships totally, all of them are well in service. According to the investigation about the net thickness of bulkhead stiffeners on non-tight bulkheads not acting as pillars such as wash bulkheads, it is found that the net offered thickness of bulkhead stiffeners for some bulk carriers are thinner than the minimum required net thickness of the bulkheads. So, a proposed Rule Change is carried out for the requirement in Chapter 3 Section 6 [10.5.1]. The investigation data are summarized in the following Table 5 and Figure 1. Table 5 KC 417 Investigation data about the net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars Technical Background of Rule Change Notice 1 July 2010 edition 11 / 63

60 Figure 1 KC 417 Comparison for the net offered thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars and net min required thickness in CSR-BC and the proposed Rule Change The conclusion is following: The net offered thickness of bulkhead stiffener in three types, Handysize-1, Panamax-1 and Capesize-1, is less than both the requirements in Chapter 3 Section 6 [10.5.1] and the proposed Rule Change. Based on the above investigation, it is reasonable and realistic that the requirement in the last sentence of the last paragraph of Chapter 3 Section 6 [10.5.1] is modified as that the net thickness of bulkhead stiffeners are not to be less than ( L 2 ), in mm Applied change Chapter 3 Section 6 [10.5.1] The last sentence of the last paragraph is to be changed to The net thickness of bulkhead stiffeners are not to be less than the minimum net thickness defined in Chapter 6, Section 2, [2.2.1], i.e L 2, in mm Impact on scantling There are some changes on the scantlings of bulkhead stiffeners of non-tight bulkheads not acting as pillars before and after this rule change. For ships with rule length L from 90m to 216m, the required net thickness of the proposed Rule Change is less than that before. For ships with rule length L from 217 to 249m, there is no change before and after the proposed Rule Change. For ships with rule length L 250m or above, the required net thickness of the proposed Rule Change is greater than that before. The comparison data are summarized in the Table 6 and Figure 2, 12 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

61 Table 6 KC 417 Comparison for the required net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars in CSR and the proposed Rule Change Technical Background of Rule Change Notice 1 July 2010 edition 13 / 63

62 Figure 2 KC 417 Comparison for the required net thickness of bulkhead stiffener of non-tight bulkheads not acting as pillars in CSR and the proposed Rule Change 2.7 KC 494 Transverse and longitudinal watertight bulkheads minimum net thickness Rule Change description Chapter 9 Section 1 Table 1 and Chapter 9 Section 2 Table 1 give the minimum net thicknesses for plating of several structural members. These tables are extracts of Table but without values for the transverse and longitudinal watertight bulkheads. The corresponding lines are added and the same minimum net thickness as in table is required Applied change Chapter 9 Section 1 [Table 1] The line corresponding to the transverse and longitudinal watertight bulkheads is copied from Chapter 6 Section 1 Table 2 to Chapter 9 Section 1 Table Chapter 9 Section 2 [Table 1] The line corresponding to the transverse and longitudinal watertight bulkheads is copied corresponding line from Chapter 6 Section 1 Table 2 to Chapter 9 Section 2 Table Impact on scantling This correction is adding a minimum required net thickness. As the final net thickness to consider is greater, there is no impact on scantling or on steel weight. 14 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

63 2.8 KC 524 Fore Part structures in flooding condition Rule Change description Ships are to be designed to have sufficient reserve strength to withstand in flooding scenarios as a functional requirement. However, there is no specific paragraph in fore part referring to need of scantling assessments in case the fore part is arranged with floodable spaces. The proposed amendment is to clarify that Chapter 9, Section 2, [1.1.2] is also applicable to the fore part Applied change Chapter 9, Section 1, [1.1.2] The new paragraph Chapter 9, Section 1, [1.1.2] is added for calculating the scantlings in flooding conditions Impact on scantling There is no change in terms of steel weight by comparing that before and after the proposed Rule Change since the required values is smaller than the one of existing design in general. 2.9 KC 565 Scantlings of transverse vertically corrugated watertight bulkhead separating cargo holds for flooded conditions Rule Change description The proposal is to clarify the pressure and force to be considered when determine the scantlings of transverse vertically corrugated watertight bulkhead separating cargo holds for flooded conditions. In the calculation, not only the resultant pressures and forces but also the pressures and forces in flooded empty holds should be considered Applied change Chapter 6 Section 1 [3.2.3] Cross reference of Ch 4, Sec 6, [3.3.6] is added into the definition of p Chapter 6 Section 2 [3.6.1] Cross reference of Ch 4, Sec 6, [3.3.6] is added into the definitions of F and p G. Technical Background of Rule Change Notice 1 July 2010 edition 15 / 63

64 2.9.3 Impact on scantling This amendment gives more precise application of resultant pressure and force when determine the scantlings of transverse vertically corrugated watertight bulkhead separating cargo holds for flooded conditions but is not changing the approach. There is consequently no impact on scantling or steel weight KC 567 Bilge definition Rule Change description The definition of the bilge area is not given in the current CSR BC and as shown in Figure 3 below, it may lead to ambiguities particularly in fore and aft parts where the curved part of the side shell is wider than in the central area. The CSR OT in 4/ gives in turn a concrete definition of the bilge plating within the 0.4L amidships area and outside. As tankers and bulkers have similar hull shapes, proportions and coefficients and are submitted to similar sea pressures, it is possible to use a similar definition in CSR BC than in CSR OT. On this basis, the proposed definition distinguishes: the cylindrical part of the hull where the bilge is clearly defined The other parts where a maximum height already defined in CSR OT is considered in order to limit the bilge extent even if the curved plating is continuing above. Figure 3 KC 567 ambiguous bilge area in the fore part. The requirements for the aft and fore parts are to be applied in addition to the ones triggered by this definition; this applies to the strengthening of the flat bottom area in the fore part in Chapter 9 Section 1 [5.2]. Consequently, the term flat is not used anymore in Chapter 9 Section 1 for avoiding misunderstandings, as the current requirements give a clear definition of the reinforced area Applied change Chapter 1 Section 4 [3.22] and [3.22.1] A new sub-article and a new requirement are added to incorporate the definition of the bilge plating Chapter 9 Section 1 [5] [5.1.1] [5.2.1] [5.3.1] [5.3.2] The word flat is removed from the titles or the requirements. 16 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

65 Impact on scantling Cylindrical area On the cylindrical part, the bilge definition is matching the current practice and therefore, there is no impact on scantling or on steel weight Forward to the cylindrical area The rule change does not change the definition of the areas to be reinforced in the forward area. There is consequently no impact on scantling or on steel weight KC 568 Strength of Rudder Body Rule Change description The reason to change is to make the rules in line with URS Applied change Chapter 10 Section 1 [5.1.4] Allowable bending and Von Mises stress is changed to be in line with URS Impact on scantling The reduction of allowable stress will result in a minor increase in scantlings KC 571 Cargo mass in fatigue stress assessment Rule Change description For fatigue strength assessment, the cargo density used is to be as much realistic as possible. Therefore, the cargo density according to Chapter 4 Appendix 3 should be used for fatigue strength assessment not only by direct analysis specified in Chapter 8 Section 3, but also simplified method specified in Chapter 8 Section 4 [2.3.5] Applied change Chapter 8 Section 4 [2.3.5] In the definition of the inertial pressure due to the dry bulk cargo, the value of the cargo density to be used is added. Technical Background of Rule Change Notice 1 July 2010 edition 17 / 63

66 Impact on scantling There is no impact on scantling or steel weight as this change is intended to clarify the load case to consider in fatigue strength assessment KC 590 Effective breadth of attached plating for primary supporting members Rule Change description The definition of the effective breadth of attached plating of primary supporting members given in Chapter 3 Section 6 [5.4.1] does not consider the spacing and is in contradiction with the definition given in Chapter 6 Section 4 [Symbols] which refers to Chapter 3 Section 6 [4.3.1]. The definition given in Chapter 3 Section 6 [4.3.1] is used. This change is made for clarifying the requirements Applied change Chapter 3 Section 6 [5.4.1] The last sentence of the item is modified in order to refer to Chapter 3 Section 6 [4.3.1] for the determination of the effective breadth of the attached plating Impact on scantling In Chapter 6 Section 4 [Symbols], the effective breadth b p to consider for primary supporting members is already defined as per Chapter 3 Section 6 [4.3.1]. For ships having a length L less than 150m, the requirements in Chapter 6 Section 4 are thus made in accordance with this definition. For ships having a length L greater than 150m, the scantlings of primary supporting members are to comply with the results of direct calculations that are not concerned by this definition. There is consequently no impact on scantling or steel weight KC 630 Deck between hatches Rule Change description Firstly, regarding the structural arrangement, the definition of the beams under consideration in this item is clarified: these are hatch end beams and cross deck beams. In addition, the term bulwark is replaced by deck side in order to match the designs where a bulwark is not fitted. Secondly, as some designs are not able to comply with these prescriptive requirements, the use of a direct strength analysis as per Chapter 7 in these rules is now allowed Applied change Chapter 3 Section 6 [9.2.3] First change: the general term beams is replaced by hatch end beams and cross deck beams and the term bulwark is replaced by deck side. Second change: addition of the sentence which allows the use of direct strength analysis for the arrangements that do not comply with the prescriptive requirements in this sub-article. 18 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

67 Impact on scantling The first correction has no impact on scantling. The designs concerned by the direct strength analysis are supposed to be made of less structural elements than those complying with the prescriptive requirements in this item. Consequently, this change does not increase the steel weight induced by this requirement. In addition, the use of a direct strength analysis is not supposed to affect the scantlings KC 653 Bow flare area pressure Rule Change description In Ch 4, Sec 5, [4.1.1], bow flare area pressure is specified but calculation point and draft to be considered are not clearly specified. According to the background of this requirement, the following assumptions are to be considered for this requirement: (1) Hydrostatic pressure and hydrodynamic pressures among load cased H, F, R and P, calculated in normal ballast condition (2) T B, minimum ballast draught at midship in normal ballast condition as specified in Ch 1, Sec 4, [2.1.1] is to be considered for the calculation of hydrostatic pressure and hydrodynamic pressures (3) Any considered point of the hull is to be used for a calculation point To be in line with the above, the definitions of hydrostatic pressure and hydrodynamic pressures are modified Applied change Chapter 4 Section 5 [4.1.1] The definitions of hydrostatic pressure and hydrodynamic pressures are modified in order to make the calculation points and draught to be considered clear Impact on scantling This change is intended to clarify the definitions of hydrostatic pressure and hydrodynamic pressures and does not include any scantling requirement. This change does not affect the scantlings or the steel weight. Technical Background of Rule Change Notice 1 July 2010 edition 19 / 63

68 2.16 KC 654 Primary supporting members under flooded condition Rule Change description Under flooding condition, the scantlings of collision bulkhead and other watertight boundaries are calculated according to Chapter 6, Section 1, [3.2.2] for bulkhead plating and Chapter 6, Section 2, [3.2.5] for ordinary stiffeners. However, there is no specific requirement for the primary supporting members (PSM). Hence a new requirement for PSM s has been developed based on similar method as for ordinary stiffeners considering the parameter α. The α parameter set to 1.15 leads to lower values of net section modulus and net shear sectional area lower than in intact condition (see Chapter 6, Section 4, [2.6.3]) Applied change Chapter 6, Section 4, [1.6.1] A new paragraph is added giving a reference to flooding requirements for PSM Chapter 6, Section 5 The new section is added for calculation of scantlings for primary supporting members under flooded conditions. The formula is based on similar requirement given in Chapter 6, Section 2, [3.2.5] for ordinary stiffeners Impact on scantling The new requirement will have an impact on watertight structure which is not normally subject to liquid load. Typical examples are collision bulkhead, engine room bulkhead and other watertight boundaries which is not part of a liquid tank boundary. There is little or no change in terms of steel weight by comparing that before and after the proposed Rule Change since the required values is in general smaller than the one of existing design in general. Details of calculation results can be found in Annex I KC 666 Deck Primary Supporting Members Rule change description As stated in Pt. 9 Sec. 1 [4.4.4] and Pt. 9 Sec. 2 [4.3.4], scantlings of deck PSM in fore and aft peak areas are currently to be determined according to Ch. 6, Sec. 4. This has created some confusion in application of scantlings requirements for PSM in fore and aft peaks which are different from those of side PSM as shown in the following table. This rule change is to align the scantlings requirements of deck PSM in fore and aft peaks to those of side PSM. Reference is made to the TB Document of CSR 2006 edition. 20 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

69 Table 7 KC 666 Comparison of current scantlings requirements for PSM Item Min. thickness Section modulus Requirement Web thickness of PSM w = 2 ( p + p ) s 3 S S W mλ R Shear area 5( ps + pw ) A sh Y τ sinφ a 10 s Cargo area (Ch.6. Sec.4) 2 Deck Fore and aft peaks (Ch.9 Sec.1 & Sec.2) Side t = 0.6 L t = 0.7 L2 (*1) t = 0.7 L2 (*1) λ S = 0.8 m =10 λ S = 0.8 m =10 = τ a = 0.4RY τ a = 0.4RY λ S = 0.9 m = 10 (*2) RY τ a = 3 (*1) Minimum web thickness for PSM is stated in fore peak area. In aft peak area, similar requirement applies only to floors. (*2) The m-coefficients stated in Ch.9 Sec.1 and Sec.2 [Symbols] are specified only for stiffeners Applied change Chapter 9 Section 1 [Symbols] 1. The m-coefficient is specified explicit for PSM. 2. Span and spacing are re-defined to cover both stiffeners and PSM Chapter 9 Section 1 [4.4.4] 1. The scantlings formulae and allowable stresses of deck PSM in fore peak area are specified explicit in the new Table The allowable normal stress and the allowable shear stress are taken from ordinary stiffeners same as side PSM. 3. Reference to bow flare area pressure in [3.3] is taken out which is not relevant for deck PSM. 4. For complex deck structure, opening for a direct calculation is included to replace the scantlings formulae Chapter 9 Section 2 [Symbols] 1. The m-coefficient is specified explicit for PSM. 2. Span and spacing are re-defined to cover both stiffeners and PSM Chapter 9 Section 2 [4.3.4] 1. The scantlings formulae and allowable stresses of deck PSM in aft peak area are specified explicit in the new Table The allowable normal stress and the allowable shear stress are taken from ordinary stiffeners same as side PSM. For complex deck structure, opening for a direct calculation is included to replace the scantlings formulae Impact on scantlings According to the rule change, allowable stresses of deck PSM in intact conditions will increase in fore and aft peak areas, i.e., normal stress by +11% and shear stress by +44%. In addition, requirements in testing conditions are introduced for deck PSM. Consequently, required scantlings of deck PSM in intact Technical Background of Rule Change Notice 1 July 2010 edition 21 / 63

70 conditions will be reduced as shown in the Appendix. Impact on steel weight is not expected because actual scantlings are normally above the requirements KC 758 Height of double bottom Rule Change description The last version of the SOLAS Ch. II-1, Part B-2, Reg. 9 (2) entered in application in January 2009 is to be considered and thus replaces the first paragraph of the requirement Applied change Chapter 3 Section 6 [6.1.3] The text of the first paragraph is replaced by an adapted version of the herein referenced SOLAS regulation Impact on scantling The main change induced by this modification is the addition of a lower limit of 0.76m for the doublebottom height. It can be considered that this lower limit is far below the current practices, even in the moulded parts of the hull. There is consequently no impact on steel weight or on scantling KC 759 Spacing of solid floors Rule Change description In Ch.9 Sec.1 [2.3.2], prescriptive requirement is given with respect to spacing of solid floors in case of longitudinal framing. However, it was agreed in KC 759 that a larger spacing may be acceptable, when the bottom structure is verified by FEA deemed appropriate by the Society Applied change Chapter 9 Section 1 [2.3.2] In the second paragraph which is applicable for longitudinal framing, a new sentence is inserted so that a larger spacing of solid floors may be acceptable based on FEA Impact on scantling In general the scantling impact can be ignored. 22 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

71 2.20 KC 760 Depth of web stiffener Rule Change description The requirement to depth of web stiffeners is based on a simplified assessment of the buckling strength of the stiffener. The formulation is derived based on the assumptions that the web stiffener is of flat bar type, and that the web stiffener length is approximately the same as the shorter side of the web plate. The requirement is a simple, conservative means to proportion web stiffeners, however, it has been found to be too conservative for cases where the above mentioned assumptions are not satisfied. Based on the above, it was agreed in KC 760 that Ch3 Sec 6 [5.2.1] is only applicable to web stiffeners of flat bar type. The rule text has been modified accordingly. As an alternative to the simple conservative descriptive requirement, the rule text has been amended to allow a more advanced buckling check in accordance with Ch6 Sec3, given that the slenderness requirement in Ch 6 Sec 2 [2.3.1] and specific web stiffener requirements in Ch 6 Sec 2 [4] are satisfied. The rule change as described above is also to be applicable for non-tight bulkheads Applied change Chapter 3 Section 6 [5.2.1] It is clarified that the requirement to depth of web stiffener depth is only applicable to flat bar type stiffeners. The rule text has been amended to allow a more advanced buckling check in accordance with Ch6 Sec3. Chapter 3 Section 6 [10.5.1] It is clarified that the requirement to depth of web stiffener depth is only applicable to flat bar type stiffeners. The rule text has been amended to allow a more advanced buckling check in accordance with Ch6 Sec Impact on scantling The rule proposal is made to align the Rules with well proven industry practice. Impact on steel weight is considered negligible KC 764 Connection ends of web stiffeners Rule Change description The formula for evaluating the stress at the ends of web stiffeners of primary supporting members in water ballast tanks comes from the NK rules Guidance Part C C (1) of the 2010 edition in which the coefficient of 1.1 is a Correction coefficient for corrosion. As the CSR BC uses the net scantling approach, this coefficient should not be considered and the formula is amended accordingly. Technical Background of Rule Change Notice 1 July 2010 edition 23 / 63

72 Applied change Chapter 6 Section 2 [4.1.3] The coefficient 1.1 is removed from the formula giving the stress Impact on scantling Removing this coefficient decreases the calculated stress of 9%. In turn, this allows the stress range σ to be increased of 10% for the same design. This stress range σ is a function of several dimensions and of the stiffening arrangement through the dynamic load W. In addition, this requirement is intended to ensure that the connection of stiffeners to longitudinals have sufficient fatigue strength KC 768 & KC 800 Ultimate Strength in Lateral Buckling Mode Rule Change description Ch. 6 Sec. 3 [4.2.2] Relevant KC ID : 768 In Ch.6 Sec.3 [4.2.2], it is not clear about how to calculate net section modulus of stiffeners snipped at both ends. When a stiffener snipped at both ends is under compression, compressive stress is induced at the attached plate by a moment due to eccentricity of a compression force off the neutral axis of the stiffener. Consequently the net section modulus is in general calculated at the attached plate. Figure 4 KC 768 & 800 Moment and forces on a snipped stiffener in lateral buckling. However, when a stiffener snipped at both ends is subject to lateral pressure acting on the stiffener side, and when M 1 induced by lateral pressure is larger than M 0 induced by the deformation, the flange is in compression. Therefore the net section modulus is calculated at the flange. When a stiffener snipped at both ends is subject to lateral pressure acting on the stiffener side, M 0 and M 1 are in opposite direction. Therefore the deformation w shall be the absolute value of difference between w 0 and w Ch. 6 Sec. 3 [4.2.3] In Ch.6 Sec.3 [4.2.3], it is not clear about whether this requirement is applicable to stiffeners snipped at both ends or not. It is clarified by KC800 that Ch.6 Sec.3 [4.2.3] is applicable to stiffeners other than snipped at both ends. 24 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

73 Applied change Ch. 6 Sec. 3 [4.2.2] In the definition of net section modulus W st, it is clarified about how to calculate for stiffeners snipped at both ends. In the definition of deformation w, it is clarified about how to calculate for stiffeners snipped at both ends Ch. 6 Sec. 3 [4.2.3] A note is inserted in order to clarify that Ch.6 Sec.3 [4.2.3] is applicable only to stiffeners other than snipped at both ends Impact on scantling The scantling impact is negligible in terms of steel weight KC 773 Corrosion addition of longitudinal stiffeners Rule Change description When a longitudinal stiffener is concerned by different corrosion additions (e.g. the face plate of the stiffener is within the 3m below the tank top and the web plate is outside this area), the severest corrosion addition is to be applied. This principle is not easy to apply, particularly for prescriptive softwares, as the stiffener s properties are evaluated on the basis of the coordinate of the connection point between the stiffener and the attached plating. The same approach is kept for the corrosion addition to consider for a longitudinal stiffener: it is the value at the coordinate of its connection point to the attached plating Applied change Chapter 3 Section 3 [1.2.1] A sentence is added to specify that the corrosion addition of a longitudinal stiffener is based on the coordinates of its connection point to the plating Impact on scantling There is no impact on the dimensions obtained from the prescriptive approach, due to the net scantling approach used in the CSR The impact on the steel weight is not evaluated KC 793 Cofferdam arrangement Rule Change description The requirement in Chapter 2 Section 2 [2.1.3] is about arrangement for fire safety. This is also covered by SOLAS in Chapter II-2 with extensive details. Therefore, this requirement is not needed in the CSR BC and is deleted from it. The subsequent requirement is renumbered. Technical Background of Rule Change Notice 1 July 2010 edition 25 / 63

74 Applied change Chapter 2 Section 2 [2.1.3] This requirement is removed: the text is replaced by void Impact on scantling SOLAS requirements about fire safety are applicable and overrule the deleted requirement. There is consequently no impact on steel weight or scantling KC 798 SOLAS Subdivision arrangement Rule Change description The previous requirement of SOLAS Chapter II-1, Part B, Regulation 11 (cf. App.3.2) is changed to the new version of SOLAS Ch. II-1, Part B-2, Reg. 12 (9), (cf. App.3.3) applicable from January Before January 2009, in SOLAS Chapter II-1, Part B, the arrangement of Peak and machinery space bulkheads, shaft tunnels, etc. was declined in regulation 10 (7) (cf. App.3.1) for passenger ships and in regulation 11 (8) for cargo ships. The main difference was the inclusion of an afterpeak bulkhead in the case of passenger ships and of specific arrangement principles. While the current reference in CSR BC Chapter 2 Section 1 [3.1.1] is the correct one, the text is from the regulation 10 (7). The new version in regulation 12 (9) has merged the former two ones and thus is to be adapted to the case of bulk carriers. The relevant part of this new version of the requirement is copied in the CSR BC text and the last sentence of the requirement regarding the after peak bulkhead is removed as the new SOLAS regulation makes it clearly intended to passenger ships only Applied change Chapter 2 Section 1 [3.1.1] The text of this requirement is changed to the relevant parts of the new text of SOLAS Ch. I-1, Part B-2, Reg. 12 (9). The last sentence of the initial text is removed. The symbol L is replaced by the symbol L LL for the consistency with the other requirements in the CSR BC. As this is not the complete SOLAS text, the reference to the SOLAS regulation is not added before and the text is not in italic. The reference to the SOLAS regulation is to be found through the technical background Impact on scantling The new text gives more precise requirement for the after peak bulkhead but is not changing the approach. There is consequently no impact on steel weight or scantling. 26 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

75 2.26 KC 836 Side bottom girders in way of machinery seatings Rule Change description In KC 836 it was agreed that the requirement that side bottom girders in way of machinery seatings have to be tapered for at least three frame spacings forward of the E/R bulkhead is too rigid. In order to ensure design flexibility, it was agreed that the requirement should be replaced by a more general requirement to structural continuity Applied change Chapter 9 Section 3 [2.1.5] The requirement in the fourth paragraph that side bottom girders in way of machinery seatings have to be tapered for at least three frame spacings forward of the E/R bulkhead has been replaced by a more general requirement to structural continuity Impact on scantling In some cases tapering brackets in the double bottom may be avoided. Impact on steel weight is considered negligible KC 848 Harmonisation of welding of abutting plates below the waterline Rule Change description The requirements of CSR BC for the welding of abutting plate panels forming boundaries to sea water below the summer waterline differs from those of CSR OT: In CSR BC Chapter11 Section 2 [2.4.1], a full penetration weld is to be always applied. In CSR OT 6/ (f), full penetration welding is to be applied only for plate panels having a gross thickness less than or equal to 12mm. For thicker plates, partial penetration welding is allowed, provided the root face length is smaller than the third of the gross thickness of the plates. Industry is also reporting that full penetration welding is unpractical and unnecessary for thick plates (i.e. having a gross thickness greater than 12mm). The current requirements of CSR BC are harmonised with those of CSR OT in order to meet the current practices of industry Applied change Chapter 11 Section 2 [2.4.1] In the last item of the list: The lower limit of 12mm in as-built thickness is added for the application of the full penetration welding. The application of deep penetration welding to thicker plates is added with a reference to Fig.2 for the definition of the root face. Technical Background of Rule Change Notice 1 July 2010 edition 27 / 63

76 Deep penetration welding is considered in Chapter11 Section 2 [2.5] but in a general manner, without a list of applicable items. Therefore, it has been considered preferable for the sake of the reader to keep the deep penetration welding requirement in the full penetration section, for this particular kind of plates Impact on scantling The rules requirement is about the practice of the industry. The resulting differences on scantling or steel weights are not evaluated KC 854 Members subjected to fatigue strength assessment Rule Change description Regarding Tab 1 in Chapter 8, Section 1, the intent at the time of development of the CSR-BC was not to check the inner bottom only, but the whole connection of inner bottom with sloping and/or vertical plate of lower stool, which includes all the plates. The whole connection means the connection of plating members of inner bottom, side of lower stool, girders and floors in DB and diaphragms in lower stool. In addition, it is to be noted that, when making fatigue assessment of such connection, if fatigue problems are found in any of the above plating members, then reinforcements are to be considered for all the concerned plating members. It means that Table 1 concerns all the plating members involved in the inner bottom/lower stool connection and not only the inner bottom plating Applied change Chapter 8 Section 1 [1.3.1] The text of this item is modified to indicate that all the connected members are to be checked and that all connected members are to be reinforced when a problem is found. Table 1 is kept as it is Impact on scantling The applied modification is only intended to enforce the understanding of the readers. There is no modification on the scantling or the steel weight KC 903 Collision Bulkhead Rule Change description In order to be in line with the SOLAS requirements, the former text from SOLAS Ch. II-1, Part B, Reg. 11, is replaced by the text from SOLAS Ch. II-1, Part B-2, Reg.12 (1) which was previously the Annex 2 of MSC resolution 216(82) Applied change Chapter 2 Section 1 [2.1.1] The text of this item is changed in order to be inline with the SOLAS text. The initial term Administration in the SOLAS text is replaced by Society and is not in italic in order to identify the change. 28 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

77 Impact on scantling The change in the SOLAS text is mainly about the arrangement of this collision bulkhead. There is no defined scantling. The possible impact on the steel weight is not evaluated KC 938 Harmonisation of tapering between abutting plates Rule Change description Tapering is required between plates of different thicknesses in both CSR BC and CSR OT: In CSR BC Chapter 11 Section 2 [2.2.2], the criterion for applying tapering is a difference in as-built thickness equal to or greater than 4mm. In CSR OT 6/ , the criterion for applying tapering is a difference by more than 4mm. In order to harmonise these criteria, the CSR BC requirement is modified in order to consider a difference in thickness between the abutting plates strictly greater than 4mm Applied change Chapter 11 Section 2 [2.2.2] In the first sentence the term equal to or greater than is replaced by greater than Impact on scantling The rules requirement is about the practice and does not give dimensions of the tapering. The resulting differences on scantling or steel weights are not evaluated KC 966 Load Testing Height Rule Change description According to the comment from industry and further investigations, the conclusion is that 0.9 m head of water above top of hatch is irrational to carry out the structural test of ballast hold. It is very difficult to keep the testing load height specified because the hatch cover of a ballast hold is generally not watertight but weathertight. Ballast hold is subject to higher liquid pressure in rough sea and the test itself is not intended for the hatch covers. Furthermore, IACS is developing a new version (Rev.4, July 2011) of the UR S14 Testing Procedures of Watertight Compartments on the basis of a guideline (cf. App.4.1) for tight test of compartments. This document is attached in Appendix 3. In this new version of UR S14, the load test height for ballast hold is not 0.9m above top of hatch but top of hatch coaming. This does not apply to the overhead of 0.9 m used in Chapter 4, Section 6 Table 2, kept as a design overhead. In addition, the definitions of the coordinates are clarified in Chapter 3 Section 6 Table Applied Changes Chapter 3 Section 6 [4.1.1] Table 2 In the last line of the table, containing the definition: In the z ml definition, the term margin line is changed to the bulkhead deck at side Technical Background of Rule Change Notice 1 July 2010 edition 29 / 63

78 In the z h definition, the term hatch is changed to hatch coaming Chapter 11 Section 3 [3.1.1] Table 1 The 0.9m head of water above the highest point of tank in line 4 column Structural test pressure is replaced by the head of water above top of hatch coaming ; Impact on scantling Chapter 3 Section 6 [4.1.1] Table 2 The changes are clarifying the terms used in order to match the current practice. There is consequently no impact on scantling or steel weight Chapter 11 Section 3 [3.1.1] Table 1 In general the scantling impact can be ignored. The main purpose of structural test is not to determine a scantling of structural members but to check the soundness of the structure. Ballast hold is subject to higher liquid pressure in rough sea and scantling is determined by pressure in sea going condition KC 1004 Bulb stiffener s properties Rule Change description In some cases, the use of an equivalent angle section for the determination of the characteristics of a bulb stiffeners leads to significant differences with the exact values. For example, the inertial moment about the horizontal neutral axis of a bulb 200x10 is: Equivalent angle section: I = 1019cm 4 Direct method: Holland Profile: I = 1017cm 4 Russian Profile: I = 1083cm 4 The use of values obtained by direct methods is requested and in addition, the harmonisation of the two set of CSR rules is needed Applied Changes Chapter 3 Section 6 [4.1.1] A sentence allowing the use of exact values for the dimensions and properties of a bulb section is added to the text. The use of an equivalent angle section is kept Impact on scantling As the mass of the bulb profile should be given by the manufacturer and so available to the designers, there is no impact on the steel weight. 30 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

79 2.33 KC 1009 Single side and double side definitions Rule Change description The SOLAS XII Reg.1 has been updated with definitions of single side skin and double side skin bulk carriers. As some requirements in the CSR BC are specifically intended to each kind of bulk carriers, these definitions are added to the rules. It is to be noted that these definitions are in addition to the definition of a CSR bulk carriers as per Chapter1 Section 1 [1.1] SOLAS definitions Definitions of bulk carriers, single side skin and double side skin bulk carriers are given by IMO in SOLAS regulations and by IACS in UR Z and partially in the CSR BC (cf. Appendix 3). SOLAS Chapter IX, Regulation 1 (6.) defines the bulk carriers in terms of: Intended cargoes: dry cargoes in bulk; General design of the cargo space: single deck, top-side tanks, hopper side tanks. SOLAS Chapter XII, Regulation 1 (1. to 4.) defines the bulk carriers in terms of: Intended cargoes: dry cargoes in bulk; Single-side skin: any part of a cargo hold is bounded by the side shell cargo holds bounded by a double-side skin with the following criterion on its width: Table 8 KC 1009 Double-side skin width equivalent to a single-side skin as per SOLAS XII. Width of the double-side skin Construction period mm Before 1 st January mm Between 1 st January 2000 and 1 st July 2006 Double-side skin when the ship side is made of the side shell and a longitudinal bulkhead connecting the double-bottom to the deck, including hopper side and top-side tanks if any. The resolution MSC.79(70) refers to the resolution 6 of the SOLAS Conference 4 held in 1997 about the interpretation of the definition of a bulk carrier. In its resolution 6, the SOLAS Conference 4 merged the definition of Chapter IX Regu1ation (6.) and Chapter XII Regulation 1 by applying the general design to any bulk carrier IACS definitions UR Z defines a bulk carrier similarly as SOLAS Chapter IX Regulation 1 (6.), cf UR Z and UR Z define a double skin bulk carrier a bulk carrier where all cargo holds are bounded by a double-side skin, regardless of the width of enclosed space CSR BC application As per CSR BC Chapter 1 Section 1 [1.1.1], the CSR BC is applicable to bulk carrier ships contracted for construction on of after 1 st April SOLAS XII Reg.1 (8) defines the construction as the date when the keel is laid or when the ship is at a similar stage of construction. Technical Background of Rule Change Notice 1 July 2010 edition 31 / 63

80 Analysis For bulk carriers contracted for construction after the 1 st July 2006, there is no more applicable width requirement for the consideration of a double-side skin design. The definitions given by IACS are including the SOLAS definitions and interpretations in terms of Intended cargoes: dry cargo in bulk. General design of the cargo space: single deck, top-side tanks, hopper side tanks. Single-side skin: any part of a cargo hold is bounded by the side shell. Double-side skin when the ship side is made of the side shell and a longitudinal bulkhead connecting the double-bottom to the deck, including hopper side and top-side tanks if any. CSR BC already uses the above definition of a bulk carrier in terms of intended cargoes and general design. In addition, it allows hybrid designs where among possible designs, holds of single skin and double skin constructions can be mixed. In order to cover all the possibilities, the definitions single-side skin constructions and double-side skin constructions are added and can be applied to each hold. The definitions of single-side skin and double-side skin constructions are as follow: Single-side skin construction All the cargo holds are bounded by the side shell between the hopper plating or the inner bottom and the top-side tank plating or the deck. Double-side skin construction All the cargo holds are bounded by a double-side, including the hopper tank and the top-side tanks when fitted. Notes: Between 1 st April and 1 st July 2006, width limit of 1000 mm for double-side skin is applicable and contradicts the above definitions. Considering that this sibling period is short and that no problem has been reported, it is decided to not consider this specific case. These definitions are not considering the possible needs for access to the double-side space. The provisions and technical specifications given SOLAS Chapter II-1 Regulation 3.6 are applicable and will govern the dimensions and access equipments of the double side space. It is therefore not needed to add any mention of it in the definition of a double-side skin bulk carrier. In addition, the terms bulk carriers are replaced accordingly in other locations in the text Applied Changes Chapter 1 Section 4 [3.21] [3.21.1] [3.21.2] The new article [3.21] is added for the definitions of holds of single side skin and double side skin constructions. It contains the following new sub-articles: [3.21.1] for the single side skin bulk carriers, [3.21.2] for the double side skin bulk carriers Chapter 2 Section 3 [2.8] [2.9] [2.10] [2.11] The words single side bulk carriers and double side bulk carriers are replaced by holds of single side skin construction and holds of double side skin construction respectively in the different titles Chapter 3 Section [5] [1.3.3] [1.3.4] The words single side bulk carriers and double side bulk carriers are replaced by holds of single side skin construction and holds of double side skin construction respectively in the different requirements. 32 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

81 Chapter 5 Section 1 [Table 1] The words single side ships and double side ships are replaced by single side skin construction and double side skin construction respectively in the first column of the table. This does not affect the formulas or the approach Chapter 7 Section 3 [Table 2] The words bulk carriers and bulk carriers are replaced by skin construction and skin construction respectively in the second column of the table. This does not affect the formulas or the approach Chapter 8 Appendix 1 [2.5.1] The words single side bulk carriers and double side bulk carriers are replaced by holds of single side skin construction and holds of double side skin construction respectively in the requirement Impact on scantling This change is intended to clarify the definition of bulk carriers and does not include any scantling requirement. This change does not affect the scantlings or the steel weight KC 1082 Minimum bow height Rule Change description The reason to change is to make the rules in line with ILLC (Resolution MSC.223(82)) Applied change Chapter 2 Section 2 [5.1.1] The definition of draught T 1 is to be replaced by the one as specified in ILLC. (Resolution MSC.223(82)) Impact on scantling There is no impact on scantling. Technical Background of Rule Change Notice 1 July 2010 edition 33 / 63

82 Appendix 1. KC666 related documents App.1.1. Introduction Scantlings of deck PSM in fore and aft peaks have been compared taking actual bulk carriers in three representative size groups as example, i.e.handymax, Panamax and Capesize. Table 9 KC 666 Main characteristics of typical bulk carriers Ship size Capacity Applied Rules Freeboard type Handymax 55,000 dwt CSR B Panamax 80,000 dwt Non-CSR B-60 Capesize 180,000 dwt CSR B-60 App Comparison of scantlings With a typical deck transverse, the following requirements are calculated and compared against actual scantlings. t = 0.7 L 2 Ps 3 w = 10 10σ 5Ps A sh = τ sinφ Minimum web thickness of deck PSM (fore peak only) 2 Section modulus of deck PSM Shear area of deck PSM App Allowable stresses As discussed in KC 666, allowable stresses for PSM are different between cargo area and fore and aft peak areas and between side PSM and deck PSM. For PSM on side structure, allowable stresses are taken from those of ordinary stiffeners as explained in the TB document for CSR 2006 edition. This rule change is to align the requirements for deck PSM and side PSM in line with ordinary stiffeners. In connection with this rule change, allowable stresses are newly introduced for testing conditions which are not specified in the cargo area. Table 10 KC 666 Allowable stresses Condition Normal stress σ Shear stress τ Intact condition Testing condition Current rules New rules σ 0.8R Y 0.9RY σ σ 1.05RY τ 0.4R Y τ 3 τ.05r 3 R Y 1 Y 34 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

83 App.1.2. Fore peak area App Target deck structure in fore peak area Typical deck transverse on fore peak tank top is selected as illustrated below in Table 11 and Figure 5. Scantlings of deck PSM on the forecastle deck are determined by Ch.9 Sec.4 and therefore are kept outside the scope of this study. Table 11 KC 666 Fore peak arrangements for typical bulk carriers Ship size Capacity Freeboard type Arrangement 1) Handymax 55,000 dwt B Type A Panamax 80,000 dwt B-60 Type B Capesize 180,000 dwt B-60 Type B Fcle deck Upp deck Pillars Bosun store Fcle deck Upp deck Pillars Bosun store Void space Target Target FPT FPT Type A Type B Figure 5 KC 666 Possible fore peak arrangements App Applied loads in fore peak area The following design loads have been considered: 1. External pressure on exposed deck (4/5.2) 2. Tank testing pressure (4/6.4) 3. Hydrostatic and hydrodynamic pressures (4/5.1) They are not relevant for deck structure. 4. Inertial pressure of fore peak tank (4/6.2). Inertial pressure on fore peak tank top is small compared to tank testing pressure and hence neglected. 5. Bow flare area pressure (4/5.4) This is not relevant for deck structure. 6. Lateral pressure in flooded condition (4/6.3) Technical Background of Rule Change Notice 1 July 2010 edition 35 / 63

84 Flooded condition may be relevant for a deck facing dry compartments. This is not applicable to fore peak tank top. 7. Design load in stores Design load in store space is not specified except for superstructure and deck house (9/4.3). A design load of 5 kn/m2 for unexposed decks is insignificant and hence neglected. App Scantlings calculation For sake of simplicity, effect of longitudinal side girders forming deck grillage is ignored except for C.L. girder thereby simple rule formulae can be applied. External pressure acting on the forecastle deck is transmitted to the fore peak tank top by a set of pillars. For sake of simplicity, the external pressure load supported by the pillars is re-distributed over the deck transverse on the fore peak tank top. In case of the Capesize bulk carrier, strength of the deck structure had to be checked by a direct calculation due to complexity of actual construction. For a complex deck structure, a direct strength calculation, typically beam model type, is considered necessary. App Comparison of scantlings Actual scantlings of deck transverse are compared against required scantlings according to the current rules and the new rules respectively. App Comparison of net section modulus Table 12 KC 666 Fore peak, net section modulus with the current rules Ship size Actual net section modulus (cm3) (A) Required net section modulus (cm3) Intact condition Test condition (B) (C) Ratio (A) / (B) Ratio (A) / (C) Handymax 2,663 1,781 NA 1.50 NA Panamax 7,077 3,919 NA 1.81 NA Capesize 15,439 11,129 NA 1.39 NA Table 13 KC 666 Fore peak, net section modulus with the proposed change Ship size Actual net section modulus (cm3) (A) Required net section modulus (cm3) Intact condition Test condition (B) (C) Ratio (A) / (B) Ratio (A) / (C) Handymax 2,663 1, Panamax 7,077 3,483 4, Capesize 15,439 9,892 17, *1 *1 According to a beam model calculation including deck structures above and connecting pillars, maximum normal stress of 0.76 R Y and maximum shear stress of 0.49 R Y are obtained which are acceptable according to the new rules. 36 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

85 App Comparison of net shear area Table 14 KC 666 Fore peak, net shear area with the current rules Ship size Actual net shear area (cm2) (A) Required net shear area (cm2) Intact condition (B) Test condition (C) Ratio (A) / (B) Ratio (A) / (C) Handymax NA 2.11 NA Panamax NA 1.75 NA Capesize NA 1.49 NA Table 15 KC 666 Fore peak, net shear area with the proposed change Ship size Actual net shear area (cm2) (A) Required net shear area (cm2) Intact condition (B) Test condition (C) Ratio (A) / (B) Ratio (A) / (C) Handymax Panamax Capesize *1 *1 According to a beam model calculation including deck structures above and connecting pillars, maximum normal stress of 0.76 R Y and maximum shear stress of 0.49 R Y are obtained which are acceptable according to the new rules. App Comments from the comparative study The following comments are made from the comparative study: 1. Actual scantlings of deck PSM in fore peak area are much above the requirements of the current rules. This is a common observation with the three example ships. 2. According to the new rules, required section modulus will be further reduced from the current requirements by 11% which may give rise to a significant reduction in actual scantlings if the structures are fully optimised according to the new rules. 3. In case of fore peak with void space (type B arrangement), tank testing condition may be decisive for deck PSM on fore peak tank top. This condition is missing in the current rules and therefore comparison is not possible. 4. Increase of allowable shear stress by 44% has no impact on actual scantlings. In all three example ships, required minimum web thickness (9/1[4.4.1]) will satisfy the web shear area requirement. 5. In case of the Capesize bulk carrier with a complex deck structure, a beam model calculation is performed to confirm that the actual scantlings comply with the rules. 6. In case of the Handymax bulk carrier, the face plate thickness of the deck PSM is thinner than the web plate thickness. It is observed that there is no proportional requirement for PSM in general and that the current minimum thickness requirement of Ch.9 Sec.1 [4.4.1] applies only to web plate of PSM. Technical Background of Rule Change Notice 1 July 2010 edition 37 / 63

86 App.1.3. Aft peak area App Target deck structure in aft peak area The same three ships as fore peak area (see Table 9) are used for the study of aft peak area. A typical deck transverse on upper deck is selected as illustrated in Figure 6. Target SG room Upp deck Pillars APT Figure 6 KC 666 used aft peak arrangements App Applied loads in aft peak area The following design loads have been considered: 1. External pressure on exposed deck (4/5.2) 2. Hydrostatic and hydrodynamic pressures (4/5.1) This is not relevant for deck structure. 3. Lateral pressure in flooded condition (4/6.3) This is not applicable to upper deck where flooded water head is zero. App Scantlings calculation For sake of simplicity, effect of longitudinal side girders forming deck grillage is ignored except for C.L. girder thereby simple rule formulae can be applied. App Comparison of scantlings Actual scantlings of deck transverse are compared against required scantlings according to the current rules and the new rules respectively. 38 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

87 App Comparison of net section modulus Table 16 KC 666 Aft peak, net section modulus with the current rules Ship size Actual net section modulus (cm3) (A) Required net section modulus (cm3) Intact condition (B) Test condition Ratio (A) / (B) Ratio (A) / (C) Handymax 1, NA 1.61 NA Panamax 2, NA 3.03 NA Capesize 3,325 2,452 NA 1.36 NA (C) Table 17 KC 666 Aft peak, net section modulus with the proposed change Ship size Actual net section modulus (cm3) (A) Required net section modulus (cm3) Intact condition (B) Test condition Ratio (A) / (B) Ratio (A) / (C) Handymax 1, NA 1.81 NA Panamax 2, NA 3.40 NA Capesize 3,325 2,179 NA 1.53 NA (C) App Comparison of net shear area Table 18 KC 666 Aft peak, net shear area with the current rules Ship size Actual net shear area (cm2) (A) Required net shear area (cm2) Intact condition (B) Test condition Ratio (A) / (B) Ratio (A) / (C) Handymax NA 2.33 NA Panamax NA 2.64 NA Capesize NA 2.04 NA (C) Table 19 KC 666 Aft peak, net shear area with the proposed change Ship size Actual net shear area (cm2) (A) Required net shear area (cm2) Intact condition (B) Test condition Ratio (A) / (B) Ratio (A) / (C) Handymax NA 3.37 NA Panamax NA 3.82 NA Capesize NA 2.94 NA (C) Technical Background of Rule Change Notice 1 July 2010 edition 39 / 63

88 App Comments from the comparative study The following comments are made from the comparative study: 1) Actual scantlings of deck PSM in aft peak area are much above the requirements of the current rules. This is a common observation with the three example ships. 2) According to the new rules, required section modulus will be further reduced from the current requirements by 11% which may give rise to a significant reduction in actual scantlings if the structures are fully optimised according to the new rules. 3) Increase of allowable shear stress by 44% has no impact on actual scantlings. In all three example ships, web shear area requirement will be satisfied if suitable web thickness is maintained for PSM which should be included in the rules same as fore peak area. App.1.4. Conclusion The following conclusion may be drawn from this consequence study. 1. Actual scantlings of deck PSM in fore and aft peak areas are much above the requirements. This is a common observation with the three example ships. Increase of hull steel weight is therefore not likely with this rule change. 2. According to the new rules, required section modulus will be further reduced from the current requirement by 11% which may give rise to a significant reduction in actual scantlings if the structures are fully optimised according to the new rules. 3. In case of fore peak with a large void space above fore peak tank, tank testing condition may be decisive for deck PSM on fore peak tank top. 4. Increase of allowable shear stress by 44% from the current rules has no impact on actual scantlings provided minimum web thickness (9/1[4.4.1]) is required for PSM. 5. For a complex deck structure, direct calculation should be acceptable instead of the simple rule formulae. 40 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

89 Appendix 2. KC 328 related documents Table 20 KC net thickness of web stiffeners and brackets on double bottom floor Figure 7 KC Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on double bottom floor Technical Background of Rule Change Notice 1 July 2010 edition 41 / 63

90 Table 21 KC 238 net thickness of web stiffeners and brackets on double bottom girder Figure 8 KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on double bottom girder 42 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

91 Table 22 KC 328 net thickness of web stiffeners and brackets on PSM in bilge hopper tanks Figure 9- KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on PSM in bilge hopper tanks Technical Background of Rule Change Notice 1 July 2010 edition 43 / 63

92 Table 23 KC 328 net thickness of web stiffeners and brackets on PSM in topside tanks Figure 10 KC 328 Comparison for net offered thickness of PSM web stiffener/bracket and net minimum required thickness in CSR-BC and the proposed Rule Change on PSM in topside tanks 44 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

93 Appendix 3. KC 798 Related documents The following documents are the different versions of the SOLAS regulations affecting the bulkead arrangement and reflected therefore in the CSR BC. The relevant parts of these texts for KC 798 are highlighted. Technical Background of Rule Change Notice 1 July 2010 edition 45 / 63

94 App.3.1. SOLAS Chapter II-1 Part B Regulation 10 The initial SOLAS regulation about subdivision arrangement which has served in fact as a basis for the CSR Chapter 2 Section 1 [3.1.1] is as follow. Chapter II-1 - Construction - Structure, subdivision and stability, machinery and electrical installations Part B - Subdivision and stability Regulation 10 - Peak and machinery space bulkheads, shaft tunnels, etc., in passenger ships 1. A forepeak or collision bulkhead shall be fitted which shall be watertight up to the bulkhead deck. This bulkhead shall be located at a distance from the forward perpendicular of not less than 5% of the length of the ship and not more than 3 m plus 5% of the length of the ship. 2. Where any part of the ship below the waterline extends forward of the forward perpendicular, e.g. a bulbous bow, the distances stipulated in paragraph 1 shall be measured from a point either:.1. at the mid-length of such extension; or.2. at a distance 1.5% of the length of the ship forward of the forward perpendicular; or.3. at a distance 3 m forward of the forward perpendicular; whichever gives the smallest measurement. 3. Where a long forward superstructure is fitted, the forepeak or collision bulkhead on all passenger ships shall be extended weathertight to the next full deck above the bulkhead deck. The extension shall be so arranged as to preclude the possibility of the bow door causing damage to it in the case of damage to, or detachment of, a bow door. 4. The extension required in paragraph 3 need not be fitted directly above the bulkhead below, provided that all parts of the extension are not located forward of the forward limit specified in paragraph 1 or paragraph 2. However, in ships constructed before 1 July 1997:.1. where a sloping ramp forms part of the extension, the part of the extension, which is more than 2.3 m above the bulkhead deck, may extend no more than 1 m forward of the forward limits specified in paragraph 1 or paragraph 2; and.2. where the existing ramp does not comply with the requirements for acceptance as an extension to the collision bulkhead and the position of the ramp prevents the siting of such extension within the limits specified in paragraph 1 or paragraph 2, the extension may be sited within a limited distance aft of the aft limit specified in paragraph 1 or paragraph 2. The limited distance aft should be no more than is necessary to ensure non interference with the ramp. The extension to the collision bulkhead shall open forward and comply with the requirements of paragraph 3 and shall be so arranged as to preclude the possibility of the ramp causing damage to it in the case of damage to, or detachment of, the ramp. 5. Ramps not meeting the above requirements shall be disregarded as an extension of the collision bulkhead. 6. In ships constructed before 1 July 1997, the requirements of paragraphs 3 and 4 shall apply not later than the date of the first periodical survey after 1 July An afterpeak bulkhead, and bulkheads dividing the machinery space, as defined in regulation 2, from the cargo and passenger spaces forward and aft, shall also be fitted and made watertight up to the bulkhead deck. The afterpeak bulkhead may, however, be stepped below the bulkhead deck, provided the degree of safety of the ship as regards subdivision is not thereby diminished. 8. In all cases stern tubes shall be enclosed in watertight spaces of moderate volume. The stern gland shall be situated in a watertight shaft tunnel or other watertight space separate from the stern tube compartment and of such volume that, if flooded by leakage through the stern gland, the margin line will not be submerged. 46 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

95 App.3.2. SOLAS Chapter II-1 Part B Regulation 11 The initial SOLAS regulation about subdivision arrangement which should have served as a basis for the CSR Chapter 2 Section 1 [3.1.1] is as follow. Chapter II-1 - Construction - Structure, subdivision and stability, machinery and electrical installations Part B - Subdivision and stability Regulation 11 - Peak and machinery space bulkheads and stern tubes in cargo ships. (Paragraphs 8 and 9 of this regulation apply to ships constructed on or after 1 February 1992) 1. For the purpose of this regulation freeboard deck, length of ship and forward perpendicular have the meanings as defined in the International Convention on Load Lines in force. 2. A collision bulkhead shall be fitted which shall be watertight up to the freeboard deck. This bulkhead shall be located at a distance from the forward perpendicular of not less than 5 % of the length of the ship or 10 m, whichever is the less, and, except as may be permitted by the Administration, not more than 8% of the length of the ship. 3. Where any part of the ship below the waterline extends forward of the forward perpendicular, e.g. a bulbous bow, the distances stipulated in paragraph 2 shall be measured from a point either:.1. at the mid-length of such extension; or.2. at a distance 1.5% of the length of the ship forward of the forward perpendicular; or.3. at a distance 3 m forward of the forward perpendicular; whichever gives the smallest measurement. 4. The bulkhead may have steps or recesses provided they are within the limits prescribed in paragraph 2 or 3. Pipes piercing the collision bulkhead shall be fitted with suitable valves operable from above the freeboard deck and the valve chest shall be secured at the bulkhead inside the forepeak. The valves may be fitted on the after side of the collision bulkhead provided that the valves are readily accessible under all service conditions and the space in which they are located is not a cargo space. All valves shall be of steel, bronze or other approved ductile material. Valves of ordinary cast iron or similar material are not acceptable. No door, manhole, ventilation duct or any other opening shall be fitted in this bulkhead. 5. Where a long forward superstructure is fitted the collision bulkhead shall be extended weathertight to the deck next above the freeboard deck. The extension need not be fitted directly above the bulkhead below provided it is located within the limits prescribed in paragraph 2 or 3 with the exemption permitted by paragraph 6 and the part of the deck which forms the step is made effectively weathertight. 6. Where bow doors are fitted and a sloping loading ramp forms part of the extension of the collision bulkhead above the freeboard deck the part of the ramp which is more than 2.3 m above the freeboard deck may extend forward of the limit specified in paragraph 2 or 3. The ramp shall be weathertight over its complete length. 7. The number of openings in the extension of the collision bulkhead above the freeboard deck shall be restricted to the minimum compatible with the design and normal operation of the ship. All such openings shall be capable of being closed weathertight. 8. Bulkheads shall be fitted separating the machinery space from cargo and passenger spaces forward and aft and made watertight up to the freeboard deck. 9. Stern tubes shall be enclosed in a watertight space (or spaces) of moderate volume. Other measures to minimize the danger of water penetrating into the ship in case of damage to stern tube arrangements may be taken at the discretion of the Administration. Technical Background of Rule Change Notice 1 July 2010 edition 47 / 63

96 App.3.3. SOLAS Chapter II-1 Part B-2 Regulation 12 The current SOLAS regulation about subdivision arrangement which is to be considered from now on in the CSR Chapter 2 Section 1 [3.1.1] is as follow. Chapter II-1 - Construction - Structure, subdivision and stability, machinery and electrical installations Part B-2 - Subdivision, Watertight and Weathertight Integrity Regulation 12 - Peak and machinery space bulkheads, shaft tunnels, etc. 1. A collision bulkhead shall be fitted which shall be watertight up to the bulkhead deck. This bulkhead shall be located at a distance from the forward perpendicular of not less than 0.05L or 10 m, whichever is the less, and, except as may be permitted by the Administration, not more than 0.08L or 0.05L + 3 m, whichever is the greater. 2. Where any part of the ship below the waterline extends forward of the forward perpendicular, e.g., a bulbous bow, the distances stipulated in paragraph 1 shall be measured from a point either:.1. at the mid-length of such extension;.2. at a distance 0.015L forward of the forward perpendicular; or.3. at a distance 3 m forward of the forward perpendicular, whichhever gives the smallest measurement. 3. The bulkhead may have steps or recesses provided they are within the limits prescribed in paragraph 1 or No doors, manholes, access openings, ventilation ducts or any other openings shall be fitted in the collision bulkhead below the bulkhead deck Except as provided in paragraph 5.2, the collision bulkhead may be pierced below the bulkhead deck by not more than one pipe for dealing with fluid in the forepeak tank, provided that the pipe is fitted with a screwdown valve capable of being operated from above the bulkhead deck, the valve chest being secured inside the forepeak to the collision bulkhead. The Administration may, however, authorize the fitting of this valve on the after side of the collision bulkhead provided that the valve is readily accessible under all service conditions and the space in which it is located is not a cargo space. All valves shall be of steel, bronze or other approved ductile material. Valves of ordinary cast iron or similar material are not acceptable If the forepeak is divided to hold two different kinds of liquids the Administration may allow the collision bulkhead to be pierced below the bulkhead deck by two pipes, each of which is fitted as required by paragraph 5.1, provided the Administration is satisfied that there is no practical alternative to the fitting of such a second pipe and that, having regard to the additional subdivision provided in the forepeak, the safety of the ship is maintained. 6. Where a long forward superstructure is fitted the collision bulkhead shall be extended weathertight to the deck next above the bulkhead deck. The extension need not be fitted directly above the bulkhead below provided it is located within the limits prescribed in paragraph 1 or 2 with the exception permitted by paragraph 7 and that the part of the deck which forms the step is made effectively weathertight. The extension shall be so arranged as to preclude the possibility of the bow door causing damage to it in the case of damage to, or detachment of, a bow door. 7. Where bow doors are fitted and a sloping loading ramp forms part of the extension of the collision bulkhead above the bulkhead deck the ramp shall be weathertight over its complete length. In cargo ships the part of the ramp which is more than 2.3 m above the bulkhead deck may extend forward of the limit specified in paragraph 1 or 2. Ramps not meeting the above requirements shall be disregarded as an extension of the collision bulkhead. 8. The number of openings in the extension of the collision bulkhead above the freeboard deck shall be restricted to the minimum compatible with the design and normal operation of the ship. All such openings shall be capable of being closed weathertight. 9. Bulkheads shall be fitted separating the machinery space from cargo and accommodation spaces forward and aft and made watertight up to the bulkhead deck. In passenger ships an afterpeak bulkhead shall also be fitted and made watertight up to the bulkhead deck. The afterpeak bulkhead may, however, be stepped below the bulkhead deck, provided the degree of safety of the ship as regards subdivision is not thereby diminished. 10. In all cases stern tubes shall be enclosed in watertight spaces of moderate volume. In passenger ships the stern gland shall be situated in a watertight shaft tunnel or other watertight space separate from the stern tube compartment and of such volume that, if flooded by leakage through the stern gland, the bulkhead deck will not be immersed. In cargo ships other measures to minimize the danger of water penetrating into the ship in case of damage to stern tube arrangements may be taken at the discretion of the Administration. 48 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

97 Appendix 4. KC 966 related document The following attachment is the IACS guideline as provided in KC 966 in the knowledge centre database. The relevant parts of these texts for KC 966 are highlighted. Technical Background of Rule Change Notice 1 July 2010 edition 49 / 63

98 App.4.1. IACS Guideline for Procedures of Testing Tanks and Tight Boundaries 1. General IACS Guideline for Procedures of Testing Tanks and Tight Boundaries These test procedures are to ensure the weathertightness of structures/shipboard outfitting, the watertightness of tanks and watertight boundaries and structural adequacy of tanks. Tightness of all tanks and tight boundaries of the ships at the new construction and, when major conversions or repairs * have been made, those relevant to the major conversions/repairs should be confirmed by these test procedures prior to delivery of the ship. * Major repair means a repair affecting structural integrity. 2. Application 2.1 All gravity tanks ** and other boundaries required to be watertight or weathertight should be tested in accordance with this Guideline and proven tight and structurally adequate as follows: Gravity Tanks for their tightness and structural adequacy Watertight Boundaries Other Than Tank Boundaries for their watertightness, and - Weathertight Boundaries for their weathertightness ** Gravity tank means a tank having a design working pressure not greater than 70 kpa at the top of the tank. 2.2 The testing of cargo containment systems of liquefied gas carriers should be in accordance with standards deemed appropriate by the Administration. 2.3 Testing of structures not listed in Table 1 or 2 should be specially considered. 3. Types of Tests and Definition of Test 3.1 The following two types of test are specified in this requirement: Structural Test: A test to verify the structural adequacy of the construction of the tanks. This may be a hydrostatic test or, where the situation warrants, a hydropneumatic test. Leak Test: A test to verify the tightness of the boundary. Unless a specific test is indicated, this may be a hydrostatic/hydropneumatic test or air test. Leak test with remark *3 in Table 1 includes hose test as an acceptable medium of the test. 3.2 Definition of each type of test is as follows: Hydrostatic Test: (Leak and Structural) Hydropneumatic Test: (Leak and Structural) Hose Test: (Leak) Air Tests: (Leak) A test by filling the space with a liquid to specified head. A test wherein space is partially filled with liquid and air pressure applied on top of the liquid surface. A test to verify the tightness of the joint by a jet of water. A test to verify the tightness by means of air pressure differential and leak detection solution. It includes tank air test and joint air test, such as compressed air test and vacuum box test. 50 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

99 Compressed Air Fillet Weld Test: (Leak) Vacuum Box Test: (Leak) Ultrasonic Test: (Leak) Penetration Test: (Leak) An air test of fillet welded tee joint and leak indicating solution applied on the fillet welds. A box over a joint with leak indicating solution appliedon the fillet or butt welds. Vacuum is created inside the box to detect any leaks. A test to verify the tightness of a sealing by means of ultrasonic. A test to verify that no continuous leakages exist in the boundaries of a compartment by means of low surface tension liquids. 4. Test Procedures 4.1 General Tests should be carried out in the presence of the Surveyor at a stage sufficiently close to the completion of the work with all hatches, doors, windows, etc. installed and all penetrations including pipe connections fitted, and before any ceiling and cement work is applied over the joints. Specific test requirements are given in 4.4 and Table 1. For the timing of application of coating and provision of safe access to joints, see 4.5, 4.6 and Table Structural Test Procedures Type and Time of Test Where a structural test is specified in Table 1 or Table 2, a hydrostatic test in accordance with will be acceptable. Where practical limitations (strength of building berth, light density of liquid, etc.) prevent the performance of a hydrostatic test, a hydropneumatic test in accordance with may be accepted as an equivalent method. Provided the results of a leak test are confirmed satisfactory, a hydrostatic test for confirmation of structural adequacy may be carried out while the vessel is afloat Number of Structural Test (1) Structural test should be carried out for at least one tank of same construction (i.e., same design and same workmanship) on each vessel provided all subsequent tanks are tested for leaks by an air test. However, where structural adequacy of a tank was verified by structural testing required in Table 1, the subsequent vessels in the series (i.e., sister ships built in the same shipyard) may be exempted from such testing for other tanks which have the structural similarity to the tested tank, provided that the water-tightness in all boundaries of exempted tanks are verified by leak tests and thorough inspection should be carried out. For sister ships built several years after the last ship of the series, such exemption may be reconsidered. In any case, structural testing should be carried out for at least one tank for each vessel in order to assure structural fabrication adequacy. (2) For watertight boundaries of spaces other than tanks (excluding chain lockers), structural testing may be exempted, provided that the water-tightness in all boundaries of exempted spaces are verified by leak tests and thorough inspection should be carried out. (3) These subsequent tanks may require structural test if found necessary after the structural testing of the first tank. (4) Tanks for structural test should be selected so that all representative structural members are tested for the expected tension and compression. Technical Background of Rule Change Notice 1 July 2010 edition 51 / 63

100 4.3 Leak Test Procedures For leak test specified in Table 1, tank air test, compressed air fillet weld test, vacuum box test in accordance with through 4.4.6, or their combination will be acceptable. Hydrostatic or hydropneumatic test may also be accepted as leak test provided 4.5 and 4.6 are complied with. Hose test will also be acceptable for the locations as specified in Table 1 with the foot note *3. Joint air test may be carried out in the block stage provided all work of the block that may affect the tightness of the joint is completed before the test. See also for the application of final coating and 4.6 for safe access to joint and their summary in Table Details of Tests Hydrostatic Test Unless other liquid is approved, hydrostatic test is to consist of filling the space by fresh water or sea water, whichever is appropriate for testing of the space, to the level specified in Table 1 or Table 2. In case a tank for cargoes with higher density is to be tested with fresh water or sea water, the testing pressure height should be specially considered Hydropneumatic Test Hydropneumatic test where approved should be such that the test condition in conjunction with the approved liquid level and air pressure will simulate the actual loading as far as practicable. The requirements and recommendations for tank air tests in will also apply to hydropneumatic test Hose Test Hose test should be carried out with the pressure in the hose nozzle maintained at least at Pa during the test. The nozzle should have a minimum inside diameter of 12 mm and be at a distance to the joint not exceeding 1.5meters. Where hose test is not practical because of possible damage to machinery, electrical equipment insulation or outfitting items, it may be replaced by a careful visual examination of welded connections, supported where necessary by means such as a dye penetrant test or ultrasonic leak test or an equivalent Tank Air Test All boundary welds, erection joints and penetrations including pipe connections should be examined in accordance with the approved procedure and under a pressure differential above atmosphere pressure not less than Pa with a leak indication solution applied. It is recommended that the air pressure in the tank be raised to and maintained at about Pa for approximately one hour, with a minimum number of personnel around the tank, before lowered to the test pressure of Pa. A U-tube with a height sufficient to hold a head of water corresponding to the required test pressure should be arranged. The cross sectional area of the U-tube should be not less than that of the pipe supplying air to the tank. In addition to U-tube, a master gauge or other approved means to verify the pressure should be approved Compressed Air Fillet Weld Test In this air test, compressed air is injected from one end of fillet welded joint and the pressure verified at the other end of joint by a pressure gauge on the opposite side. Pressure gauges should be arranged so that an air pressure of at least Pa can be verified at each end of all passages within the portion being tested. Note: Where the leak test is required in way of the fabrication applying the partial penetration weld, compressed air test is also applied in the same manner for fillet weld where the root face is sufficiently large, i.e., 6 8 mm. 52 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

101 4.4.6 Vacuum Box Test A box (vacuum tester) with air connections, gauges and inspection window is placed over the joint with leak indicator applied. The air within the box is removed by an ejector to create a vacuum of Pa inside the box Ultrasonic Test An arrangement of an ultrasonic echoes sender inside of a compartment and a receiver outside. A location where the sound is detectable by the receiver displays a leakage in the sealing of the compartment Penetration Test A test of butt welds by using of a low surface tension liquid at one side of a compartment boundary. If no liquid were detected on the opposite sides of the boundaries after expiration of a definite time this means the verification of tightness of the compartments boundaries Other Test Other methods of testing may be considered by each society upon submission of full particulars prior to commencement of the testing. 4.5 Application of Coating Final Coating For butt joints by automatic process, final coating may be applied anytime before completion of leak test of the space bounded by the joint. For all other joints, final coating should be applied after the completion of leak test of the joint. See also Table 3. The Surveyor reserves a right to require leak test prior to the application of final coating over automatic erection butt welds Temporary Coating Any temporary coating which may conceal defects or leaks should be applied at a time as specified for final coating. This requirement does not apply to shop primer. 4.6 Safe Access to Joints For leak tests, a safe access to all joints under examination should be provided. See also Table 3. Tank or boundaryto be tested Table 1 Test Requirements for Tanks and Boundaries Test type Test head or pressure Remarks 1 Double bottom tanks *4 Leak &Structural *1 The greater of - top of the overflow, - to 2.4m above top of tank *2, or - to bulkhead deck 2 Double bottom voids *5 Leak See through 4.4.6, as applicable 3 Double side tanks Leak & Structural *1 The greater of - top of the overflow, Technical Background of Rule Change Notice 1 July 2010 edition 53 / 63

102 Tank or boundaryto be tested Test type Test head or pressure Remarks - to 2.4m above top of tank *2, or - to bulkhead deck 4 Double side voids Leak See through 4.4.6, as Applicable 5 Deep tanks other than those listed elsewhere in this table Leak & Structural *1 The greater of - top of the overflow, or - to 2.4m above top of tank *2 6 Cargo oil tanks Leak & Structural *1 The greater of - top of the overflow, - to 2.4m above top of tank *2, or - to top of tank *2 plus setting of any pressure relief valve 7 Ballast hold of bulk carriers Leak & Structural *1 The greater of - top of the overflow, or - top of cargo hatch coaming 8 Peak tanks Leak & Structural *1 The greater of - top of the overflow, or - to 2.4m above top of tank *2 9 a. Fore peak voids Leak See through 4.4.6, as applicable b. Aft peak voids Leak See through 4.4.6, as applicable 10 Cofferdams Leak See through 4.6, as applicable 11 a. Watertight bulkheads Leak See through 4.4.6, as applicable b. Superstructure end bulkhead 12 Watertight doors below freeboard or bulkhead deck Leak Leak *6 See through 4.4.6, as applicable See through 4.4.6, as applicable 13 Double plate rudder blade Leak See through 4.4.6, as applicable 14 Shaft tunnel clear of deep tanks Leak *3 See through 4.4.6, as applicable 15 Shell doors Leak *3 See through 4.4.6, as applicable 16 Weathertight hatch covers and closing appliances 17 Dual purpose tank/dry cargo hatch cover Leak *3 Leak *3 See through 4.4.6, as applicable See through 4.4.6, as applicable 18 Chain locker Leak & Structural Top of chain pipe 19 Independent tanks Leak & Structural*1 The greater of - top of the overflow, or - to 0.9m above top of tank 20 Ballast ducts Leak & Structural*1 The greater of - ballast pump maximum pressure, or - setting of any pressure relief valve After peak to be tested after installation of stern tube After peak to be tested after installation of stern tube Hatch covers closed by tarpaulins and battens excluded In addition to structural test in item 6 or 7 54 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

103 Note: *1 Structural test is to be carried out for at least one tank of same construction (i.e., same design and same workmanship) on each vessel provided all subsequent tanks are tested for leaks by an air test. However, where structural adequacy of a tank was verified by structural testing, the subsequent vessels in the series (i.e., sister ships built in the same shipyard) may be exempted from such testing for other tanks which have the structural similarity to the tested tank, provided that the water-tightness in all boundaries of exempted tanks are verified by leak tests and thorough inspection are to be carried out. In any case, structural testing is to be carried out for at least one tank for each vessel in order to assure structural fabrication adequacy. (See 4.2.2(1)) *2 Top of tank is deck forming the top of the tank excluding any hatchways. *3 Hose Test may also be considered as a medium of the test. See 3.2. *4 Including tanks arranged in accordance with the provisions of SOLAS regulation II-1/9.4 *5 Including duct keels and dry compartments arranged in accordance with the provisions of SOLAS regulation II-1/9.4 *6 Where water tightness of watertight door has not confirmed by prototype test, testing by filling watertight spaces with water is to be carried out. See SOLAS regulation II-1/16.2 and MSC/Circ Type of Ship/Tank 1 Liquefied gas carrier 2 Edible liquid tanks 3 Chemical carrier Table 2 Additional Test Requirements for Special Service Ships/Tanks Structures to be tested Cargo containment systems (See remarks) Independent tanks Integral or independent cargo tanks Type of Test Test Head or Pressure Remarks See See See also Table 1 for other tanks and boundaries Leak & Structural Leak & Structural The greater of - top of the overflow, or - to 0.9m above top of tank *1 The greater of - to 2.4m above top of tank *1, or - to top of tank *1 plus setting of any pressure relief valve Note: *1 Top of tank is deck forming the top of the tank excluding any hatchways. Table 3 Application of Leak Test, Coating and Provision of Safe Access For Type of Welded Joints Type of Welded Joints Leak Test Coating *1 Safe Access *2 Before Leak Test Leak Test Structural Test After Leak Test & before Structural Test Butt Automatic Not required Allowed N/A Not required Not required Fillet Note: Manual or Semi-automatic Boundary including penetrations Required Not allowed Allowed Required Not required Required Not allowed Allowed Required Not required Technical Background of Rule Change Notice 1 July 2010 edition 55 / 63

104 *1 Coating refers to internal (tank/hold coating), where applied, and external (shell/deck) painting. It does not refer to shop primer. *2 Temporary means of access for verification of the leak test 56 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

105 Appendix 5. KC 1009 related documents The following documents are IMO and IACS definitions and recommendations regarding the definitions of bulk carriers. The relevant parts of these texts for KC 1009 are highlighted. App.5.1. SOLAS Chapter IX Regulation 1 The first definition of a bulk carrier is given in the following SOLAS regulation. SOLAS - International Convention for the Safety of Life at Sea Chapter IX - Management for the safe operation of ships Regulation 1 - Definitions. For the purpose of this chapter, unless expressly provided otherwise: 1. International Safety Management (ISM) Code means the International Management Code for the Safe Operation of Ships and for Pollution Prevention adopted by the Organization by resolution A.741(18), as may be amended by the Organization, provided that such amendments are adopted, brought into force and take effect in accordance with the provisions of article VIII of the present Convention concerning the amendment procedures applicable to the annex other than chapter I. 2. Company means the owner of the ship or any other organization or person such as the manager, or the bareboat charterer, who has assumed the responsibility for operation of the ship from the owner of the ship and who on assuming such responsibility has agreed to take over all the duties and responsibilities imposed by the International Safety Management Code. 3. Oil tanker means an oil tanker as defined in regulation II-1/ Chemical tanker means a chemical tanker as defined in regulation VII/ Gas carrier means a gas carrier as defined in regulation VII/ Bulk carrier means a ship which is constructed generally with single deck, top-side tanks and hopper side tanks in cargo spaces, and is intended primarily to carry dry cargo in bulk, and includes such types as ore carriers and combination carriers. ( Refer to resolution MSC.79(70) relating to interpretation of provisions of SOLAS chapter XII on additional safety measures for bulk carriers.) 7. Mobile offshore drilling unit (MODU) means a vessel capable of engaging in drilling operations for the exploration for or exploitation of resources beneath the sea-bed such as liquid or gaseous hydrocarbons, sulphur or salt. 8. High-speed craft means a craft as defined in regulation X/1. App.5.2. SOLAS Chapter XII Regulation 1 The second definition of a bulk carrier is given in the following SOLAS regulation SOLAS - International Convention for the Safety of Life at Sea Chapter XII - Additional safety measures for bulk carriers Regulation 1 - Definitions. For the purpose of this chapter: 1. Bulk carrier means a ship which is intended primarily to carry dry cargo in bulk, including such types as ore carriers and combination carriers. Reference is made to: Technical Background of Rule Change Notice 1 July 2010 edition 57 / 63

106 For ships constructed before 1 July 2006, resolution 6, Interpretation of the definition of bulk carrier, as given in chapter IX of SOLAS 1974, as amended in 1994, adopted by the 1997 SOLAS Conference. The Interpretation of the provisions of SOLAS chapter XII on Additional safety measures for bulk carriers, adopted by the Maritime Safety Committee of the Organization by resolution MSC.79(70). The application provisions of Annex 1 to the Interpretation of the provisions of SOLAS chapter XII on Additional safety measures for bulk carriers, adopted by the Maritime Safety Committee of the Organization by resolution MSC.89(71). 2. Bulk carrier of single-side skin construction means a bulk carrier as defined in paragraph 1, in which:.1. any part of a cargo hold is bounded by the side shell; or.2. where one or more cargo holds are bounded by a double-side skin, the width of which is less than 760 mm in bulk carriers constructed before 1 January 2000 and less than 1,000 mm in bulk carriers constructed on or after 1 January 2000 but before 1 July 2006, the distance being measured perpendicular to the side shell. Such ships include combination carriers in which any part of a cargo hold is bounded by the side shell. 3. Bulk carrier of double-side skin construction means a bulk carrier as defined in paragraph 1, in which all cargo holds are bounded by a double-side skin, other than as defined in paragraph Double-side skin means a configuration where each ship side is constructed by the side shell and a longitudinal bulkhead connecting the double bottom and the deck. Hopper side tanks and top-side tanks may, where fitted, be integral parts of the double-side skin configuration. 5. Length of a bulk carrier means the length as defined in the International Convention on Load Lines in force. 6. Solid bulk cargo means any material, other than liquid or gas, consisting of a combination of particles, granules or any larger pieces of material, generally uniform in composition, which is loaded directly into the cargo spaces of a ship without any intermediate form of containment. 7. Bulk carrier bulkhead and double bottom strength standards means "Standards for the evaluation of scantlings of the transverse watertight vertically corrugated bulkhead between the two foremost cargo holds and for the evaluation of allowable hold loading of the foremost cargo hold" adopted by resolution 4 of the Conference of Contracting Governments to the International Convention for the Safety of Life at Sea, 1974 on 27 November 1997, as may be amended by the Organization, provided that such amendments are adopted, brought into force and take effect in accordance with the provisions of article VIII of the present Convention concerning the amendment procedures applicable to the Annex other than chapter I. 8. Bulk carriers constructed means bulk carriers the keels of which are laid or which are at a similar stage of construction. 9. A similar stage of construction means the stage at which:.1. construction identifiable with a specific ship begins; and.2. assembly of that ship has commenced comprising at least 50 tonnes or one per cent of the estimated mass of all structural material, whichever is less. 10. Breadth (B) of a bulk carrier means the breadth as defined in the International Convention on Load Lines in force. App.5.3. Resolution MSC.79(70) Resolution MSC.79(70) Interpretation of the Provisions of SOLAS Chapter XII on Additional Safety Measures for Bulk Carriers - (adopted on 11 December 1998) The Maritime Safety Committee. RECALLING Article 28(b) of the Convention on the International Maritime Organization concerning the functions of the Committee,. NOTING that the 1997 SOLAS Conference adopted new chapter XII of the International Convention for the Safety of Life at Sea (SOLAS), 1974 concerning additional safety measures for bulk carriers,. NOTING FURTHER that SOLAS chapter XII is expected to enter into force on 1 July 1999,. DESIRING to ensure that all Contracting Governments to the 1974 SOLAS Convention implement SOLAS chapter XII in a consistent and uniform manner, 58 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

107 . RECOGNIZING, therefore, the need to establish, for that purpose, guidance on applications of, and the interpretation to, the relevant provisions of that chapter,. RESPONDING to the requests of the 1997 SOLAS Conference, as recorded in Conference resolutions 6 and 8 thereof, 1.. URGES Governments concerned to:.1. ensure that bulk carriers to which SOLAS chapter XII applies are clearly identified as such, either on the Safety Management Certificate issued under the provisions of SOLAS chapter IX, or in the booklet required under the provisions of SOLAS regulation XII/8;.2. further ensure that where the identification of "bulk carrier" on the Safety Management Certificate issued under the provisions of SOLAS chapter IX is in question, the interpretation of "bulk carrier" contained in resolution 6 of the 1997 SOLAS Conference be accepted for the issuance and verification of compliance with chapter IX;.3. ensure that ships to which SOLAS regulation XII/4.2 applies are not permitted to be subject to the provisions of SOLAS regulation XII/9 by means of modifications that would render non watertight one or more watertight transverse bulkheads; and.4. interpret the provisions of SOLAS regulation XII/10.2 as follows: For bulk carriers of 150 m in length and upwards of single side skin construction constructed before 1 July 1999, any cargo carried on or after the implementation date specified in regulation 3 and declared to have a density within the range of 1250 to 1780 kg/m 3 shall have its density verified by an accredited testing organization, unless such bulk carriers comply with all the relevant requirements of this chapter applicable to be carriage of solid bulk cargoes having a density of 1780 kg/m 3 and above."; and 2.. INVITES Governments concerned to bring the contents of this resolution to the attention of all parties concerned. App.5.4. SOLAS/CONF.4 Resolution 6 SOLAS/CONF.4 Resolutions of the Conference of Contracting Governments to the International Convention for the Safety of Life at Sea, (November 1997) Resolution 6 - Interpretation of the definition of bulk carrier, as given in chapter IX of SOLAS 1974, as amended in (Adopted on 27 November 1997) - The Conference, The Conference,. HAVING ADOPTED amendments to the International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, concerning the safety of bulk carriers.. NOTING that SOLAS chapter IX will enter into force on 1 July 1998,. NOTING ALSO that bulk carriers will have to comply with the requirements of SOLAS chapter IX by 1 July 1998,. NOTING FURTHER that the expected entry into force of the new SOLAS chapter XII on 1 July 1999 will make new requirements mandatory for bulk carriers,. RECOGNIZING that a number of SOLAS Contracting Governments have identified certain ambiguities in the definition of the term "bulk carrier", as given in SOLAS regulation IX/1.6, causing diverging interpretations of this term,. RECOGNIZING FURTHER the need to establish, for the purpose of the application of the new SOLAS chapter XII, guidance to Contracting Governments and to the industry as to which ships are subject to the new requirements,. BEING AWARE of the urgent need to establish, for the purpose of the application of SOLAS chapter IX on 1 July 1998, a clear guidance to Contracting Governments and to the industry as to which specific ships are subject to the requirements of the International Safety Management (ISM) Code,. DESIRING to ensure that all Contracting Governments should implement the ISM Code and the new SOLAS chapter XII in their capacity as flag State or as port State exercising control under the provisions of the Technical Background of Rule Change Notice 1 July 2010 edition 59 / 63

108 Convention, in a consistent, systematic and harmonized manner, with a view of facilitating international seaborne trade,. CONSCIOUS of the fact that SOLAS chapter IX should be applied taking into account Conference resolution 9, as soon as possible, 1.. URGES SOLAS Contracting Governments to interpret the definition of the term "bulk carrier", given in regulation IX/1.6, for the purpose of the application of SOLAS regulation IX/2.1.2 and chapter XII to mean: ships constructed with single deck, top-side tanks and hopper side tanks in cargo spaces and intended primarily to carry dry cargo in bulk; or ore carriers 1 ; or combination carriers 2 ; 2.. INVITES the Maritime Safety Committee of the International Maritime Organization to consider, as soon as possible: (a). actions necessary to remove the ambiguity which exists in the definition of the term "bulk carrier" as given in SOLAS regulation IX/1.6; and (b). any other appropriate action which will facilitate the easy identification of the type of ship by SOLAS Contracting Governments when exercising their rights of control under the provisions of that Convention. App.5.5. UR Z10.2- Rev. 27 (March 2009) The following excerpt gives the definitions of bulk carriers as per IACS UR Z Hull Surveys of Bulk Carriers: 1.2 Definitions Bulk Carrier A Bulk Carrier is a ship which is constructed generally with single deck, topside tanks and hopper side tanks in cargo spaces, and is intended primarily to carry dry cargo in bulk. Combination carriers are included Double Skin Bulk Carrier A Double Skin Bulk Carrier is a ship which is constructed generally with single deck, topside tanks and hopper side tanks in cargo spaces, and is intended primarily to carry dry cargo in bulk, including such types as ore carriers and combination carriers 4, in which all cargo holds are bounded by a double-side skin (regardless of the width of the wing space). 1 Ore carrier means a sea-going single-deck ship having two longitudinal bulkheads and a double bottom throughout the cargo region and intended for the carriage of ore cargoes in the centre holds only 2 Combination carrier has the same meaning as in SOLAS regulation II-2/ For single skin combination carriers additional requirements are specified in UR Z For combination carriers with longitudinal bulkheads additional requirements are specified in UR Z10.1 or UR Z10.4, as applicable. 60 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

109 App.5.6. UR Z10.5- Rev. 9 (March 2009) The following excerpt gives the definitions of bulk carriers as per IACS UR Z hull surveys of double skin bulk carriers: 1.2 Definitions Double Skin Bulk Carrier A Double Skin Bulk Carrier is a ship which is constructed generally with single deck, top-side tanks and hopper side tanks in cargo spaces, and is intended primarily to carry dry cargo in bulk, including such types as ore carriers and combination carriers1), in which all cargo holds are bounded by a double-side skin (regardless of the width of the wing space). Technical Background of Rule Change Notice 1 July 2010 edition 61 / 63

110 Appendix 6. KC 1082 related documents App.6.1. SOLAS Chapter IX Regulation 1 ANNEX 9 RESOLUTION MSC.223(82) (adopted on 8 December 2006) MSC 82/24/Add.1 ADOPTION OF AMENDMENTS TO THE PROTOCOL OF 1988 RELATING TOTHE INTERNATIONAL CONVENTION ON LOAD LINES, 1966, AS AMENDEDTHE MARITIME SAFETY COMMITTEE, RECALLING Article 28(b) of the Convention on the International Maritime Organization concerning the functions of the Committee, RECALLING FURTHER article VI of the Protocol of 1988 relating to the International Convention on Load Lines, 1966 (hereinafter referred to as the 1988 Load Lines Protocol ) concerning amendment procedures, HAVING CONSIDERED, at its eighty-second session, amendments to the 1988 Load Lines Protocol proposed and circulated in accordance with paragraph 2(a) of article VI thereof, 1. ADOPTS, in accordance with paragraph 2(d) of article VI of the 1988 Load Lines Protocol, amendments to the 1988 Load Lines Protocol, the text of which is set out in the Annex to the present resolution; 2. DETERMINES, in accordance with paragraph 2(f)(ii)(bb) of article VI of the 1988 Load Lines Protocol, that the said amendments shall be deemed to have been accepted on 1 January 2008, unless, prior to that date, more than one third of the Parties to the 1988 Load Lines Protocol or Parties the combined merchant fleets of which constitute not less than 50% of the gross tonnage of the world s merchant fleet, have notified their objections to the amendments; 3. INVITES the Parties concerned to note that, in accordance with paragraph 2(g)(ii) of article VI of the 1988 Load Lines Protocol, the amendments shall enter into force on 1 July 2008 upon their acceptance in accordance with paragraph 2 above; 4. REQUESTS the Secretary-General, in conformity with paragraph 2(e) of article VI of the 1988 Load Lines Protocol, to transmit certified copies of the present resolution and the text of the amendments contained in the Annex to all Parties to the 1988 Load Lines Protocol; 5. FURTHER REQUESTS the Secretary-General to transmit copies of this resolution and its Annex to Members of the Organization, which are not Parties to the 1988 Load Lines Protocol. I:\MSC\82\24-Add-1.doc 62 / 63 Technical Background of Rule Change Notice 1 July 2010 edition

111 MSC 82/24/Add.1 ANNEX 9 Page 2 ANNEX AMENDMENTS TO THE PROTOCOL OF 1988 RELATING TO THE INTERNATIONAL CONVENTION ON LOAD LINES, 1966, AS AMENDED ANNEX B ANNEXES TO THE CONVENTION AS MODIFIED BY THE PROTOCOL OF 1988 RELATING THERETO ANNEX I REGULATIONS FOR DETERMINING LOAD LINES CHAPTER II CONDITIONS OF ASSIGNMENT OF FREEBOARD Regulation 22 Scuppers, inlets and discharges 1 In paragraph (4) of the regulation, the reference to (2) is replaced by reference to (1). CHAPTER III FREEBOARDS Regulation 39 Minimum bow height and reserve buoyancy 2 In paragraph (1) of the regulation, the words dl is the draught at 85% of the depth D, in metres; are replaced by the words dl is the draught at 85% of the least moulded depth, in metres;. *** I:\MSC\82\24-Add-1.doc Technical Background of Rule Change Notice 1 July 2010 edition 63 / 63

112 Common Structural Rules for Double Hull Oil Tankers, July 2010 Rule Change Notice 1 (1 July 2010 consolidated edition) Notes: (1) These Rule Changes enter into force on 1 st July (2) The Rule amendments in this document are applicable to the Common Structural Rules for Double Hull Oil Tankers, July Copyright in these Common Structural Rules for Double Hull Oil Tankers is owned by: American Bureau of Shipping Bureau Veritas China Classification Society Det Norske Veritas Germanischer Lloyd Korean Register of Shipping Lloyd's Register Nippon Kaiji Kyokai Registro Italiano Navale Russian Maritime Register of Shipping Copyright 2006 The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as the IACS Members. The IACS Members, individually and collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant IACS Member entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

113 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 RULE CHANGE NOTICE 1 This notice contains amendments within the following Sections of the Common Structural Rules for Double Hull Oil Tankers, July The amendments are effective on the dates shown: Section Paragraph/Figure/Table Effective Date Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section 6 Table July 2012 Section July 2012 Section 6 Figure July 2012 Section July 2012 Section 7 Table July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section 8 Table July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section July 2012 Section 11 Table July 2012 Section 11 Figure July 2012 Section July 2012 Section July 2012 Section 11 Table July 2012 Appendix A Miscellaneous paragraphs 1 July 2012 Appendix B and July 2012 PAGE 2 OF 48

114 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section Paragraph/Figure/Table Effective Date Appendix B July 2012 Appendix B July 2012 Appendix B July 2012 Appendix C July 2012 This notice contains editorial amendments within the following Sections of the Common Structural Rules for Double Hull Oil Tankers, July Section Paragraph/Figure/Table Type Section 6 Figure Editorial PAGE 3 OF 48

115 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 For technical background for Rule Changes in this present document, reference is made to separate document Technical Background for Rule Change Notice 1. SECTION 4 - BASIC INFORMATION 2.6 Geometrical Properties of the Hull Girder Cross-Section Effective area for calculation of hull girder moment of inertia and section modulus When several openings are located in or adjacent to the same cross-section, the total equivalent breadth of the combined openings, Σb ded, is to be deducted, see to and Figure Sniped ends Stiffeners with sniped ends may be used where dynamic loads are small and where the incidence of vibration is considered to be small, i.e. structure not in the stern area and structure not in the vicinity of engines or generators, provided the net thickness of plating supported by the stiffener, t p-net, is not less than: t p net Where: l = c 1 s spk 1000l stiffener span, in m s stiffener spacing, in mm, as defined in 2.2 P design pressure for the stiffener for the design load set being considered, in kn/m². The design load sets and method to derive the design pressure are to be taken in accordance with the following criteria, which define the acceptance criteria set to be used: a) Table in the cargo tank region b) Section 8/ in the area forward of the forward cargo tank, and in the aft end c) Section 8/ in the machinery space d) Section 8/ and as applicable for the particular structure under consideration k higher strength steel factor, as defined in Section 6/1.1.4 c 1 coefficient for the design load set being considered, to be taken as: =1.2 for acceptance criteria set AC1 and sloshing design load =1.1 for acceptance criteria set AC2 PAGE 4 OF 48

116 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Air and drain holes and scallops Air, and drain holes, and scallops and block fabrication butts are to be kept at least 200mm clear of the toes of end brackets, end connections and other areas of high stress concentration measured along the length of the stiffener toward the mid-span and 50mm measured along the length in the opposite direction. See Figure 4.3.2(b). Openings that have been fitted with closing plates, such as scallops, may be permitted in way of block fabrication butts. In areas where the shear stress is less than 60 percent of the allowable limit, alternative arrangements may be accepted. Openings are to be well-rounded. Figure 4.3.2(a) shows some examples of air and drain holes and scallops. In general, the ratio of a/b, as defined in Figure 4.3.2(a), is to be between 0.5 and 1.0. In fatigue sensitive areas further consideration may be required with respect to the details and arrangements of openings and scallops. Figure 4.3.2(a) Examples of Air and Drain Holes and Scallops b 15mm a 100mm b 25mm a b 15mm a Note The details shown in this figure are for guidance and illustration only. b - a PAGE 5 OF 48

117 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Figure 4.3.2(b) Location of Air and Drain Holes Openings to be kept clear of these areas. 3.4 Intersections of Continuous Local Support Members and Primary Support Members General When, in the following locations, the calculated direct stress, σ w, in the primary support member web stiffener according to exceeds 80% of the permissible values a soft heel is to be provided in way of the heel of primary support member web stiffeners: (a) connection to shell envelope longitudinals below the scantling draught, T sc (b) connection to inner bottom longitudinals. A soft heel is not required at the intersection with watertight bulkheads and primary support members, where a back bracket is fitted or where the primary support member web is welded to the stiffener face plate. The soft heel is to have a keyhole, similar to that shown in Figure 4.3.6(c). PAGE 6 OF 48

118 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 SECTION 6 - MATERIALS AND WELDING 1 STEEL GRADES 1.2 Application of Steel Materials Operation in areas with low air temperature For ships intended to operate for long periods in areas with a lowest daily mean air temperature lowest mean daily average temperature below 10 degrees C (i.e. regular service during winter to Arctic or Antarctic waters) the materials in exposed structures will be specially considered. PAGE 7 OF 48

119 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Table Material Class or Grade of Structural Members Structural member category Material Class or Grade Within 0.4L Outside 0.4L Amidships Secondary Longitudinal bulkhead strakes, other than those belonging to primary category Deck plating exposed to weather other than that belonging Class I Grade A (8) /AH to primary or special category Side plating Primary Bottom plating including keel plate Strength deck plating, excluding that belonging to the special category (10) (11) Continuous longitudinal members above strength deck, excluding longitudinal hatch coamings (11) Uppermost strake in longitudinal bulkheads (10) Vertical strake (hatch side girder) and upper sloped strake in top wing tank Special Sheer strake at strength deck (1)(2)(3)(10) (11) Stringer plate in strength deck (1)(2)(3)(10) (11) Deck strake at longitudinal bulkhead, excluding deck plating in way of inner hull longitudinal bulkhead (2)(4)(10) (11) Strength deck plating at outboard corners of cargo hatch openings (11) Bilge strake (2)(6) Continuous longitudinal hatch coamings (11) Other Categories Plating for stern frames, rudder horns and shaft brackets Longitudinal strength members of strength deck plating for ships with single strength deck (11) Strength members not referred to in above categories (9) Class II Class III Grade B /AH Grade A (8) /AH Grade A (8) /AH Class II (Class I outside 0.6L amidships) Class II - Grade A (8) /AH Note 1. Not to be less than E/EH within 0.4L amidships in vessels with length, L, exceeding 250m. 2. Single strakes required to be of material class III or E/EH are, within 0.4L amidships, to have breadths not less than L mm, but need not be greater than 1800mm. 3. A radius gunwale plate may be considered to meet the requirements for both the stringer plate and the sheer strake, provided it extends generally 600mm inboard and vertically. 4. For tankers having a breadth, B, exceeding 70m, the centreline strake and the strakes in way of the longitudinal bulkheads port and starboard, are to be class III. 5. (void) 6. To be not lower than D/DH within 0.6L amidships of vessels with length, L, exceeding 250m. 7. (void) 8. Grade B/AH to be used for plate thickness more than 40 mm. For engine foundation heavy plates, Grade B/AH to be used for plate thickness more than 30mm. However, engine foundation heavy plates outside 0.6L amidships may be of Grade A/AH. 9. The material class used for reinforcement and the quality of material (i.e. whether normal or higher strength steel) used for welded attachments, such as spill protection bars and bilge keel, is to be similar to that of the hull envelope plating in way. Where attachments are made to round gunwale plates, special consideration will be given to the required grade of steel, taking account of the intended structural arrangements and attachment details. 10. The material class for deck plating, sheer strake and upper strake of longitudinal bulkhead within 0.4L amidships is also to be applied at structural breaks of the superstructure, irrespective of position. 11. To be not lower than B/AH within 0.4L amidships for ships with single strength deck. PAGE 8 OF 48

120 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Hull Protection For ships contracted for construction on or after 8 December 2006, the date of IMO adoption of the amended SOLAS Regulation II-1/3-2, by which an IMO Performance standard for protective coatings for ballast tanks and void spaces will be made mandatory, the coatings of internal spaces subject to the amended SOLAS Regulation are to satisfy the requirements of the IMO performance standard. For ships contracted for construction on or after 1 July 2012, the IMO performance standard is to be applied as interpreted by IACS UI SC 223 and UI SC 227. In applying IACS UI SC 223, Administration is to be read to be the Classification Society. PAGE 9 OF 48

121 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY CORROSION ADDITIONS Figure Corrosion Addition, tcorr, for Typical Structural Elements Within the Cargo Tank Internals in upper portion of WBT 4.0 Long stiff 4.0 Long bhd 4.0 Long bhd stiff 4.0 Deck trans web 4.0 Face plate 4.0 Deck 4.0 Sheerstrake 3.5 To 3m Below Top of Tank Inner skin 3.0 Long stiff 3.0 Long bhd stiff 2.5 Long bhd 2.5 Faceplate 3.5 Web 2.5 Inner skin 4.0 Stringer 3.0 Sideshell 3.0 (see note) Webplate 3.0 Hopper 3.0 Faceplate 3.5 Long girders 3.0 Long stiff. 3.0 Bottom and bilge 3.0 Inner bottom 4.0 Note 1. Corrosion additions are given for a standard configuration and without heated cargo mm to be added for side plating in the quay contact region defined in Section 8/Figure PAGE 10 OF 48

122 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Figure Corrosion Addition, tcorr, for Typical Structural Elements Within the Cargo Tank Internals in upper portion of WBT 4.0 Long stiff 4.0 Long bhd 4.0 Long bhd stiff 4.0 Deck trans web 4.0 Face plate 4.0 Deck 4.0 Sheerstrake 3.5 To 3m Below Top of Tank Inner skin 3.0 Long stiff 3.0 Long bhd stiff 2.5 Long bhd 2.5 Faceplate 3.5 Web 2.5 Inner skin 4.0 Stringer 3.0 Sideshell 3.0 (see note) Webplate 3.0 Hopper 3.0 Faceplate 3.5 Long girders 3.0 Long stiff. 3.0 Bottom and bilge 3.0 Inner bottom 4.0 Note 1. Corrosion additions are given for a standard configuration and without heated cargo mm to be added for side plating in the quay contact region defined in Section 8/Figure New Note 3. The distance 3m below top of tank is to be measure parallel to the deck. PAGE 11 OF 48

123 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY FABRICATION 4.1 General Fabrication standard The fabrication standard is to include information, to establish the range and the tolerance limits, for the items specified as follows: (a) Cutting edge the slope of the cut edge and the roughness of the cut edges (b) Flanged longitudinals and brackets and built-up sections the breadth of flange and depth of web, angle between flange and web, and straightness in plane of flange or at the top of face plate (c) Pillars the straightness between decks, and cylindrical structure diameter (d) Brackets and small stiffeners the distortion at the free edge line of tripping brackets and small stiffeners (e) Sub-assembly stiffeners details of snipe end of secondary face plates and stiffeners (f) Plate assembly for flat and curved blocks the dimensions (length and breadth), distortion and squareness, and the deviation of interior members from the plate (g) Cubic assembly in addition to the criteria for plate assembly, twisting deviation between upper and lower plates, for flat and curved cubic blocks (h) Special assembly the distance between upper and lower gudgeons, distance between aft edge of propeller boss and aft peak bulkhead, twist of stern frame assembly, deviation of rudder from shaft centreline, twist of rudder plate, and flatness, breadth and length of top plate of main engine bed. Where The final boring out of the propeller boss and stern frame, skeg or solepiece is carried out at a late stage of construction, it is to be carried out after completing the major part of the welding of the aft part of the ship. Where block boring is used, the shaft alignment is to be carried out using a method and sequence submitted to and recognized by the Classification Society., and tthe fit-up and alignment of the rudder, pintles and axles, are to be carried out after completing the major part of the welding of the aft part of the ship. The contacts between the conical surfaces of pintles, rudder stocks and rudder axles are to be checked before the final mounting. (i) Butt joints in plating alignment of butt joint in plating (j) Cruciform joints PAGE 12 OF 48

124 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 alignment measured on the median line and measured on the heel line of cruciform joints (k) Alignment of interior members alignments of flange of T longitudinals, alignment of panel stiffeners, gaps in T joints and lap joints, and distance between scallop and cut outs for continuous stiffeners in assembly and in erection joints (l) Keel and bottom sighting deflections for whole length of the ship, and for the distance between two adjacent bulkheads, cocking-up of fore body and of aft body, and rise of floor amidships (m) Dimensions dimensions of length between perpendiculars, moulded breadth and depth at midship, and length between aft edge of propeller boss and main engine (n) Fairness of plating between frames deflections between frames of shell, tank top, bulkhead, upper deck, superstructure deck, deck house deck and wall plating (o) Fairness of plating in way of frames deflections of shell, tank top, bulkhead, strength deck plating and other structures measured in way of frames PAGE 13 OF 48

125 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY COMBINATION OF LOADS 6.2 Design Load Combination SECTION 7 - LOADS General The design load combinations are given in Table Table Design Load Combinations Design Load Combination S S + D A Load components M v-total M sw-harb M sw-sea + M wv - M h-total - M h - Q Q sw-harb Q sw-sea + Q wv - Weather Deck - P wdk-dyn - P ex Hull envelope P hys P hys +P wv-dyn - P in P dk Ballast tanks (BWE with sequential filling method) Ballast tanks (BWE with flowthrough method) Cargo tanks including cargo tanks designed for filling with water ballast Other tanks with liquid filling the greater of a) P in-test b) P in-air + P drop the greater of a) P in-test b) P in-air + P drop the greater of a) P in-test b) P in-tk + P valve the greater of a) P in-test b) P in-air P in-tk +P in-dyn P in-air + P drop + P in-dyn P in-tk +P in-dyn P in-tk + P valve P in-dyn P in-tk +P in-dyn P in-flood P in-flood - P in-flood Watertight boundaries - - P in-flood Internal decks for dry spaces P stat P stat + P dk-dyn - Decks for heavy units F stat F stat + F dk-dyn - PAGE 14 OF 48

126 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Table (Continued) Design Load Combinations Note: 1. Separate load requirements may be specified in strength assessment (FEM) and scantling requirements. Where: M v-total design vertical bending moment, in knm M sw-perm-harb permissible hull girder hogging and sagging still water bending moment envelopes for harbour/sheltered water operation, in knm see M sw-perm-sea permissible hull girder hogging and sagging still water bending moment envelopes for seagoing operation, in knm see M wv vertical wave bending moment for a considered dynamic load case, see in knm M h-total design horizontal bending moment, in knm M h horizontal wave bending moment for a considered dynamic load see case, in knm Q design vertical shear force, in kn Q sw-perm-harb permissible hull girder positive and negative still water shear force limits for harbour/sheltered water operation, in kn see Q sw-perm-sea permissible hull girder positive and negative still water shear force limits for seagoing operation, in kn see Q wv vertical wave shear force for a considered dynamic load case, in kn see P ex design sea pressure, in kn/m 2 P hys static sea pressure at considered draught, in kn/m 2 see P wv-dyn dynamic wave pressure for a considered dynamic load case, in see kn/m 2 P wdk-dyn green sea load for a considered dynamic load case, in kn/m 2 see P in design tank pressure, in kn/m 2 P in-test tank testing pressure, in kn/m 2 see P in-air static tank pressure in the case of overfilling or filling during flow see through ballast water exchange, in kn/m 2 P drop added overpressure due to liquid flow through air pipe or see overflow pipe, in kn/m 2 P valve setting of pressure relief valve, in kn/m 2 see P in-tk static tank pressure, in kn/m 2 see P in-dyn dynamic tank pressure for a considered dynamic load case, in kn/m 2 see P in-flood pressure in compartments and tanks in flooded or damaged condition, in kn/m 2 see P stat static pressure on decks and inner bottom, in kn/m 2 see P dk design deck pressure, in kn/m 2 P dk-dyn dynamic deck pressure on decks, inner bottom and hatch covers for a considered dynamic load case, in kn/m 2 see F stat load acting on supporting structures and securing systems for heavy units of cargo, equipment or structural components, in kn see F dk-dyn dynamic load acting on supporting structures and securing systems for heavy units of cargo, equipment or structural see components, in kn PAGE 15 OF 48

127 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 SECTION 8 - SCANTLING REQUIREMENTS 1 LONGITUDINAL STRENGTH 1.1 Loading Guidance Loading Manual The following loading conditions and design loading and ballast conditions upon which the approval of the hull scantlings is based are, as a minimum, to be included in the Loading Manual: (a) Seagoing conditions including both departure and arrival conditions homogeneous loading conditions including a condition at the scantling draft (homogeneous loading conditions shall not include filling of dry and clean ballast tanks at departure condition) a normal ballast condition where: the ballast tanks may be full, partially full or empty. Where partially full options are exercised, the conditions in are to be complied with all cargo tanks are to be empty including cargo tanks suitable for the carriage of water ballast at sea the propeller is to be fully immersed, and the trim is to be by the stern and is not to exceed 0.015L, where L is as defined in Section 4/1.1.1 a heavy ballast condition where: the draught at the forward perpendicular is not to be less than that for the normal ballast condition ballast tanks in the cargo tank region or aft of the cargo tank region may be full, partially full or empty. Where the partially full options are exercised, the conditions in are to be complied with the fore peak water ballast tank is to be full. If upper and lower fore peak tanks are fitted, the lower is required to be full. The upper fore peak tank may be full, partially full or empty. all cargo tanks are to be empty including cargo tanks suitable for the carriage of water ballast at sea the propeller is to be fully immersed the trim is to be by the stern and is not to exceed 0.015L, where L is as defined in Section 4/1.1.1 any specified non-uniform distribution of loading conditions with high density cargo including the maximum design cargo density, when applicable mid-voyage conditions relating to tank cleaning or other operations where these differ significantly from the ballast conditions conditions covering ballast water exchange procedures with the calculations of the intermediate conditions just before and just after ballasting and/or deballasting any ballast tank PAGE 16 OF 48

128 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 (b) Harbour/sheltered water conditions conditions representing typical complete loading and unloading operations docking condition afloat propeller inspection afloat condition, in which the propeller shaft centre line is at least D prop /4 above the waterline in way of the propeller, where D prop is the propeller diameter (c) Additional design conditions a design ballast condition in which all segregated ballast tanks in the cargo tank region are full and all other tanks are empty including fuel oil and fresh water tanks. Guidance Note The design condition specified in (c) is for assessment of hull strength and is not intended for ship operation. This condition will also be covered by the IMO 73/78 SBT condition provided the corresponding condition in the Loading Manual only includes ballast in segregated ballast tanks in the cargo tank region Minimum requirements At the midship cross section the net vertical hull girder section modulus, Z v-min, at the deck and keel is not to be less than the rule minimum hull girder section modulus, Z v-min, defined as: 6 ( C + 0.7) 10 Z v min = 0.9kCwvL B b m 3 2 Where: k higher strength steel factor, as defined in Section 6/1.1.4 C wv wave coefficient as defined in Table L rule length, in m, as defined in Section 4/ B moulded breadth, in m, as defined in Section 4/ C b block coefficient, as defined in Section 4/ but is not to be taken as less than Assessment of hull girder shear strength Hull Girder Shear Strength The permissible positive and negative still water shear forces for seagoing and harbour/sheltered water operations, Q sw-perm-sea and Q sw-perm-harb are to satisfy: Qsw perm Qv net50 Qwv pos kn for maximum permissible positive shear force Qsw perm Qv net50 Qwv neg kn for minimum permissible negative shear force Where: PAGE 17 OF 48

129 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Q sw-perm Q v-net50 τ ij-perm Q wv-pos Q wv-neg t ij-net50 t net50 t grs t w-grs t f-grs permissible hull girder still water shear force as given in Table 8.1.4, in kn net hull girder vertical shear strength to be taken as the minimum for all plate elements that contribute to the hull girder shear capacity τ ij permtij net50 = kn 1000q v permissible hull girder shear stress, τ perm, as given in Table 8.1.4, in N/mm 2, for plate ij positive vertical wave shear force, in kn, as defined in Table negative vertical wave shear force, in kn, as defined in Table equivalent net thickness, t net50, for plate ij, in mm. For longitudinal bulkheads between cargo tanks, t net50 is to be taken as t sfc-net50 and t str-k as appropriate, see and net thickness of plate, in mm = t 0.5 grs t corr gross plate thickness, in mm. The gross plate thickness for corrugated bulkheads is to be taken as the minimum of t w-grs and t f-grs, in mm gross thickness of the corrugation web, in mm gross thickness of the corrugation flange, in mm t corr corrosion addition, in mm, as defined in Section 6/3.2 q v f i q 1-net50 I v-net50 unit shear flow per mm for the plate being considered and based on the net scantlings. Where direct calculation of the unit shear flow is not available, the unit shear flow may be taken equal to: = q 1 net50 f 10 9 i mm -1 Iv net50 shear force distribution factor for the main longitudinal hull girder shear carrying members being considered. For standard structural configurations f i is as defined in Figure first moment of area, in cm 2 cm 3,about the horizontal neutral axis of the effective longitudinal members between the vertical level at which the shear stress is being determined and the vertical extremity, taken at the section being considered. The first moment of area is to be based on the net thickness, t net50 net vertical hull girder section moment of inertia, in m 4, as defined in Section 4/ PAGE 18 OF 48

130 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Shear force correction due to loads from transverse bulkhead stringers In way of transverse bulkhead stringer connections, within areas as specified in Figure 8.1.6, the equivalent net thickness of plate used for calculation of the hull girder shear strength, t str-k, where the index k refers to the identification number of the stringer, is not to be taken greater than: τ str t str k = tsfc net50 1 mm τ ij perm Where: t sfc-net50 τ ij-perm k ij τ str effective net plating thickness, in mm, as defined in and calculated at the transverse bulkhead for the height corresponding to the level of the stringer permissible hull girder shear stress, τ perm, for plate ij = 120/k ij N/mm 2 higher strength steel factor, k, for plate ij as defined in Section 6/1.1.4 Q t str-k = N/mm 2 l str sfc net50 l str connection length of stringer, in m, see Figure Q str-k shear force on the longitudinal bulkhead from the stringer in loaded condition with tanks abreast full = 0.8 z str hdb z Fstr-k 1 hbhd str hdb = 0.8 Fstr-k 1 kn hblk F str-k total stringer supporting force, in kn, as defined in h db the double bottom height, in m, as shown in Figure h blk z str height of bulkhead, in m, defined as the distance from inner bottom to the deck at the top of the bulkhead, as shown in Figure the vertical distance from baseline to the considered stringer, in m. PAGE 19 OF 48

131 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Tapering and Structural Continuity of Longitudinal Hull Girder Elements Vertical extent of higher strength steel The vertical extent of higher strength steel, z hts, used in the deck or bottom and measured from the moulded deck line at side or keel is not to be taken less than the following, see also Figure z 190 z 1 m σ1k = hts 1 i σ perm z hts = z1 1 m σ1 Where: z 1 σ 1 σ dk σ kl distance from horizontal neutral axis to moulded deck line or keel respectively, in m to be taken as σ dk or σ kl for the hull girder deck and keel respectively, in N/mm 2 hull girder bending stress at moulded deck line given by: Msw perm sea + Mwv v = ( zdk side zna net50 ) 10 I v net50 hull girder bending stress at keel given by: Msw perm sea + Mwv v = ( zna net50 zkl ) 10 I v net N/mm 2 N/mm 2 σ perm permissible hull girder bending stress as given in Table for design load combination S+D, in N/mm 2 M sw-perm-sea M wv-v I v-net50 z dk-side z kl z NA-net50 k i permissible hull girder still water bending moment for seagoing operation, in knm, as defined in Section 7/2.1.1 hogging and sagging vertical wave bending moments, in knm, as defined in Section 7/3.4.1 M wv-v is to be taken as: M wv-hog for assessment with respect to hogging vertical wave bending moment M wv-sag for assessment with respect to sagging vertical wave bending moment net vertical hull girder moment of inertia, in m 4, as defined in Section 4/ distance from baseline to moulded deck line at side, in m vertical distance from the baseline to the keel, in m distance from baseline to horizontal neutral axis, in m higher strength steel factor for the area i defined in Figure The factor, k, is defined in Section 6/1.1.4 PAGE 20 OF 48

132 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY CARGO TANK REGION 2.5 Bulkheads Vertically corrugated bulkheads For ships with a moulded depth, see Section 4/1.1.4, less than 16m, the lower stool may be eliminated provided the following requirements, in addition to the requirements of , are complied with: (a) general: double bottom floors or girders are to be fitted in line with the corrugation flanges for transverse or longitudinal bulkheads, respectively brackets/carlings are to be fitted below the inner bottom and hopper tank in line with corrugation webs. Where this is not practicable gusset plates with shedder plates are to be fitted, see item (c) below and Figure the corrugated bulkhead and its supporting structure is to be assessed by Finite Element (FE) analysis in accordance with Section 9/2. In addition the local scantlings requirements of and and the minimum corrugation depth requirement of are to be applied. (b) inner bottom and hopper tank plating: the inner bottom and hopper tank in way of the corrugation is to be of at least the same material yield strength as the attached corrugation, and Z grade steels as given in Section 6/1.1.5 are to be used unless plate through thickness properties are documented for approval. (c) supporting structure: within the region of the corrugation depth below the inner bottom the net thickness of the supporting double bottom floors or girders is not to be less than the net thickness of the corrugated bulkhead flange at the lower end and is to be of at least the same material yield strength the upper ends of vertical stiffeners on supporting double bottom floors or girders are to be bracketed to adjacent structure brackets/carlings arranged in line with the corrugation web are to have a depth of not less than 0.5 times the corrugation depth and a net thickness not less than 80% of the net thickness of the corrugation webs and are to be of at least the same material yield strength cut outs for stiffeners in way of supporting double bottom floors and girders in line with corrugation flanges are to be fitted with full collar plates where support is provided by gussets with shedder plates, the height of the gusset plate, see h g in Figure 8.2.3, is to be at least equal to the corrugation depth, and gussets with shedder plates are to be arranged in every corrugation. The gusset plates are to be fitted in line with and between the corrugation flanges. The net thickness of the gusset and shedder plates are not to be less than 100% and 80%, respectively, of the net thickness of the corrugation flanges and are to be of at least the same material yield strength. Also see scallops in brackets, gusset plates and shedder plates in way of the connections to the inner bottom or corrugation flange and web are not permitted. PAGE 21 OF 48

133 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Table Values of C i Bulkhead At lower end of l cg At mid length of l cg At upper end of l cg Transverse Bulkhead C 1 C m1 0.80C m1 0.65C m1 Longitudinal Bulkhead C 3 C m3 0.65C m3 Where: C 1 a 1 b 1 C m1 a m1 b m1 C 3 a 3 A dt = a 1 + b but is not to be taken as less than bdk A dt = a1 b for transverse bulkhead with no lower stool, but is not to be taken 1 bdk as less than = R bt = for transverse bulkhead with no lower stool = R bt = 0.13 for transverse bulkhead with no lower stool A dt = a m1 + b but is not to be taken as less than 0.55 m1 bdk A dt = am1 b for transverse bulkhead with no lower stool, but is not to be taken m1 bdk 0.25 = R bt as less than 0.60 = for transverse bulkhead with no lower stool 0.11 = 0.25 R bt = 0.34 for transverse bulkhead with no lower stool A dl = a 3 + b but is not to be taken as less than ldk A dl = a3 b for longitudinal bulkhead with no lower stool, but is not to be 3 ldk 0.35 = 0.86 R bl taken as less than 0.55 = for longitudinal bulkhead with no lower stool PAGE 22 OF 48

134 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 b 3 C m3 a m3 b m3 R bt R bl A dt A dl A bt A bl 0.10 = R bl Table (Continued) Values of C i = 0.13 for longitudinal bulkhead with no lower stool A dl = a m3 + b but is not to be taken as less than 0.55 m3 ldk A dl = am3 b for longitudinal bulkhead with no lower stool, but is not to be m3 ldk 0.24 = R bl taken as less than 0.60 = for longitudinal bulkhead with no lower stool 0.10 = 0.12 R bl = 0.19 for longitudinal bulkhead with no lower stool A l + ib b + av t 1 1 for transverse bulkheads bib hst = bt bib A l + ib b + av l 1 1 for longitudinal bulkheads bib hsl = bl lib cross sectional area enclosed by the moulded lines of the transverse bulkhead upper stool, in m 2 = 0 if no upper stool is fitted cross sectional area enclosed by the moulded lines of the longitudinal bulkhead upper stool, in m 2 = 0 if no upper stool is fitted cross sectional area enclosed by the moulded lines of the transverse bulkhead lower stool, in m 2 cross sectional area enclosed by the moulded lines of the longitudinal bulkhead lower stool, in m 2 b av-t average width of transverse bulkhead lower stool, in m. See Figure b av-l average width of longitudinal bulkhead lower stool, in m. See Figure h st height of transverse bulkhead lower stool, in m. See Figure h sl height of longitudinal bulkhead lower stool, in m. See Figure b ib b dk breadth of cargo tank at the inner bottom level between hopper tanks, or between the hopper tank and centreline lower stool, in m. See Figure breadth of cargo tank at the deck level between upper wing tanks, or between the upper wing tank and centreline deck box or between the corrugation flanges if no upper stool is fitted, in m. See Figure l ib length of cargo tank at the inner bottom level between transverse lower stools, in m. See Figure l dk length of cargo tank at the deck level between transverse upper stools or between the corrugation flanges if no upper stool is fitted, in m. See Figure PAGE 23 OF 48

135 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Deck Structure Deck plating The thickness of the deck plating is to comply with the requirements in with the applicable lateral pressure, green sea and deck loads (void) PAGE 24 OF 48

136 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY EVALUATION OF STRUCTURE FOR SLOSHING AND IMPACT LOADS 6.3 Bottom Slamming Primary support members The net web thickness, t w-net, of primary support members adjacent to the shell is not to be less than: t w net s = 70 σ yd 235 t w net sw = 70 σ yd 235 mm Where: s w plate breadth, in mm, taken as the spacing between the web stiffening σ yd specified minimum yield stress of the material, in N/mm Bow Impact Side shell stiffeners The effective net plastic section modulus, Z pl-net, of each stiffener, in association with the effective plating to which it is attached, is not to be less than: 2 Pim slbdg Z pl net = cm 3 f C σ Where: bdg s yd P im bow impact pressure as given in Section 7/4.4 and calculated at the load calculation point defined in Section 3/5.2.2, in kn/m 2 s stiffener spacing, in mm, as defined in Section 4/2.2 l bdg f bdg n s C s effective bending span, as defined in Section 4/2.1.1, in m bending moment factor n s = = 2.0 for continuous stiffeners or where stiffeners are bracketed at both ends see for alternative arrangements permissible bending stress coefficient = 0.9 for acceptance criteria set AC3 σ yd specified minimum yield stress of the material, in N/mm 2 PAGE 25 OF 48

137 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Primary support members The net section modulus of each primary support member, Z net50, is not to be less than: Z net50 2 fbdg ptpim bslm fslm lbdg = 1000 cm 3 f bdg C σ s yd Where: f bdg-pt f slm l slm correction factor for the bending moment at the ends and considering the patch load = 3 f 8 f + 6 f 3 slm 2 slm slm patch load modification factor l = l slm bdg extent of bow impact load area along the span = A slm m, but not to be taken as greater than l bdg A slm bow impact load area, in m 2, as defined in l bdg P im b slm f bdg C s effective bending span, as defined in Section 4/2.1.4, in m bow impact pressure as given in Section 7/4.4 and calculated at the load calculation point defined in Section 3/ , in kn/m 2 breadth of impact load area supported by the primary support member, to be taken as the spacing between primary support members as defined in Section 4/2.2.2, but not to be taken as greater than l slm, in m bending moment factor = 12 for primary support members with end fixed continuous face plates, stiffeners or where stiffeners are bracketed in accordance with Section 4/3.3 at both ends permissible bending stress coefficient = 0.8 for acceptance criteria set AC3 σ yd specified minimum yield stress of the material, in N/mm 2 PAGE 26 OF 48

138 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 SECTION 9 - DESIGN VERIFICATION 1 HULL GIRDER ULTIMATE STRENGTH 1.1 General Application The scantling requirements in this Sub-Section are to be applied within 0.4L amidships to any cross section along the entire vessel s length and are in addition to all other requirements within the rules. 2 STRENGTH ASSESSMENT (FEM) 2.3 Local Fine Mesh Structural Strength Analysis Objective and scope For tankers of conventional arrangements, as a minimum requirement, the following areas in the midship cargo region are to be investigated: (a) main bracket toes and openings at critical locations and upper hopper knuckle joint of a typical transverse web frame located in the midship tank. Where a wash bulkhead is fitted, main bracket toes and openings at critical locations of transverse and vertical webs (b) main bracket toes and openings at critical locations on a typical transverse web frame adjacent to a transverse bulkhead in way of the transverse bulkhead horizontal stringers (c) main bracket toes, heels and openings at critical locations of horizontal stringers, connection of transverse bulkhead to double bottom girder or buttress of a typical transverse bulkhead (d) connections of transverse and longitudinal corrugated bulkheads to bottom stool or inner bottom and double bottom supporting structure if a lower stool is not fitted. If a gusset plate is fitted the connection between the corrugation and the upper corners of the gusset are to be assessed (e) end brackets and attached web stiffeners of typical longitudinal stiffeners of double bottom and deck, and adjoining vertical stiffener of transverse bulkhead. If longitudinal stiffeners are fitted above the deck then the connection in way of the transverse bulkhead are to be assessed The selection of critical locations on the structural members described in to perform fine mesh analysis is to be in accordance with Appendix B/ Where the stress level in areas of stress concentration on structural members not specified in exceeds the acceptance criteria of the cargo tank analysis, a fine mesh analysis is to be carried out to demonstrate satisfactory scantlings Where the geometry can not be adequately represented in the cargo tank finite element model, a fine mesh analysis may be used to demonstrate satisfactory scantlings. In such cases the average stress within an area equivalent to that specified in the cargo tank analysis (typically s by s) is to comply with the requirement given in Table See also Note 1 of Table PAGE 27 OF 48

139 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Application of scantlings to side shell, longitudinal bulkheads and inner hull longitudinal bulkheads The scantlings of plating and longitudinal stiffeners of side shell, longitudinal bulkheads and inner longitudinal bulkheads within 0.15D from the deck are to be maintained longitudinally within 0.4L amidships. The scantlings of plating and longitudinal stiffener at a given height are not to be less than the maximum of that required for the corresponding vertical location along the length of the middle tanks of the cargo tank finite element model required by Appendix B/ Outside 0.4L amidships, the scantlings of the plating and stiffeners within 0.15D from the deck may be tapered to that required by Section 8 at the ends of the cargo tank region The plate thickness of side shell, longitudinal bulkheads and inner hull longitudinal bulkheads, including hopper plating, outside 0.15D from the deck may vary along the length and height of a tank. The plate thickness away from the transverse bulkheads is not to be less than that required for the corresponding location of the middle tanks of the cargo tank finite element model required by Appendix B/ These scantlings are to be maintained for all tanks within the cargo region, other than the fore-most and aft-most cargo tanks. For the fore-most and aft-most cargo tanks, the minimum net thickness of the side shell, longitudinal bulkheads or inner hull longitudinal bulkheads (including hopper plating) plating outside 0.15D from the deck is given by: t net s = tnet mid mm s Where: t net-mid s s mid mid required net thickness for corresponding location in the midship tank, in mm spacing between longitudinal stiffeners at location under consideration, in mm spacing between longitudinal stiffeners at corresponding location in midship tank, in mm The plate thickness of side shell, longitudinal bulkheads and inner hull longitudinal bulkheads, including hopper plating, in way of transverse bulkheads required for strengthening against hull girder shear loads is not to be less than that required by Appendix B/ , B/ and B/ Within 0.15D from the deck, the plate thicknesses in way of transverse bulkheads are not to be taken as less than that required by Outside 0.15D from the deck, the plate thicknesses in way of transverse bulkheads are not to be taken as less than that required by The scantlings of longitudinal stiffeners of side shell, longitudinal bulkheads, inner longitudinal bulkheads and hopper plate at a given height, outside 0.15D from the deck, are not to be less than that required for the corresponding vertical location of the middle tanks of the cargo tank finite element model as required by Appendix B/ These scantlings are to be maintained for all tanks within the cargo region The plate thickness required for strengthening against hull girder shear loads of the side shell, longitudinal bulkheads and inner hull longitudinal bulkheads in way of a transverse bulkhead is to be taken as the greater from the corresponding vertical location of the forward and aft transverse bulkhead of the middle tanks of the cargo tank finite element model as required by Appendix B/ All relevant requirements in other sections of the Rules are also to be complied with. PAGE 28 OF 48

140 RULE CHANGE NOTICE 1 SECTION 10 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 BUCKLING AND ULTIMATE STRENGTH 1 GENERAL 1.1 Strength Criteria Scope The strength criteria are to be based on the following assumptions and limitations in respect to buckling and ultimate strength control in design: (a) the buckling strength of stiffeners is to be greater than the plate panels they support (b) the primary support members supporting stiffeners are to have sufficient inertia to prevent out of plane buckling of the primary member, see (c) all stiffeners with their associated effective plate are to have moments of inertia to provide adequate lateral stability, see (d) the proportions of local support members and primary support members are to be such that local instability is prevented (e) tripping of primary support members (e.g. torsional instability) is to be prevented by fitment of tripping brackets or equivalents, see in (f) the web plate of primary support members is to be such that elastic buckling of the plate between web stiffeners is prevented (g) for plates with openings, the buckling strength of the areas surrounding the opening or cut out and any edge reinforcements are adequate, see and PAGE 29 OF 48

141 RULE CHANGE NOTICE 1 SECTION 11 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 GENERAL REQUIREMENT 1 HULL OPENINGS AND CLOSING ARRANGEMENTS 1.4 DECK HOUSES AND COMPANIONWAYS Exposed bulkhead plating The gross thickness of plating, t blk-grs, is not to be less than that calculated from and that given by: t = 3s k mm blk-grs h des Where: s spacing of stiffeners, in m k higher strength steel factor, as defined in Section 6/1.1.4 σ yd specified minimum yield stress of the material, in N/mm 2 h des design head, in m: [( C f ) z c L 1 L 2 C4 5 ] but is not to be taken less than given below for the specified location: L /100 unprotected front bulkheads on the lowest tier L /200 elsewhere rule length, L, as defined in Section 4/ , but is not to be taken greater than 250m rule length, L, as defined in Section 4/ , but is not to be taken greater than 300m C 4 coefficient as given in Table C 5 C b1 coefficient: ( x/ L) C b1 +. ( x/ L) Cb where x/l 0.45 where x/l > 0.45 block coefficient as defined in Section 4/ , but is not to be taken as less than 0.60 or greater than For aft end bulkheads forward of amidships, C b1 may be taken as 0.80 x distance between the A.P. and the bulkhead being considered, in m. Deck house side bulkheads are to be divided into equal parts not exceeding 0.15L in length, and x is to be measured from the A.P. to the centre of each part considered L rule length, as defined in Section 4/ PAGE 30 OF 48

142 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 f as defined in Table z vertical distance from the summer load waterline measured to the middle of the plate, in m c b dh/ B1 b dh B 1 but is not to be taken as less than 1.0 for exposed machinery casing bulkheads and in no case is b dh /B 1 to be taken as less than 0.25 breadth of deck house at the position being considered, in m actual breadth of the vessel at the freeboard deck at the position being considered, in m Table Values of C 4 Bulkhead location Value of C 4 Unprotected front, lowest tier L 2 /120 Unprotected front, 2 nd tier L 2 /120 Unprotected front, 3 rd tier and above L 2 /150 Protected front, all tiers L 2 /150 Sides, all tiers L 2 /150 Aft ends, aft of amidships, all tiers (L 2 /1000) 0.8x/L Aft ends, forward of amidships, all tiers (L 2 /1000) 0.4x/L Table Values of f L, in m f, in m Note 1. This Table is based on the equations given in Table Table Origin of f Values L, in m f, in m L/300 L 150 ( L/10)( e ) [1 ( L/150) ] L/ < L < 300 ( L/10)( e ) L PAGE 31 OF 48

143 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Prevention of water passing inboard For acceptable arrangements for discharges and scuppers, see Figure Figure Diagrammatic Arrangement of Discharge and Scupper Systems General requirement where inboard end < 0.01L above SWL Discharges coming from enclosed spaces below the freeboard deck or on the freeboard deck Discharges through machinery space Alternatives where inboard end is > 0.01L above SWL > 0.02L above SWL Discharges coming from other spaces outboard end > 450mm below FB deck or < 600mm above SWL otherwise Superstructure or Deckhouse Deck FB Deck FB Deck FB Deck FB Deck FB Deck FB Deck 14 SWL TWL SWL SWL SWL SWL SWL Symbols: / inboard end of pipes outboard end of pipes pipes terminating on the open deck non return valve without positive means of closing non return valve with positive means of closing controlled locally valve controlled locally / control of the valves are to be in an approved position remote control normal thickness substantial thickness L in Figure to be amended to L L PAGE 32 OF 48

144 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY EQUIPMENT 4.1 Equipment Number Calculation Requirements Anchors and chains are to be in accordance with Table and the quantity, mass and sizes of these are to be determined by the equipment number (EN), given by: EN = 2/ 3 + 2Bh dk A Where: moulded displacement, in tonnes, as defined in Section 4/ B moulded breadth, in m, as defined in Section 4/ h dk h FB h 1, h 2, h 3 h n h FB + h 1 + h 2 + h , as shown in Figure In the calculation of h, sheer, camber and trim may be neglected freeboard from the summer load waterline amidships, in m height on the centreline of each tier of houses having a breadth greater than B/4, in m. A profile area of the hull, superstructure and houses above the summer load waterline which are within the length L, in m 2. Superstructures or deck houses having a breadth equal to or less than B/4 at any point may be excluded. With regard to determining A, when a screen or bulwark is more than 1.5m high, the area shown in Figure as A 2 is to be included in A L rule length, as defined in Section 4/ Notes (a) Screens or bulwarks 1.5 m or more in height are to be regarded as parts of houses when determining h and A. (b) If a house having a breadth greater than B/4 is above a house with a breadth of B/4 or less then the wide house is to be included but the narrow house ignored. 5 TESTING PROCEDURES 5.1 TANK TESTING Leak testing All boundary welds, erection joints, and penetrations including pipe connections, except welds made by automatic processes are to be examined in accordance with the approved procedure and under a pressure of at least 0.15bar with a leak indicating solution (e.g. soapy water solution). Pressures greater than 0.20bar are not recommended. PAGE 33 OF 48

145 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Table Testing Requirements for Tanks and Boundaries Structures to be Type of Hydrostatic testing head or Remarks tested testing pressure 1 Double Bottom Tanks Structural (1) The greater of Tank boundaries - to the top of overflow, or tested from at least - to the bulkhead deck one side 2 Double Side Tanks Structural (1) The greater of - to the top of overflow, or - to 2.4m above top of tank (2) 3 Cargo Tanks Structural (1) The greatest of - to the top of overflow, - to 2.4m above top of tank (2), or Fuel Oil Bunkers Structural (1) - to the top of tank (2) plus setting of any pressure relief valve 4 Cofferdams Structural (3) The greater of - to the top of overflow, or - to 2.4m above top of cofferdam 5a Peak Tanks Structural The greater of - to the top of overflow, or - to 2.4m above top of tank (2) 5b Fore Peak not used as a tank 5c Aft Peak not used as a tank 6 Watertight Bulkheads in way of dry space 7 Watertight Doors below freeboard or bulkhead deck 8 (void) 9 Watertight hatch covers of tanks on combination carriers 10 Weathertight Hatch Covers, Doors and other Closing Appliances 11 Shell plating in way of pump room Refer to SOLAS II.1 Reg.14 Leak Hose (4) Hose Structural testing Hose (4) Visual examination The greater of: - to 2.4m above the top of hatch cover, or - setting pressure of the pressure relief valve Tank boundaries tested from at least one side Tank boundaries tested from at least one side Aft peak tank test to be carried out after installation of stern tube. Including steps and recesses For testing before installation (5) At least every second hatch cover is to be tested To be carefully examined with the vessel afloat PAGE 34 OF 48

146 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Table (Continued) Testing Requirements for Tanks and Boundaries Structures to be tested Type of testing Hydrostatic testing head or pressure Remarks 12 Chain Locker (aft Collision Bulkhead) Structural To the top of chain locker spurling pipe 13 Independent Tanks Structural The greater of - to the top of overflow, or - to 0.9 m above top of tank 14 Ballast Ducts Structural Ballast pump maximum pressure or setting of any relief valve for the ballast duct if that is less 15 Hawse Pipes Hose Note 1. Leak or hydropneumatic testing may be accepted under the conditions specified in 5.1.5, provided that at least one tank for each type is structurally tested, and selected in connection with the approval of the design. In general, the structural testing need not be repeated for subsequent vessels of a series of identical new buildings unless the Surveyor deems the repetition necessary. The structural testing of cargo space boundaries and tanks for segregated cargoes or pollutants on subsequent vessels of a series of identical new buildings are to be in accordance with the requirements of the individual Classification Society. 2. Top of tank is defined as the deck forming the top of the tank excluding hatchways. 3. Leak testing in accordance with may be accepted, except that hydropneumatic testing may be required in consideration of the construction techniques and welding procedures employed. 4. Where hose testing is impractical due to the stage of outfitting (machinery, cables, switchboard, insulation etc.), it may be replaced at the individual Society s discretion, by a careful visual examination of all the crossings and welded joints. A dye penetrant test, leak test or ultrasonic leak test may be required. 5. Before installation (i.e. normally at manufacture) the watertight access doors or hatches are to be hydrostatically tested with a head of water equivalent to the bulkhead deck at centre, from the side which is most prone to leakage. The acceptance criteria are as follows: no leakage for doors or hatches with gaskets a maximum water leakage of one litre per minute for doors or hatches with metallic sealing. 6. If leak or hydropneumatic testing is carried out, arrangements are to be made to ensure that no pressure in excess of 0.30 bar is applied. PAGE 35 OF 48

147 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Appendix A Hull Girder Ultimate Strength 2 CALCULATION OF HULL GIRDER ULTIMATE CAPACITY 2.2 Simplified Method Based on an Incremental-iterative Approach Assumptions and modelling of the hull girder cross-section In applying the procedure described in 2.2.1, the following assumptions are to be made: (a) The ultimate strength is calculated at a hull girder transverse section between two adjacent transverse webs. (b) The hull girder transverse section remains plane during each curvature increment. (c) The material properties of steel are assumed to be elastic, perfectly plastic. (d) The hull girder transverse section can be divided into a set of elements which act independently of each other The elements making up the hull girder transverse section are: (a) longitudinal stiffeners with attached plating, the structural behaviour is given in (b) transversely stiffened plate panels, the structural behaviour is given in (c) hard corners, as defined in , the structural behaviour is given in The following structural areas are to be defined as hard corners: (a) the plating area adjacent to intersecting plates (b) the plating area adjacent to knuckles in the plating with an angle greater than 30 degrees. (c) plating comprising rounded gunwales An illustration of hard corner definition for girders on longitudinal bulkheads is given in Figure A.2.3. The hard corner size is defined in The size and modelling of hard corner elements is to be as follows: (a) it is to be assumed that the hard corner extends up to s/2 from the plate intersection for longitudinally stiffened plate, where s is the stiffener spacing (b) it is to be assumed that the hard corner extends up to 20t grs from the plate intersection for transversely stiffened plates, where t grs is the gross plate thickness. Note (a) For transversely stiffened plate, the effective breadth of plate for the load shortening portion of the stress-strain curve is to be taken as the full plate breadth, i.e. to the intersection of other plates not from the end of the hard corner if any. The area on which the value of σ CR5 defined in applies is to be taken as the breadth between the hard corners, i.e. excluding the end of the hard corner if any. (b) For longitudinally stiffened plate, the effective breadth of attached plate is equal to the mean spacing of the ordinary stiffener when the panels on both sides of the stiffener are longitudinally stiffened, or equal to the breadth of the longitudinally stiffened panel when the panel on one side of the stiffener is longitudinally stiffened and the other panel is of the transversely stiffened. PAGE 36 OF 48

148 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Where the plate members are stiffened by non-continuous longitudinal stiffeners, the non-continuous stiffeners are considered only as dividing a plate into various elementary plate panels Openings are to be considered in accordance with Section 4/ Where attached plating is made of steels having different thicknesses and/or yield stresses, an average thickness and/or average yield stress obtained by the following formula are to be used for the calculation: (a) t1 s1 + t2s2 t = s (b) σ ydp σ = ydp 1t1s1 + σ ts t s ydp2 2 2 Where: t 1, s 1, t 2, s 2, σ ydp1, σ ydp2, s, see Figure A.1.X. Figure A.1.X Definitions 2.3 Stress-strain Curves σ-ε (or Load-end Shortening Curves) Plate panels and stiffeners Plate panels and stiffeners are assumed to fail according to one of the modes of failure specified in Table A.2.1. The relevant stress-strain curve σ-ε is to be obtained for lengthening and shortening strains according to Table A Where the plate members are stiffened by non-continuous longitudinal stiffeners, the stress of the element is to be obtained in accordance with to 2.3.7, taking into account the non-continuous longitudinal stiffener. In calculating the total forces for checking the hull girder ultimate strength, the area of non-continuous longitudinal stiffener is to be assumed as zero Where openings are provided in the plate panel, the considered area of the element is to be obtained by deducting the opening area from the plating in calculating the total force for checking the hull girder ultimate strength. Openings are to be considered in accordance with Section 4/ PAGE 37 OF 48

149 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Elasto-plastic failure of structural elements The equation describing the stress-strain curve σ-ε or the elasto-plastic failure of structural elements is to be obtained from the following formula, valid for both positive (compression or shortening) of hard corners and negative (tension or lengthening) strains of all elements (see Figure A.2.4): σ = Φ σ yd σ = Φ σ yda Where: Φ ε ε E ε yd edge function: Φ = -1 for ε < -1 Φ = ε for -1 < ε < 1 Φ = 1 for ε > 1 relative strain: ε E ε = ε yd element strain strain corresponding to yield stress in the element: σ ε yd = E yd σ ε yd = E yda σ yd specified minimum yield stress of the material, in N/mm 2 σ yda equivalent minimum yield stress of the considered element, in N/mm 2 σ ydp Ap net50 + σ yds As net50 σ yda = A + A p net50 s net50 σ ydp σ yds specified minimum yield stress of the material of the plate, in N/mm 2 specified minimum yield stress of the material of the stiffener, in N/mm 2 A p-net50 net sectional area of attached plating, in cm 2 A s-net50 Note net sectional area of the stiffener without attached plating, in cm 2 The signs of the stresses and strains in this Appendix are opposite to those in the rest of the Rules PAGE 38 OF 48

150 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Figure A.2.4 Example of Stress Strain Curves σ-ε a) Stress strain curve σ-ε for elastic, perfectly plastic failure of a hard corner σ σ yda σ yd compression or shortening ε tension or lengthening -σ yd -σ yda b) Typical stress strain curve σ-ε for elasto-plastic failure of a stiffener σ σ yda σ yd compression or shortening ε tension or lengthening -σ yd -σ yda PAGE 39 OF 48

151 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY Beam column buckling The equation describing the shortening portion of the stress strain curve σ CR1 -ε for the beam column buckling of stiffeners is to be obtained from the following formula: 2 A s net beff pt net50 σ = CR1 Φσ C1 N/mm 2 2 As net st net50 Where: Φ edge function defined in A s-net50 net area of the stiffener, in cm 2, without attached plating σ C1 critical stress, in N/mm 2 : σ σ σ σ C1 C1 C1 C1 σ E1 = ε σ ydε = σ yd 1 4σ E1 σ E1 = ε = σ ydb σ ydbε 1 4σ E1 for σ yd σ E1 ε 2 for σ yd σ E1 > ε 2 for for σ σ E1 E1 ε relative strain defined in σ 2 σ > 2 σ E1 Euler column buckling stress, in N/mm 2 : 2 IE net50 4 σ 1 = 10 E π E 2 A l E net50 stf E modulus of elasticity, 2.06 x 10 5 N/mm 2 I E-net50 b eff-s net moment of inertia of stiffeners, in cm 4, with attached plating of width b eff-s effective width, in mm, of the attached plating for the stiffener: b b eff s eff s s = β = s p for for β > 1.0 p β 1.0 p ydb ydb ε ε β p s = t net50 s = t net50 εσ εσ E E yd ydp s t net50 A E-net50 l stf plate breadth, in mm, taken as the spacing between the stiffeners, as defined in Section 4/2.2.1 net thickness of attached plating, in mm net area, in cm 2, of stiffeners with attached plating of width b eff-p span of stiffener, in m, equal to spacing between primary support members PAGE 40 OF 48

152 RULE CHANGE NOTICE 1 b eff-p effective width, in mm, of the plating: b b eff p eff p = 2 s β p β p = s for for β > 1.25 β 1.25 p p COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 σ ydb equivalent minimum yield stress of the considered element, in N/mm 2 σ ydb σ = ydp A A l pe net50 pe l pe net50 pe + σ + A yds A s net50 se l s net50 se l A pe-net50 effective area, in cm 2 A 2 pe net50 = 10 beff stnet50 σ ydp σ yds l pe l se specified minimum yield stress of the material of the plate, in N/mm 2 specified minimum yield stress of the material of the stiffener, in N/mm 2 distance, in mm, measured from the neutral axis of the stiffener with attached plate of width, b eff-s, to the bottom of the attached plate distance, in mm, measured from the neutral axis of the stiffener with attached plate of width, b eff-s, to the top of the stiffener Torsional buckling of stiffeners The equation describing the shortening portion of the stress-strain curve σ CR2 -ε for the lateral-flexural buckling of stiffeners is to be obtained according to the following formula: σ CR2 s net50 2 As net50σ C st net50σ CP = Φ N/mm 2 2 A + 10 st net50 Where: Φ edge function defined in A s-net50 net area of the stiffener, in cm 2, without attached plating σ C2 critical stress, in N/mm 2 : σ σ σ σ C2 C2 C2 C2 σ E2 = ε σ ydε = σ yd 1 4σ E2 σ E2 = ε σ ydsε = σ yds 1 4σ E2 for σ yd σ E2 ε 2 for σ yd σ E2 > ε 2 for σ yds σ E2 ε 2 for σ yds σ E2 > ε 2 σ E2 Euler torsional buckling stress, in N/mm 2 σ E2= σ ET PAGE 41 OF 48

153 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 σ ET reference stress for torsional buckling, in N/mm 2, defined in Section 10/ , calculated based on gross thickness minus the corrosion addition 0.5t corr. ε relative strain defined in s plate breadth, in mm, taken as the spacing between the stiffeners, as defined in Section 4/2.2.1 t net50 σ CP net thickness of attached plating, in mm ultimate strength of the attached plating for the stiffener, in N/mm 2 : σ σ CP CP = 2 σ β p β p = σ yd yd for for β > 1.25 β 1.25 p p σ σ CP CP = σ 2 β p β p = σ ydp ydp for for β > 1.25 p β 1.25 p β p coefficient defined in σ ydp σ yds specified minimum yield stress of the material of the plate, in N/mm 2 specified minimum yield stress of the material of the stiffener, in N/mm Web local buckling of stiffeners with flanged profiles The equation describing the shortening portion of the stress strain curve σ CR3 -ε for the web local buckling of flanged stiffeners is to be obtained from the following formula: b eff ptnet50 + dw eff tw net50 + bf t f net50 σ = Φ CR3 σ yd N/mm stnet50 + dwtw net50 + bf t 2 f net50 net50 ( d t + b t ) beff ptnet50σ ydp + w eff w net50 f f net50 σ yds σ CR3 = Φ N/mm 2 st + d t + b t Where: w w net50 f f net50 Φ edge function defined in b eff-p effective width, in mm, of the plating, defined in t net50 d w t w-net50 b f t f-net50 s net thickness of plate, in mm depth of the web, in mm net thickness of web, in mm breadth of the flange, in mm net thickness of flange, in mm plate breadth, in mm, taken as the spacing between the PAGE 42 OF 48

154 RULE CHANGE NOTICE 1 d w-eff stiffeners, as defined in Section 4/2.2.1 effective depth of the web, in mm: d d w eff w eff = d 2 β w β w = d w w for for w w β 1.25 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 β > 1.25 β w t t d w w net50 d w w net50 εσ εσ E E yd yds ε relative strain defined in Ε modulus of elasticity, 2.06 x 10 5 N/mm 2 σ ydp σ yds specified minimum yield stress of the material of the plate, in N/mm 2 specified minimum yield stress of the material of the stiffener, in N/mm Web local buckling of flat bar stiffeners The equation describing the shortening portion of the stress-strain curve σ CR4 -ε for the web local buckling of flat bar stiffeners is to be obtained from the following formula: 2 st net50σ CP + 10 As net50σ C 4 σ = CR4 Φ 2 stnet As net50 Where: Φ edge function defined in σ CP ultimate strength of the attached plating, in N/mm 2, defined in σ C4 critical stress, in N/mm 2 : σ σ σ σ C4 C4 C4 C4 σ E4 = ε σ ydε = σ yd 1 4σ E4 σ E4 = ε σ ydsε = σ yds 1 4σ E4 for σ yd σ E4 ε 2 for σ yd σ E4 > ε 2 for σ yds σ E4 ε 2 for σ yds σ E4 > ε 2 σ E4 Euler buckling stress, in N/mm 2 : σ E t 4 = w net 50 ε relative strain defined in d w 2 PAGE 43 OF 48

155 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 A s-net50 net area of stiffener, in cm 2, see t w-net50 d w s t net50 σ yds net thickness of web, in mm depth of the web, in mm plate breadth, in mm, taken as the spacing between the stiffeners, as defined in Section 4/2.2.1 net thickness of attached plating, in mm specified minimum yield stress of the material of the stiffener, in N/mm Buckling of transversely stiffened plate panels The equation describing the shortening portion of the stress-strain curve σ CR5 -ε for the buckling of transversely stiffened panels is to be obtained from the following formula: σ σ CR5 CR5 Where: 2 s s 1 Φσ yd l stf β p β p 1000lstf β p = min N/mm 2 σ yd Φ 2 s s 1 Φσ ydp l stf β 2 2 p β p 1000lstf β p = min N/mm 2 σ ydp Φ β p coefficient defined in Φ edge function defined in s plate breadth, in mm, taken as the spacing between the stiffeners, as defined in Section 4/2.2.1 l stf stiffener span, in m, equal to spacing between primary support members σ yd specified minimum yield stress of the material, in N/mm 2 σ ydp specified minimum yield stress of the material of the plate, in N/mm 2 PAGE 44 OF 48

156 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Appendix B Structural Strength Assessment 2 CARGO TANK STRUCTURAL STRENGTH ANALYSIS 2.4 Application of Loads Pressure in cargo and ballast tanks The following are to be considered when calculating the static tank pressure in cargo tanks for harbour/tank testing load cases (design combination S) as required by Section 7/Table 7.6.1: Maximum setting of pressure relief valve, P valve as defined in Section 7/ , of all cargo tanks and, where applicable, maximum h air, as defined in Section 7/ and Figure 7.2.3, of all cargo tanks in the cargo region are to be considered in the calculation of P in-test, see Section 7/ Maximum setting of pressure relief valve, P valve, as defined in Section 7/ are to be considered in design combination S and S+D as required by Section 7/Table Procedure to Adjust Hull Girder Shear Forces and Bending Moments General The procedure described in this section is to be applied to adjust the hull girder horizontal bending moment, vertical shear force and vertical bending moment distributions on the three cargo tanks FE model to achieve the required values Vertical distributed loads are applied to each frame position, together with a vertical bending moment applied to the model ends to produce the required value of vertical shear force at both the forward and aft bulkhead of the middle tank of the FE model, and the required value of vertical bending moment at a section within the length of the middle tank of the FE model. The required values are specified in A horizontal bending moment is applied to the ends of the model to produce the required target value of horizontal bending moment at a section within the length of the middle tank of the FE model. The required values are specified in Shear force and bending moment due to local loads The vertical shear forces generated by the local loads are to be calculated at the transverse bulkhead positions of the middle tank of the FE model. The maximum absolute shear force at the bulkhead position of the middle tank of the FE model is to be used to obtain the required adjustment in shear forces at the transverse bulkhead, see The vertical bending moment distribution generated by the local loads is to be calculated along the length of the middle tank of the three cargo tank FE model. The FE model can be used to calculate the shear forces and bending moments. Alternatively, a simple beam model representing the length of the 3-tank FE model with simply supported ends may be used to determine the shear force and bending moment values. PAGE 45 OF 48

157 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY For beam and oblique sea conditions, the horizontal bending moment distribution due to dynamic sea pressure and dynamic tank pressure is to be calculated along the length of the middle tank of the FE model The following local loads are to be applied for the calculation of hull girder shear forces and bending moments: (a) ship structural weight distribution over the length of the 3-tank model (static loads). Where a simple beam model is used, the weight of the structure of each tank can be distributed evenly over the length of the cargo tank. The structural weight is to be calculated based on a thickness deduction of 0.5t corr, as used in the construction of the cargo tank FE model, see (b) weight of cargo and ballast (static loads) (c) static sea pressure, dynamic wave pressure and, where applicable, green sea load. For the Design Load Combination S (harbour/tank testing load cases), only static sea pressure needs to be applied (d) dynamic tank pressure load for Design Load Combination S+D (seagoing load cases) Procedure to adjust vertical shear force distribution The required adjustment in shear forces at the transverse bulkhead positions ( Q aft and Q fwd as shown in Figure B.2.10) are to be generated by applying vertical load at the frame positions as shown in Figure B It is to be noted that vertical correction loads are not to be applied to any transverse tight bulkheads, any frames forward of the forward tank and any frames aft of the aft tank of the FE model. The sum of the total vertical correction loads applied is equal to zero The required adjustment in shear forces at the aft and forward transverse bulkheads of the middle tank of the FE model in order to generate the required shear forces at the bulkheads are given by: Q aft = - Q targ - Q aft Q fwd = Q targ - Q fwd Where: Q aft Q fwd Q targ Q aft Q fwd required adjustment in shear force at aft bulkhead of middle tank based on the maximum absolute shear force at the bulkhead required adjustment in shear force at fore bulkhead of the middle tank based on the maximum absolute shear force at the bulkhead required shear force value to be achieved at forward bulkhead of middle tank, see shear force due to local loads at aft bulkhead of middle tank, see shear force due to local loads at fore bulkhead of middle tank, see PAGE 46 OF 48

158 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Figure B.2.10 Position of Target Shear Force and Required Shear Force Adjustment at Transverse Bulkhead Positions Target Aft Bkhd Fore Bkhd Condition BM SF Bkhd pos SF Q aft SF Q fwd Bkhd Bkhd Target BM Bkhd Bkhd -Target SF (hogging) Qaft Q aft Q fwd Q fwd Hog -ve Fore -Qtarg -Qtarg - Q aft Qtarg (-ve) Qtarg Qfwd Target SF (-ve) Target BM (hogging) Bkhd -Target SF Bkhd Bkhd Q aft Q aft Hog -ve Fore -Qtarg -Qtarg Qaft Qtarg (-ve) Qtarg Qfwd Q fwd Bkhd Q fwd Target SF (-ve) Bkhd Bkhd Q fwd Bkhd Target SF (+ve) Q fwd Sag +ve Fore -Qtarg -Qtarg - Qaft Qtarg (+ve) Qtarg - Qfwd Q aft -Target SF Q aft Target BM (sagging) Bkhd Bkhd Bkhd Bkhd Bkhd Target SF (+ve) Q aft Q aft Q fwd Q fwd Sag +ve Fore -Qtarg -Qtarg - Qaft Qtarg (+ve) Qtarg - Qfwd -Target SF Target BM (sagging) Note For definition of symbols, see PAGE 47 OF 48

159 RULE CHANGE NOTICE 1 COMMON STRUCTURAL RULES FOR DOUBLE HULL OIL TANKERS, JULY 2010 Appendix C Fatigue Strength Assessment The stress range combination factors, f 1, f 2, f 3 and f 4, which are to be applied to the following zones, are given in Tables C.1.2 to C.1.4 Tables C.1.3 to C.1.5: (a) Zone M: Midship region. This zone extends over the full length of all tanks where the tank LCG lies between 0.35L and 0.8L from AP. (b) Zone A: Aft region. This zone starts at the middle of the tank immediately aft of Zone M and extends aftwards to include all the aftmost tanks. (c) Zone F: Forward region. This zone starts at the middle of the tank immediately forward of Zone M and extends forwards to include all the foremost tanks. (d) Zone AT: Aft transition region between Zone M and Zone A. The stress range combination factors are to be calculated by linear interpolation between the stress range combination factors for Zones M and A. (e) Zone FT: Forward transition region between Zone M and Zone F. The stress range combination factors are to be calculated by linear interpolation between the stress range combination factors for Zones M and F. Note Where ballast tanks, centre and wing cargo tanks do not have the same lengths e.g. if slop tank is present, the middle position is to be taken at the middle of the longer tank PAGE 48 OF 48

160 Common Structural Rules for Double Hull Oil Tankers, July 2010 Technical Background for Rule Change Notice 1 (1 July 2010 consolidated edition) Notes: (1) These Rule Changes enter into force on 1 st July (2) The Rule amendments in this document are applicable to the Common Structural Rules for Double Hull Oil Tankers, July Copyright in these Common Structural Rules for Double Hull Oil Tankers is owned by: American Bureau of Shipping Bureau Veritas China Classification Society Det Norske Veritas Germanischer Lloyd Korean Register of Shipping Lloyd's Register Nippon Kaiji Kyokai Registro Italiano Navale Russian Maritime Register of Shipping Copyright 2006 The IACS members, their affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as the IACS Members. The IACS Members, individually and collectively, assume no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant IACS Member entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

161 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 4/ SECTION 4 - BASIC INFORMATION 1. Background The proposed amendment is to correct the cross reference. Section 4/ Background The proposal is to clarify that the requirements for sniped stiffeners are also applicable to structure subjected to sloshing loads. The amendment is also in line with the principle in Section 2/ The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 946: Question #946: Q1. Is Section 4/ applicable to sloshing pressure in accordance with Section 8/ and 8/ ? In this connection, please note that our major concern is web stiffeners on the primary support members since there are many such stiffeners with sniped ends. Please also note that the definition of "P" in Section 4/ refer to Table 8.2.5, Section 8/ and 8/ but neither 8/ nor 8/ Please clarify. If affirmative, the rule text needs to be updated. Q2. If the above answer is affirmative, please also clarify which "C1" factor is to be used for sloshing pressure (e.g. 1.2 for AC1 or 1.0 for AC2)? Answer #946: A1: The requirements are applicable to sloshing pressure. The Rules will be amended to clarify this. A2: On the basis of the principle in Section 2/ a C1 factor of C1=1.2 should be utilised. 2. Impact on scantlings There is no impact on scantlings as the Rule change proposal clarifies the application of the requirements. PAGE 2 OF 36

162 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 4/ Background Section 4/ indicates "a soft heel is not required at the intersection with watertight bulkheads, where a back bracket is fitted or where the primary support member web is welded to the stiffener face plate". In this connection, while the above sentence specifies permissible omission of soft heel at intersection with "watertight bulkheads", the proposal is to apply the same provision for the intersection with ordinary primary support members, where a back bracket is fitted or where the primary support member web is welded to the stiffener face plate. The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 985: RCP #985: Section 4/ indicates "a soft heel is not required at the intersection with watertight bulkheads, where a back bracket is fitted or where the primary support member web is welded to the stiffener face plate". In this connection, while the above sentence specifies permissible omission of soft heel at intersection with "watertight bulkheads", we presume that the same provision can be also applied for the intersection with ordinary primary support members, where a back bracket is fitted or where the primary support member web is welded to the stiffener face plate, Please note that the last part of the above sentence also indicates "primary support member web is welded to the stiffener face plate", which may not be at "watertight bulkheads". Please confirm, and update the Rule text, as appropriate. If it should be limited to watertight bulkhead intersection only, please advise the reason. Answer #985: We agree with your interpretation. The Rules will be amended at the next opportunity. 2. Impact on scantlings There is no impact on scantlings as the Rule change proposal clarifies the application of the requirements. PAGE 3 OF 36

163 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 6/ SECTION 6 - MATERIALS AND WELDING 1. Background The proposed amendment is to correct the definition of the temperature. Section 6/Table 6.1.3, category Special 1. Background The proposed amendment is to bring the Rules in line with Table 1 of IACS UR S6 Rev.5. The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 942: RCP #942: RCP regarding the material class specified in Table of CSR Tanker. In table of CSR Tanker, deck strakes at longitudinal bulkheads are defined as "SPECIAL". On the other hand, according to IACS UR S6 Rev. 5, deck strakes at longitudinal bulkheads, excluding deck plating in way of the inner skin bulkheads of double hull ships are defined as "SPECIAL" Hence, the material class is required to be Class III for deck strakes at longitudinal bulkheads including inner skin bulkhead within 0.4L amidships by CSR Tanker, while it is required to be Class II for deck strakes in way of the inner skin bulkheads of double hull ships within 0.4L amidships by IACS UR S6 Rev.5 because such members are defined as "PRIMARY". We believe it is reasonable that deck strakes in way of the inner skin bulkheads of double hull ships is defined as "PRIMARY" not "SPECIAL" because such members are located very close to stringer plates and sheer strakes compared to deck plates at other longitudinal bulkheads. Therefore, we would like to propose that table be amended so that it is in line with Table 1 of IACS UR S6 Rev.5. Answer #942: Your proposal is agreed with and will be considered at the next Rule Change Proposal. 2. Impact on scantlings There is no impact on scantlings. PAGE 4 OF 36

164 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 6/ Background The proposed amendment is to indicate the adoption date of the Performance standard for protective coatings for ballast tanks and void spaces by IMO, and to reference the IACS Unified Interpretation UI SC223 and SC227 for transparent application by IACS members. 2. Impact on scantlings There is no impact on scantlings. Section 6/Table 6.1.3, Note 8 1. Background The proposed amendment is to harmonise the requirements for the engine bed plates between the CSR for Double Hull Oil Tankers and the CSR for Bulk Carriers. The requirement regarding the application of materials for engine bed plates are not specified in any IACS Unified Requirements. The requirements in CSR BC and OT are based on the requirements of the developing societies behind the CSRs. Considering pre-csr service history, plan approval practice, and discussions in the IACS Hull Panel, the following was agreed to be proposed: Rules CSR Tanker CSR Bulker KC ID 711 Thickness Material Class or Grade 0.4L Outside 0.6L < 40 mm A/AH A/AH > 40 mm B/AH A/AH - Class I CSR Bulker Proposal RCP2 within 0,6L Class I A/AH Harmonised < 30 mm A/AH A/AH CSR > 30 mm B/AH A/AH 2. Impact on scantlings There is no impact on scantlings. Section 6/Figure Background The proposed amendment is to clarify how the 3 metre line from top of tank should be measured. 2. Impact on scantlings There is no impact on scantlings as the purpose of the Rule change proposal is to clarify top of tank and the 3m line. PAGE 5 OF 36

165 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 6/ Background The proposed amendment is to provide clarification for the requirements for in-place boring and block boring method. This proposed amendment is based on questions raised by shipyards which traditionally perform block boring. The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID 1083: Question #1083: Section 6/ (h) requires "The final boring out of the propeller boss and stern frame, skeg or solepeice fit-up and alignment of the rudder, pintles and axles, are to be carried out after completing the major part of the welding of the aft part of the ship. The contact between the conical surfaces of the pintles, rudder stock and rudder axles are to be checked before the final mounting." We note that the first sentence of this comes from the LR Rules Pt. 3, Ch. 1, Sec (July 2001 Edition). Regarding the first sentence, "The final boring out of the propeller boss and stern frame, skeg or solepeice fit-up and alignment of the rudder, pintles and axles, are to be carried out after completing the major part of the welding of the aft part of the ship." We note that one major shipbuilder carries out shaft alignment work in block stage and has done this successfully for many years. We contend the above be open to alternative procedures. Further such items as indicated in the requirements "The final boring out of the propeller boss and stern frame, skeg or solepeice fit-up and alignment of the rudder, pintles and axles, are to be carried out after completing the major part of the welding of the aft part of the ship. The contact between the conical surfaces of the pintles, rudder stock and rudder axles are to be checked before the final mounting.", are fabrication issues that need not be specifically addressed in the Common Structural Rules. It is believed that this text should be removed from the Rules or that the Rules clearly permit alternative procedures for confirming such alignment. Your prompt reply on this matter would be highly appreciated. Answer #1083: The Rules state that alignment should be carried out after completing the major part of the welding of the aft part of the ship. An alternative procedure to the shaft alignment may be accepted and should be reviewed by the Classification Society. As for the pintle this is a local system which would be relatively unaffected by block assembly and floating out provided all the work in the block has been completed. 2. Impact on scantlings There is no impact on scantlings. PAGE 6 OF 36

166 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 7/ Background SECTION 7 - LOADS A minimum setting of pressure relief valve is given in the Rules as 25 kn/m 2. The minimum value is applied in design load combination S only. The Rules are not clear how to apply a proposed setting of the pressure relief valve value higher than the Rule minimum. The proposal clarifies this aspect. The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 1110: Interpretation Request #1110: As per Table and Appendix B/ of the Rules with the referenced section 7/ , we understand that the relief valve pressures are subject to static conditions only for local scantlings & FE analysis requirements respectively, i.e setting pressure relief valve does not need to be considered in static + dynamic conditions. We understand that the same is true even though the designed setting pressure of relief value is higher than 25KN/m2. In that case, does any dynamic effect of the excessive pressure have to be considered? For instance, if the setting of pressure relief is 70 KN/m2, do we have to consider the additional 45 KN/m2 in S+D conditions? Answer #1110: The Rule minimum relief valve pressure is Pvalve=25kN/m2. Yes; the additional pressure above the Rule minimum is to be considered so pressure relief valve of 70 KN/m2 for "S" and 45 KN/m2 for "S+D" conditions. PAGE 7 OF 36

167 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 8/ Background SECTION 8 - SCANTLING REQUIREMENTS The requirement of not having any dry or clean ballast for the seagoing homogeneous loading condition at scantling draft only applies to the departure condition. Ballast may be used in mid-voyage and arrival conditions to correct the trim due to reduction of fuel oil. The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 947: RCP #947: With regard to the loading conditions, including both departure and arrival, to be included in the Loading Manual, CSR Tanker Sec.8/ (a) specifies that homogeneous loading conditions at the scantling draft shall not include the filling of dry and clean ballast tanks. However, paragraph c of the Technical Background for Section 8/1 of CSR Tanker is as follows: The requirement of not having any dry or clean ballast for the seagoing homogeneous loading condition at scantling draft only applies to the departure condition. Ballast may be used in mid-voyage and arrival conditions to correct the trim due to reduction of fuel oil Therefore, the application of the requirement is not clear because of the discrepancy between the current requirement and the Technical Background. Our understanding is that it is appropriate to apply the requirement only to the departure condition according to the Technical Background. Please confirm. If necessary, please amend the rule s text to clarify this. Answer #947: Your proposal has been agreed with. The Rules will be amended at the next opportunity. 2. Impact on scantlings There is no impact on scantlings as the purpose of the Rule change proposal is to clarify the loading conditions to be included in the Loading Manual. PAGE 8 OF 36

168 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 8/ Background The proposed amendment is to correct the cross reference. Section 8/ Background The proposed amendment is to correct the unit of q 1-net50. Section 8/ Background The proposed amendment is to correct a misprint. Section 8/ Background The modification is proposed to apply the varying allowable stress along the ship length for the calculation of vertical extent of higher strength steel, instead of 190/k. In case of checking the vertical extent of higher strength steel at 0.1L (or 0.9L), 140/k, not 190/k, would be applied. This is consistent with the intention of the Rules; the permissible hull girder stresses are given in Table The proposed amendment is in line with the answer provided in the IACS CSR Knowledge Centre KC ID: 909: Interpretation Request #909: 8/1.6.3 Vertical extent of higher strength steel: We have been checking this requirement even for outside of 0.4L area. However, since permissible hull girder bending stress for outside 0.4L area is not 190/k as shown in Table 8.1.3, we checked vertical extent of higher strength steel zone modifying the formula of 190/k1 in 8/ with the permissible hull girder bending stress at the check point required in Table Please clarify and change the rule if it is necessary. Answer #947: For the application of 8/ , the permissible hull girder bending stress for outside 0.4L amidships is to be in accordance with the Table We will update the Rules to clarify the application. 2. Impact on scantlings There is no impact on scantlings as the proposal is in line with intention of the Rules. PAGE 9 OF 36

169 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 8/ Background Corrugated bulkheads are generally utilised as the boundary between cargo tanks of small and medium sized product or chemical tankers. The corrugation provides benefits such as simplified cleaning which is highly desirable due to the operational profile of these vessel types. The last decade has seen significant innovation in the application of corrugated bulkheads to tanker design. In particular the use of corrugated bulkheads has extended to Aframax size and the size of tankers where corrugated bulkheads are fitted without bulkhead stools has also increased. The complexity of structural configuration and difficulties of manufacture can lead to significant defects occurring which may be costly to repair. Particularly for the connection of corrugated bulkheads at the inner bottom or hopper plating the special consideration need to be given to the use of special material with specified through thickness properties considering the potential lamellar tearing problem. Lamellar tearing can be caused by strain in the through-thickness direction that arises from the shrinkage of the weld metal as it cools. It is generally increased where free movement is restrained, as is the case for the connection between corrugated bulkheads and inner bottom plates. The heavier the weld, the greater is the susceptibility to lamellar tearing. Lamellar tearing will normally occur at the new building stage, but it can not be detected fully until the defects have propagated to the surface due to imposed stress during welding in production stage or operation with actual cargo loads. 2. Impact on scantlings There is no impact on scantlings as the proposal is mandating the use of Z-quality steel in areas with high strains in the thickness direction. PAGE 10 OF 36

170 TECHNICAL BACKGROUND COMMON STRUCTURAL RULES FOR RULE CHANGE NOTICE 1 FOR DOUBLE HULL OIL TANKERS, JULY 2010 Section 8/Table Background Table provides requirements for bulkheads with no lower stool. For bulkheads with no lower stool further investigations and service feedback highlighted that the coefficients for the bending moment distribution are not satisfactory. An investigation was carried out covering: Bending moments based on prescriptive requirements were compared with BM calculated from FE results for 3 different bulkheads Maximum S+D FE condition (A4-5A) was compared with prescriptive requirements applicable for S+D pressures FE results for L/Bhd. 1 and T/Bhd. 2 are based on actual project with variable thickness along the height (see figure below) FE results for L/Bhd. 3 are based on actual project with constant thickness along the height Three vertically corrugated bulkheads without stool tanks have been considered, one transverse bulkhead with variable thickness, and two longitudinal bulkheads. One of the longitudinal bulkheads has variable thickness and one has constant thickness over the height. There is significant disagreement between bending moment distribution obtained from the current prescriptive requirements versus values calculated by FE analysis, especially at the ends. The proposed update and a simple beam expression give good fit with the cases with variable thickness, but for the case with constant thickness these expressions over predict the bending moment at lower end (30%) and under predicts the bending moment at midspan (-12%). Three cases or vertically corrugated bulkheads are applied, of which this comparison covers type C: A) Bulkheads with upper stool and lower stool B) Bulkheads with lower stool only C) Bulkheads without stool The proposed updated bending moment coefficients gives good fit for bulkheads of type C with variable thickness. PAGE 11 OF 36