BULK CARRIER SAFETY. Formal Safety Assessment. Fore-end watertight integrity. Submitted by IACS SUMMARY

1 MARITIME SAFETY COMMITTEE 74th session Agenda Item 5 MSC 74/5/X February XXth, 2001 Original: ENGLISH BULK CARRIER SAFETY Formal Safety Assessment Fore-end watertight integrity Submitted by IACS SUMMARY Executive summary: This paper presents the FSA of bulk carriers, Fore-end watertight integrity, carried out by IACS 1. The focus of the study has been on the fore end of the bulk carriers, including the evaluation of risk control options aimed at preventing or mitigating fore end flooding scenarios. The scenarios investigated include the flooding of No. 1 cargo hold. Actions to be taken: Paragraph 4 Related documents: MSC/Circ.829, MSC 70/23 paragraph 4.28, MSC 71/23 paragraph 4.4, MSC 70/4/2 paragraphs 16 to 18, MSC 70/4/Add.1 and MSC 70/INF.14, MSC 72/16 1 Serious concerns have been expressed about the safety of bulk carriers for some time particularly following a spate of losses in the early 1990s. The IMO took several initiatives culminating in the 1997 SOLAS Conference on Bulk Carrier Safety. Revised rules and standards relating to the design and operation of bulk carriers were included in a new Chapter XII to the 1974 International Convention for the Safety of Life at Sea (SOLAS 74). IACS contributed to the development and implementation of the Enhanced Survey Programme (ESP) and the following IACS Unified Requirements (URs) were implemented: S12, Side structures in single side skin bulk carriers (IACS, 2000a) S17, Longitudinal strength of hull girder in flooded condition for bulk carriers (IACS, 2000b) S18, Evaluation of scantlings of corrugated transverse watertight bulkheads in bulk carriers considering hold flooding (IACS, 2000c) 1 The study was partly funded by UK Department of the Environment, Transport and Regions, as per letter dated 17 August 2000.

2 S19, Evaluation of scantlings of the transverse watertight corrugated bulkhead between cargo holds Nos. 1 and 2, with cargo hold No. 1 flooded, for existing bulk carriers (IACS, 2000d) S20, Evaluation of allowable hold loading for bulk carriers considering hold flooding (IACS, 2000e) S21, Evaluation of scantlings of hatch covers of bulk carrier cargo holds (IACS, 1997) S22, Evaluation of allowable hold flooding of cargo hold No. 1 with cargo hold No. 1 flooded, for existing bulk carriers (IACS, 2000f) S23, Implementation of IACS Unified Requirements S19 and S22 for existing single side skin bulk carriers (IACS, 1998a) S24, Detection of water ingress into cargo holds of existing bulk carriers (IACS, 1998b) 2 The objective of the present submission is to provide the results of a FSA study for the fore end watertight integrity that can support IMO and IACS decisions relating to the development of additional appropriate international rules and standards to further enhance the safe operation of bulk carriers. 3 The scope of the study with respect to the FSA Steps 1 to 5 conducted in accordance with FSA Interim Guidelines was to:.1 Review previously conducted hazard identification studies (MSC 72/INF.4) and other relevant information gathered from the FSA study co-ordinated by UK MCA (2000). Define generic bulk carriers. Collect and analyse (on an overall level) relevant data from different sources and organisations. Collect casualty data for bulk carriers on a broad basis, not limited to the watertight integrity of the fore end. (FSA Step 1).2 Analyse in detail the risks related to loss of watertight integrity of the forepeak and the first cargo hold, due to side shell failure, failure of hatches and ventilators, and hatch cover failures by analysing frequencies of failure and consequences. (FSA Step 2).3 Identify risk control options, by reviewing earlier submissions to the IMO, like the Derbyshire investigation report, and the latest international rules and standards related to structural design of bulk carriers. (FSA Step 3).4 Perform cost effectiveness analysis of the selected risk control options (FSA Step 4).5 Prepare documentation to serve as a basis for decision making (FSA Step 5) 4 The risk control options considered are listed below. Already implemented risk control options: 1. SOLAS Ch. XII (including IACS UR, e.g. strength of bulkheads included) and strengthening of bulkheads on existing bulk carriers 2. The Enhanced Survey Programme (ESP) 3. Hatch cover strength of IACS UR S21

3 New risk control options: 1. Forecastle or bulwark 2. Strengthening of bulkheads 3. Strengthening of hatch covers and user friendly systems for hatch cover closure 4. Reduced loading/increased freeboard 5. Water ingress alarm in cargo holds and the forepeak. 6. Revised design standard for deck openings 7. Double side skin structures 8. Application and maintenance of coating of internal single side skin structure of cargo holds 5 The FSA report is included in the Annex. Background information is available at the IACS website www.iacs.org.uk. 6 IACS is currently assessing the findings of this FSA study, with the view to recommending appropriate actions. Actions requested of the Committee 7 The Committee is invited to review the recommendations and documentation of the present FSA study and, in general, to note the progress made by IACS on this subject.

1 ANNEX Bulk Carrier Safety Fore End Watertight Integrity 1 SUMMARY 1.1 Executive summary This paper presents the FSA study on Bulk Carriers Fore End Watertight Integrity carried out by IACS. The focus of the study was on the fore end of bulk carriers, including No. 1 cargo hold. The present FSA report follows the standard reporting format for FSA studies, as defined in MSC/Circ.829. The objective of the present study was to provide documentation that can support IMO and IACS decisions relating to the development of additional appropriate international rules and standards to further enhance the safe operation of bulk carriers. An overall risk assessment was performed, and focus for the risk control options was given to fore end water ingress scenarios related to: Side shell failure of No. 1 cargo hold Failure of deck fittings No. 1 hatch cover failure Different methodologies were utilised in the study depending on the scenario and the risk control options investigated, and the casualty data available for each scenario. In order to establish the present base risk, the following already implemented risk control options were assessed: 1. SOLAS Ch. XII (including IACS UR, e.g. strength of bulkheads included) and strengthening of bulkheads on existing bulk carriers 2. The Enhanced Survey Programme (ESP) 3. Hatch cover strength of IACS UR S21 All of the implemented risk control options were found to imply implicit Willingness To Pay within the recommended decision criterion of MSC 72/16 (US$ 3 million per fatality averted). Following their implementation, the Potential Loss of Life (i.e., the average number of fatalities per ship year) was estimated reduced by 26% for existing bulk carriers of 150m or more and 67% for new-buildings. The further risk control options evaluated were: 1. Forecastle or bulwark 2. Strengthening of bulkheads 3. Strengthening of hatch covers and user friendly systems for hatch cover closure 4. Reduced loading/increased freeboard 5. Water ingress alarm in cargo holds and the forepeak. 6. Revised design standards for deck openings 7. Double side skin structures

2 8. Application and maintenance of coating of internal single side skin structure of cargo holds Based on the results from the present study, the risk control options referred below will be subject for further consideration by IACS. Risk control options for existing bulk carriers of more than 150 m: Deck fittings (develop and apply new standards). Bulwark or forecastle on bulk carriers shorter than 230 m. Water ingress alarm in the forepeak and all cargo holds. Speeding up the implementation of SOLAS Chapter XII. Replacing hatch covers on existing bulk carriers with hatch covers in accordance with IACS Unified Requirement S21 has been found not giving firm conclusions about its need of implementation as a RCO. Hence, hatch cover risk control options are recommended to be subject to further evaluation. Risk control options for bulk carrier new-buildings of more than 150 m: Deck fittings (develop and apply new standards). Water ingress alarm (all ships, all cargo holds and forepeak). Forecastle or bulwark for panamax and smaller bulk carriers. Double side skin. Although out of scope of the present study, a brief review of casualty data for smaller bulk carriers was conducted. Based on the review, it cannot be concluded that smaller bulk carriers are less at risk than the larger ones. Hence, IACS will consider performing a more thorough evaluation of smaller bulk carriers and relevant risk control options. Some of the risk control options evaluated for larger bulk carriers are assessed as promising also for smaller ships: Deck fittings (develop and apply new standards). Bulwark or forecastle. Double side skin. Water ingress alarm in all cargo holds and the forepeak. 1.2 Related documents MSC/Circ.829, MSC 70/23 paragraph 4.28, MSC 71/23 paragraph 4.4, MSC 70/4/2 paragraphs 16 to 18, MSC 70/4/Add.1 and MSC 70/INF.14, MSC 72/16, MSC 72/INF.4, MSC 73/INF.10, MSC 72/4/1/Add. 1, MSC 70/4, MSC 70/4/6, MSC 72/4/1, MSC 72/4/1/Add. 1, MSC 72/16, MSC72/INF.7. 2 DEFINITION OF THE PROBLEM 2.1 Definition of the problem The objective of the present study was to provide documentation that can support IMO and IACS decisions relating to the development of additional appropriate international rules and standards to further enhance the safe operation of bulk carriers.

3 2.2 Reference to the regulation(s) affected by the proposal to be reviewed or developed The regulations affected by the recommendations from the present study are currently under consideration. 2.3 Definition of the generic model The bulk carriers considered are ships constructed with topside tanks and hopper side tanks in cargo spaces, intended primarily to carry dry cargo in bulk. This definition is in accordance with the definition as given in SOLAS Chapter IX, Regulation 1. A bulk carrier classification, including the bulk carrier length, which is deemed to be an important parameter in a regulatory context, was adopted as shown in Table 1. In this study, the bulk carrier characterisation is based on DWT. Table 1 Classification of Bulk Carrier in size (MSC74/Inf.x submitted by Japan) Bulk carrier L f (m) GT DWT (ton) (Mini) 100-130 Small-Handy 130-150 5K-14K 10K-23K Handymax 150-200 14K-30K 23K-55K Panamax 200-230 30K-45K 55K-80K Capesize 230-270 (VL) 270+ 45+ K 80+ K Three typical bulk carrier sizes were considered. The main characteristics of the selected ships are listed in Table 2. Table 2 Bulk carriers used in the study Ship Moulded Deadweight Summer freeboard Capacity of forepeak (m 3 ) dimensions (m) (tonnes) (m) Handymax 181 x 30 x 16.3 51,326 4.718 1,450 Panamax 217 x 32.25 x 19 83,980 5.250 1,555 Capesize 271 x 45 x 24.6 188,968 6.483 4,507 The selected ships were constructed before the entry into force of the new SOLAS Chapter XII with flush deck and B-60 freeboard. The bulk carriers were assumed to be sailing 150 days per year in loaded condition. 3 BACKGROUND INFORMATION 3.1 Recently introduced risk control options Over the past 10 years, several risk control options have been implemented for bulk carriers:

4 the Enhanced Survey Programme (ESP) (IACS, 1999) IACS UR S21 (IACS, 1997) SOLAS chapter XII applicable to bulk carriers over 150 m (IMO, 2000) The influences of the different implemented risk control options are schematically shown in the fault and event trees below. Substantial water ingress in forepeak or No. 1 cargo hold OR Escalation? YES NO Influenced by SOLAS Chapter XII Total loss of ship Serious casualty Side shell failure Hatch cover failure Failure of deck fittings Influenced by ESP Influenced by IACS UR S21 Figure 1 Simple risk model showing the influence of the ESP, IACS UR S21, and SOLAS Chapter XII. In the sections below, the effectiveness of each of these risk control options is discussed. The estimates given refer to the terms Gross Cost of Averting a Fatality (Gross CAF) and Net Cost of Averting a Fatality (Net CAF). Their definitions are: C GrossCAF = R C B NetCAF = R where C B is the cost per ship of the risk control option, is the economic benefit per ship resulting from the implementation of the risk control option and R is the risk reduction per ship, in terms of number of fatalities averted, implied by the risk control option.

5 3.1.1 The Enhanced Survey Programme (ESP) The Enhanced Survey Programme (ESP) was implemented as an IACS Unified Requirement on 1 July 1993 (IACS, 1999). The average overall cost due to ESP was estimated to app. US$ 66,000 per bulk carrier, whereas the risk reduction due to ESP was estimated based on historical casualty data. This risk reduction may include effects from other implemented measures, like the ISM code, but due to lack of detailed information, the entire risk reduction was attributed to ESP. ESP may prevent side shell failure and hence side shell failure casualties. The number of serious casualties due to side shell failure was found to have declined by app. 19% following the introduction of ESP, see Annex 2, corresponding to app. 0.0022 fatalities averted per ship year, and 0.055 fatalities averted per ship lifetime of 25 years. This gave a Gross Cost of Averting a (statistical) Fatality (CAF) of US$1.2 million, which is a measure of the Willingness To Pay implied by the decision to implement the ESP. 3.1.2 IACS UR S21 IACS UR S21 was implemented in July 1998 (IACS, 1997), giving stricter requirements for the design of hatch covers, compared to the International Load Line Convention of 1966 (ILLC 66). Based on structural reliability analyses and estimates based on casualty statistics, IACS UR S21 was estimated to reduce the annual probability of No. 1 hatch cover collapse by between 90 and 99% compared to ILLC 66. The hatch cover collapse failure mode was estimated to account for 70% of serious casualties related to hatch covers. The estimated probability of failure for a capesize No. 1 hatch cover is presented in the table below. For details, see Annex 4. Table 3 Annual probability of hatch cover failure Case Probability of hatch cover collapse, estimated by structural reliability analysis Probability of hatch cover collapse, estimated from casualty data Initial design, 9.35 10-4 2.9 10-4 - 1.4 10-3 ILLC 66 UR S21 1.16 10-5 - The marginal cost effectiveness of UR S21 at the time of its implementation was estimated to US$ 1.54 million, which is close to the recommended decision criterion of MSC72/16. Since the implementation of IACS UR S21, SOLAS XII has also been implemented. SOLAS XII is partly aiming at mitigating consequences given flooding of cargo holds. For the future, this will probably reduce the probability of escalation given flooding of No. 1 cargo hold. When evaluating a further increase in the design loads of IACS UR S21, this effect should be taken into account. UR S21 is presently under consideration for amendment in the light of the recommendations from the Derbyshire hearing.

6 3.1.3 SOLAS Chapter XII The SOLAS Chapter XII contains several Risk Control Measures. Cost effectiveness analysis was carried out for the risk control options applying to bulkhead capacity for new-buildings and existing bulk carriers, see Table 4. Table 4 shows the results for the two risk control options evaluated. The estimated effect of ESP was accounted for in the analysis. For details, see Annex 3. Table 4 Summary of Cost Effectiveness Analyses RCO No. RCO1 RCO2 RCO description Requirements of structural strength at flooding condition and damage stability for new bulk carrier (Regulation 4 and 5 in SOLAS Chapter XII for new bulk carrier) Requirements of structural strength at flooding condition and damage stability for existing bulk carrier (Regulation 4 and 6 in SOLAS Chapter XII for existing bulk carrier) RCO costs, D C (US$) Risk reduction, D R, (fatalities averted) Gross CAF (US$ million per fatality averted) 77,000 144,000 1.47E-01 0.5.10 108,000 138,000 4.54E-02 2.4 3.0 3.1.4 Residual risk considerations Details are given in Annex 2. The risk model as shown in Figure 1 above was used to estimate the residual risk after the implementation of ESP, IACS UR S21 and SOLAS Chapter XII. For existing bulk carriers, the combined effect of ESP and SOLAS Chapter XII was estimated to reduce the number of fatalities per ship year due to structural failure by approximately 26%, compared to the casualties in the period from 1978 to 1998. This corresponds to a reduction of 20% in the total PLL for bulk carriers. For new-buildings, ESP, IACS UR S21, and SOLAS Chapter XII was estimated to reduce the expected number of fatalities per ship year due to structural failure by approximately 67%. This corresponds to a reduction of 50% in the total Potential Loss of Life (PLL) for bulk carriers. The PLL is defined as the mean number of fatalities per ship year. Since the major part of structural failure related casualties occurs to the older part of the bulk carrier fleet, this means that it may take some time before the new-building modifications will affect the casualty statistics significantly. 3.2 Casualty statistics concerning the problem under consideration This section reports the main findings from the analysis of bulk carrier casualty data. The details are found in Annex 2. The casualty database of Lloyd s Maritime Information Services (LMIS, 1999, 2000) was used to establish a base risk level for bulk carriers. Where necessary, the information given was supplemented by Lloyd's Casualty Reports (LCR). Data from 1978 to 1998 was analysed. The

7 casualty data used contained a small number of double side skin bulk carriers. Fleet data in the period 1978-98 were estimated based on Lloyd's Statistical Tables (1978 to 1998). The data represents 73,600 ship years for bulk carriers larger than 20,000 DWT. In the investigation, other data sources such as internal class survey reports and databases were referred if necessary and when available, e.g. (Japan, 1981) and (Intercargo, 2000). Fleet risk results were reported in MSC 72/16. Individual risks for bulk carriers were found to be in the ALARP region, implying that cost effective risk control options should be implemented. Individual risk 1.00E-02 1.00E-03 1.00E-04 1.00E-05 1.00E-06 1.00E-07 Oil Tanker Chemical Tanker Oil/Chemical Tanker Intolerable Risk ALARP Negligible Risk Gas Tanker Bulk/Oil Carrier Bulk Carrier (incl. Ore) Container Vessel General Cargo Carrier Ro/Ro Cargo Carrier Figure 2 Individual risk of fatality to crew on different ship types (MSC 72/16) Figure 3 gives the contribution to the average number of fatalities per ship year from different accident categories, and different failure modes for structural failure. Structural failure casualties are taken as casualties in the LMIS casualty database being reported as Foundered, Missing, or Hull/Machinery Damage, with sub-coding Hull. Bulk carriers larger than 20,000 dwt PLL = 0.017 fatalities per ship year (excluding personal accidents) Fire/ Explosion 8.1% Collision 9.4% Contact 1.2% War/ hostilities 1.4% Foundering /missing/ hull damage 72.7% Wrecked/ stranded 0% Machinery damage 4.2% Other 3% Side shell failure 45.8% Hatch cover failure 18.7% Failure of deck fittings and ventilators 3.5% Other 4.7%

8 Figure 3 excluded). Risk distribution for the Potential Loss of Life (PLL), personal accidents The analysis of historical data revealed that casualties that may be attributed to structural failure, in the period from 1978 to 1998 accounted for approximately 73 % of all casualty related fatalities on bulk carriers larger than 20,000 DWT. The structural failures may be concluded to have been a major problem to bulk carrier safety, and it appears to be reasonable that this accident category was given focus in the present study. 3.3 Relevant limitations The present study is limited to handymax, panamax, and capesize bulk carriers, and focus was given to fore end water ingress related to the following scenarios: Side shell failure of No. 1 cargo hold Fore peak flooding from failure of deck fittings No. 1 hatch cover failure 4 METHOD OF WORK 4.1 Composition and level of expertise of those having carried out the trial application The core project team consisted of the following persons: Dr. Monika L Eknes (DNV) Dr. Toshiro Arima (ClassNK) Mr. Giovanni Guassardo (RINA) The core project team involved the required competencies as appropriate during the project, and Table 5 lists the roles of the personnel involved in the study. Names and credentials can be found in Annex 7. Table 5 Expertise involved in study DNV ClassNK RINA Structural reliability expert FSA expert FSA expert Environmental loads expert Hull damage investigation expert Hydrodynamic and Structural 2 Hydrodynamic analysis Hull structure and Rule development Reliability expert expert expert FSA expert 2 Hull structure and design experts Automation expert DNV brainstorming session Former bulk carrier captain and presently assisting QA manager 2 Experts within hull structures Experienced bulk carrier surveyor ClassNK brain storming session Ship designer Ship operator with good experience as a Master of Bulk Carriers Hull structure and Rule development expert Hull structure and plan approval expert with good experience as ship 2 Stability and Hydrodynamics experts 2 professional surveyors of hull and machinery 1 consultant in shipping construction 1 expert of onboard automation systems

9 SOLAS and load line expert Environmental loads expert International Safety Management Code (ISM) expert and former navy captain FSA expert designer Machinery expert with good experience as a Chief Engineer ISM expert with good experience as a Chief Officer of Bulk Carrier Material and Matter of IMO expert 4.2 Description on how the assessment has been conducted Figure 4 below gives a summary of the main tasks of the assessment. Each core project team member was responsible for a number of milestones and managed project teams of internal and external experts in order to meet the milestones. Project planning core project team meeting Review of HAZIDs and other relevant background documentation Risk Analysis Casualty data analysis finished Risk control option brainstorming sessions Project team meeting for selection of risk control options Cost effectiveness analysis of selected risk control options Draft version of report finished 1 December 2000 Updated version of report finished 16 January 2001 IACS review meeting 25 and 26 January 2001 Final report Figure 4 Main tasks of study 4.3 Start and finish date of the assessment. The assessment was initiated March 1, 2000 and finished February 15, 2001. 5 DESCRIPTION OF THE RESULTS ACHIEVED IN EACH STEP 5.1 STEP 1 HAZARD IDENTIFICATION 5.1.1 Hazard List from Literature A review of previously conducted Hazard Identifications (MSC 72/INF.4, MSC 72/INF.8, and UK MCA (2000)) was performed in order to identify relevant hazards, principal causes, and effects. The full list of hazards is given in Annex 8.

10 The actual basic hazard analysed in this study was the Loss of watertight integrity of the fore-end, including hold No.1, due to internal causes (i.e., excluding events such as collision, grounding etc.). Therefore, only the accident scenarios related to the Loss of watertight integrity of the fore-end were investigated. From the relevant historical data, the following most significant accident scenarios were identified: 1. side-shell failure 2. forepeak flooding from the deck fittings 3. hatch cover failure. In this perspective, the hazards as defined in the reviewed HAZIDs can be more properly viewed as possible causes and/or aggravating factors of the above scenarios. 5.2 STEP 2 RISK ASSESSMENT 5.2.1 Risk model and approach The scenarios addressed in this study are characterised by the following events, see Figure 5: 1. Water ingress due to side shell failure, hatch cover failure, or failure of deck fittings. 2. In some of the cases there are progressive flooding of cargo holds, leading to total loss of ship and also often fatalities. The progressive flooding may be due to collapse of bulkheads, hull girder collapse, cargo liquefaction, hatch cover collapse or side shell failure. 3. In the remaining cases, the flooding is limited, resulting in serious casualty and not total loss, and few, if any, fatalities. Substantial water ingress in forepeak or No. 1 cargo hold Escalation? YES NO Total loss of ship Serious casualty OR Side shell failure Hatch cover failure Failure of deck fittings Figure 5 Scenarios under consideration Below, flooding scenarios due to side shell failure, hatch cover failure, and failure of deck fittings are assessed, together with water ingress scenarios in general. The scenarios are assessed in terms of their contribution to the Potential Loss of Life (PLL) and Economic Losses (EL), estimated from casualty data according to: PLL = scenario Number of fatalities related to scenario Correspond ing number of ship years

11 EL scenario Number of total losses = Cost of total loss Correspond ing number of ship years Number of serious casualties + Cost of serious casualty Correspond ing number of ship years Table 9 in Annex 2 gives a loss matrix for generic bulk carrier accidents. Here, a generic serious casualty is estimated to cost US$ 5,608,000 and a total loss US$ 24,808,000, including costs of total loss, damage repair, lost cargo, salvage, and clean-up. 5.2.2 Water ingress accident scenarios, 1978-1998 Reference is given to Annex 2. In the LMIS casualty database, casualties involving water ingress were identified. In addition to checking by the coding of each scenario, free texts were reviewed in order to assign the casualties to the three scenarios under investigation. The table below summarises the number of casualties identified. Table 6 Number of serious casualties, total losses, and fatalities, 1978-1998 Scenario Number of serious casualties, exc. total losses Number of total losses Number of fatalities General water ingress scenarios 115 72 850 Flooding due to side shell failure 98 62 572 Forepeak flooding due to failure of 7 3 44 deck fittings Flooding due to hatch cover failure 11 9 246 The risk contribution from the water ingress scenarios in terms of PLL and estimated economic losses is given in the table below. Table 7 Risk contributions from water ingress scenarios for bulk carriers 1978 to 1998 Scenario PLL contribution (fatalities per ship year) Economic losses (US$ per ship year) General water ingress scenarios 1.15 10-2 33,000 Flooding due to side shell failure 7.8 10-3 28,400 Forepeak flooding due to failure of 5.98 10-4 1,500 deck fittings Flooding due to hatch cover failure 3.34 10-3 3,900 The estimates given above are encumbered with statistical uncertainty. Even though the risk contribution from the water ingress scenarios in general is a significant estimate, the break down on the underlying scenarios is more uncertain, e.g. the importance of the side shell failure scenarios may be over-estimated, whereas the importance of the hatch cover failure scenarios may be underestimated.

12 A detailed break down of the casualty data was performed, in order to assess the risks from side shell failure and hatch cover failure related to the fore end. The fore end was found to contribute with app. 50% of the fatalities due to side shell failure, whereas failure of the No. hatch cover was found to related to 244 out of the 246 hatch cover failure related fatalities, i.e. 99%. 5.2.3 Present risks from water ingress scenarios In order to estimate the present risks from the water ingress scenarios considered, the effect of recently implemented risk control options were taken into account for new and existing bulk carriers. The results are given in the tables below, and details are found in Annex 2. Table 8 Loss matrix for bulk carrier (US$/generic accident) Cost item Serious casualties (excluding total losses) Total losses Cost of total loss 16,900,000 Cost of damage repair 2,600,000 Cost of lost cargo 2,500,000 7,400,000 Cost of salvage 130,000 130,000 Total damage costs 5,230,000 24,430,000 Clean-up costs 378,000 378,000 Overall costs (exc. fatalities) 5,608,000 24,808,000 5.3 STEP 3 RISK CONTROL OPTIONS The selected risk control options explored were: Forecastle or bulwark (new and existing ships) Further risk control options for strengthening of bulkheads Hatch cover strength and user friendly systems for hatch cover closure Reduced loading/increased freeboard Water ingress alarm in cargo holds and the forepeak. Design standard for deck openings Double side skin structure Coating of internal single side skin structure of cargo holds and requirement for maintenance The full details are given in Annex 9 and 10. 5.4 STEP 4 COST BENEFIT ASSESSMENT 5.4.1 Approach Each participating organisation evaluated one or two of the water ingress scenarios together with the risk control options relevant to that scenario, see Figure 6. Different methodologies were utilised in the study depending on the scenario and the risk control options investigated, and the casualty data available for each scenario.

13 For water ingress scenarios in general, and side shell failure scenarios, the extent of casualty data in general was sufficient to be used to evaluate the effect of the risk control options directly. Hence, the approach adopted implied evaluating the casualties one by one to assess whether it could have been prevented or mitigated by the risk control options studied. Details are given in Annex 4. For the flooding scenarios due to hatch cover failure, casualty data was scarce. The risk control options studied in general was aimed at enhancing the structural strength of hatch covers. Hence, structural reliability analysis was utilised to predict the differences in annual probabilities of hatch cover failure for different designs. Details are given in Annex 4. For the flooding scenarios involving flooding of the forepeak, casualty data was also scarce. An event tree was established, with nodes reflecting the risk control options studied. The probabilities of the different nodes were quantified by using simplified physical models. Details are given in Annex 5. Risk control options evaluated: SOLAS Ch. XII Reduced loading/increased freeboard Water ingress alarm in cargo holds and the forepeak. Substantial water ingress in forepeak or No. 1 cargo hold OR Escalation? YES NO Total loss of ship Serious casualty Side shell failure Hatch cover failure Failure of deck fittings Risk control options evaluated: Forecastle or bulwark Water ingress alarm in the forepeak. Design standard for deck openings Risk control options evaluated: ESP Double side skin structure Coating of internal single side skin structure including maintenance Risk control options evaluated: Hatch cover strength and user friendly systems for hatch cover closure, including URS21 Figure 6 Risk control options studied in relation with the different scenarios 5.4.2 Water ingress scenarios in general Related to water ingress scenarios in genera, the cost effectiveness of the evaluated risk control options is given in the table below. Table 9 Summary of CEA for risk control options related to water ingress scenarios in general

14 RCO description D C (US$) D R (fatalities averted ship) per Gross CAF (US$ million) Net CAF (US$ million) Strengthening all bulk heads for 455,000-635,000 9.24E-02 4.9-6.9 4.5-6.4 existing bulk carrier Speeding up the implementation of SOLAS Chapter XII. IACS will 108,000-138,000 5.91E-02 1.8-2.3 1.3-1.8 consider using 10 years as threshold in stead of 15 years. Increased freeboard on capesize bulk carriers with hatch covers designed according to ILLC 66 0.5 m 227,000 < 8.50E-03 > 27 > 24 1.5 m 680,000 < 8.50E-03 > 80 > 77 Coating of internal side skin structure New-building 175,000 9.50E-02 1.8 0.4 10 year old ship 175,000 7.35E-02 2.4 0.3 15 year old ship 175,000 4.90E-02 3.6 1.0 20 year old ship 175,000 2.45E-02 7.1 4.0 Water ingress alarm in all cargo holds and forepeak New-building 7,500-27,000 2.15E-02 0.4-1.3 0.4-1.3 10 year old ships 25,000-90,000 2.85E-02 0.9-3.2 0.9-3.2 15 year old ships 25,000-90,000 1.90E-02 1.3-4.7 1.3-4.7 20 year old ships 25,000-90,000 9.50E-03 2.6-9.5 2.6-9.5 Double side skin in all cargo holds New-building, 131,000-182,000 1.60E-01 0.8-1.1 0.1-0.4 10 year old ships 623,000-1,196,000 1.46E-01 4.3-8.2 3.6-7.6 15 year old ships 623,000-1,005,000 1.00E-01 6.2-10.0 5.5 9.4 Double side skin in No.1 and No.2 holds, 10 year old ships Capesize 416,000 630,000 2.41E-01 1.7 2.6 1.4 2.3 Panamax 250,000 545,000 6.53E-02 3.8 8.4 2.6 7.2 Handymax 220,000-406,000 4.75E-02 4.6 8.6 3.0 6.9 Double side skin in No.1 and No.2 hold, 15 year old ships Capesize 416,000-559,000 2.29E-01 1.8 2.4 1.6 2.2 Panamax 250,000-450,000 3.87E-02 6.5 12.0 4.9 10.0 Handymax 220,000-344,000 3.75E-02 5.9 9.2 4.3 7.6 5.4.3 Forepeak flooding due to failure of deck fittings The table below summarises the results for the risk control options related to the fore end flooding accident scenarios. Table 10 Summary of CEA of risk control options related to fore end flooding RCO description Forecastle, new-building D C (US$) D R (fatalities averted per ship) Gross CAF (US$ million) Net CAF (US$ million)

15 Capesize 54,000-102,000 2.11E-02 2.6 4.8 2.2 4.5 Panamax 29,100-54,000 4.93E-02 0.6 1.1 0.2 0.7 Handymax 15,600-30,000 9.33E-02 0.2 0.3-4.9-2.0 Forecastle, 15 year old ship Capesize 180,000-340,000 8.45E-03 21-40 20 39 Panamax 97,000-180,000 1.97E-02 4.9-9.2 4.3 8.5 Handymax 52,000-100,000 3.73E-02 1.4-2.7 0.8 2.1 Bulwark, new-building Capesize 24,000-45,000 2.11E-02 1.1 2.1 0.8 1.8 Panamax 13,500-25,200 4.93E-02 0.3-0.5-0.1* 0.2 Handymax 7,800-14,100 9.33E-02 0.10-0.2-0.3* -0.2* Bulwark, 15 year old ship Capesize 80,000-150,000 8.45E-03 9.5-18 8.8 17 Panamax 45,000-84,000 1.97E-02 2.3-4.2 1.7-3.7 Handymax 26,000-47,000 3.73E-02 0.7-1.3 0.1 0.6 Monitoring system for detecting water ingress in forepeak, new building Capesize 13,200-19,000 1.85E-02 0.7-0.9 0.2 0.4 Panamax 13,200-19,000 2.38E-02 0.5-0.7-0.6* -0.4* Handymax 13,200-19,000 1.30E-01 0.1-0.13-0.3* -0.2* Monitoring system for detecting water ingress in forepeak, 15 year old ships Capesize 40,000-57,000 7.40E-03 5.4 7.7 4.6 6.9 Panamax 40,000-57,000 9.50E-03 4.2 6.0 2.4 4.2 Handymax 40,000-57,000 5.20E-02 0.8 1.1 0.2 0.5 * The negative Net CAFs are caused by the economic benefits from the risk control option exceeding the costs of the risk control option. 5.4.4 Flooding due to hatch cover failure Table 11 below summarises the Gross CAFs for the hatch cover risk control options evaluated. Table 11 Summary of CEA of risk control options related to hatch cover failure RCO description D C (US$) D R (fatalities averted per ship) Gross CAF (US$ million) Net CAF (US$ million) IACS UR S21 hatch covers to replace ILLC 66 hatch covers on existing capesize carriers 10 year old ships 105,000 175,000 5.16E-02-1.71E-01 0.6-3.4 0.1-3.2 15 year old ships 105,000 175,000 3.44E-02-1.14E-01 0.9-5.1 0.3-4.9 20 year old ships 105,000 175,000 1.72E-02-5.71E-02 1.8 10.2 1.0-9.9 Hatch covers designed to a 30% increase in IACS UR S21 design loads to replace IACS UR S21 hatch covers on existing ships. 10 year old ships 120,000-200,000 2.00E-03 60 100 60-100 15 year old ships 120,000-200,000 1.34E-03 90 150 90 150 20 year old ships 120,000-200,000 6.68E-04 180 300 180-300

16 Hydraulic hatch cover closure system on No. 1 hatch cover 10 year old ships 58,000 1.95E-02 3.0 2.4 15 year old ships 58,000 1.30E-02 4.5 3.8 20 year old ships 58,000 6.49E-03 8.9 8.1 New-buildings 58,000 1.46E-02 4.0 3.4 30% increase in IACS UR S21 design loads for new ships - - 86 5.5 STEP 5 - RECOMMENDATIONS FOR DECISION-MAKING The risk control options, ranked in terms of cost effectiveness, are listed below. Negative Net CAF: 1. Monitoring system for detecting water ingress in forepeak for Panamax and Handymax new-buildings 2. Bulwark on Panamax and Handymax new-buildings 3. Forecastle on Handymax new-buildings The negative Net CAFs are due to the economic benefits exceeding the costs of the above risk control options, which therefore seem to be justifiable from a commercial viewpoint alone. Gross CAF below US$ 1 million: 1. Double side skin in all cargo holds for all bulk carrier new buildings (as an alternative to SOLAS XII) 2. Water ingress alarm for all bulk carrier new-buildings 3. Bulwark for Panamax and smaller bulk carrier new-buildings 4. Fore castle for Handymax and smaller bulk carriers new-buildings 5. Monitoring system for detecting water ingress in forepeak for Panamax and smaller bulk carrier new-buildings Gross CAF between US$ 1 and 3 million: 1. Bulwark for handymax and smaller existing bulk carriers 2. Bulwark for Capesize new buildings 3. Water ingress alarm for existing bulk carriers up to 15 years 4. Monitoring system for detecting water ingress in forepeak for Handymax and smaller existing bulk carriers 5. Speeding up the implementation of SOLAS Chapter XII. IACS will consider using 10 years as threshold in stead of 15 years. 6. Double side skin in No.1 and No.2 cargo holds for 10 year old Capesize bulk carrier (as an alternative of SOLAS XII) 7. Double side skin in No.1 and No.2 cargo holds for 15 year old Capesize bulk carrier (as an alternative of SOLAS XII) 8. Coating of internal single side skin structure on new-buildings and 10 year old bulk carriers Gross CAF between US$ 3 and 10 million:

17 1. Water ingress alarm for 20 year old bulk carriers 2. Coating of internal single side skin structure on 15 and 20 year old bulk carriers 3. Monitoring system for detecting water ingress in forepeak for existing Capesize and Panamax carriers 4. Bulwark or forecastle for existing Panamax bulk carriers 5. Forecastle for Capesize bulk carriers new buildings 6. Hydraulic hatch cover closure system on No. 1 hatch cover for new and existing ships 7. Strengthening all bulk heads for existing bulk carrier (as further enhanced requirements to existing bulk carriers; applying same requirements to existing bulk carrier as required to new bulk carrier in Regulation 4 and 5 in SOLAS Chapter XII for new bulk carrier ) 8. Double side skin in all cargo holds for 10 and 15 year old bulk carriers 9. Double side skin in No.1 and No.2 cargo holds for 10 year old Panamax and Handymax bulk carrier 10. Double side skin in No.1 and No.2 cargo holds for 15 year old Handymax bulk carrier 11. Monitoring system for detecting water ingress in forepeak for existing Panamax and Capesize bulk carriers Gross CAF higher than US$ 10 million: 1. 30% increase in IACS UR S21 design loads for new ships 2. Hatch covers designed to a 30% increase in IACS UR S21 design loads to replace IACS UR S21 hatch covers on existing ships 3. Increased freeboard by 0.5 or 1.5 m on capesize bulk carriers with hatch covers designed according to ILLC 66 4. Bulwark or forecastle for existing Capesize bulk carriers 5. Double side skin in No.1 and No.2 cargo holds for 15 year old Panamax bulk carrier 6. Monitoring system for detecting water ingress in forepeak for existing Capesize carriers 6 FINAL RECOMMENDATIONS FOR DECISION MAKING The risk control options referred below will be subject to further consideration by IACS. 6.1 Risk control options for existing ships longer than 150 m Risk control options, which will be considered by IACS, for existing bulk carriers longer than 150 m: Deck fittings: consider conducting a research study on retroactive application of new strength and/or isolation standard for deck fittings. Bulwark or forecastle on bulk carriers shorter than 230 m: consider fitting existing bulk carriers with bulwark or forecastle and compare their effect and costs to improved deck fittings. Water ingress alarm: consider requiring water ingress alarm, giving continuous reading of the water level in any cargo hold or the forepeak. Speeding up the implementation of SOLAS Chapter XII: consider using 10 years as threshold in stead of 15 years. Replacing hatch covers on existing bulk carriers with hatch covers in accordance with IACS Unified

18 Requirement S21 has been found to have Gross CAFs not giving firm conclusions about implementation. Hence, hatch cover risk control options are recommended to be subject for further evaluation. Alternative risk control options here could be to replace only hatch cover No. 1. The variation between different hatch cover designs in terms of actual strength may be large, hence a screening of the fleet in order to identify the ships most at risk and the individual cases where the replacement of hatch covers is a cost effective risk control option. 6.2 Risk control options for new-buildings Risk control options, which will be considered by IACS, for bulk carrier new-buildings longer than 150 m: Deck fittings (develop and apply new standards) Water ingress alarm (all ships, all cargo holds and forepeak) Forecastle or bulwark for panamax and smaller Double side skin 6.3 Risk control options for existing ships and new-building less than 150 m Although out of scope of the present study, a brief review of casualty data for smaller bulk carriers was conducted, and it could, based on the review, not be concluded that smaller bulk carriers are less at risk than the larger ones. Hence, IACS will consider performing a more thorough evaluation of smaller bulk carriers and relevant risk control options. Some of the risk control options evaluated for larger bulk carriers are assessed as promising also for the smaller ships: Deck fittings Bulwark or forecastle Double side skin Water ingress alarm in all cargo holds and the forepeak

19 7 REFERENCES Annex 1 Annex 2 Annex 3 Annex 4 Annex 5 Annex 6 Annex 7 Annex 8 Annex 9 Annex 10 Definitions and Abbreviations, www.iacs.org.uk Risk for Bulk Carriers, www.iacs.org.uk General Water Ingress Scenarios, www.iacs.org.uk Hatch Cover Failure Scenarios, www.iacs.org.uk Fore-end Flooding Scenarios, www.iacs.org.uk Casualty Lists, www.iacs.org.uk Names and Credentials, www.iacs.org.uk Hazard Identification of Fore-end of Bulk Carriers, www.iacs.org.uk Risk Control Options from Literature), www.iacs.org.uk Risk Control Options Identified in Brainstorming Sessions, www.iacs.org.uk DETR (1998), M.V. Derbyshire Surveys, UK/EC Assessors Report, A summary, Department of the Environment, Transport and the Regions, UK, March 1998. IACS (1997), Evaluation of Scantlings of Hatch Covers of Bulk Carrier Cargo Holds. IACS Requirements 1997, Volume 1, S21. IACS (1998a), Implementation of IACS Unified Requirements S19 and S22 for existing side skin bulk carriers. IACS Requirements 1998, S23, Rev. 2.1. IACS (1998b), Detection of water ingress into cargo holds of existing bulk carriers. IACS Requirements 1998, S24. IACS (1999), Hull surveys of bulk carriers, IACS Requirements, 1999, Z.10.2, Rev. 9. IACS (2000a), Side structures in single side skin bulk carriers. IACS Requirements 2000, S12, Rev. 3. IACS (2000b), Longitudinal strength of hull girder in flooded condition for bulk carriers. IACS Requirements 2000, S17, Rev. 3. IACS (2000c), Evaluation of scantlings of corrugated transverse watertight bulkheads in bulk carriers considering hold flooding. IACS Requirements 2000, S18. Rev. 2.

20 IACS (2000d), Evaluation of scantlings of the transverse watertight corrugated bulkhead between cargo holds Nos. 1 and 2, with cargo hold No. 1 flooded, for existing bulk carriers. IACS Requirements 2000, S19, Rev. 4. IACS (2000e), Evaluation of allowable hold loading for bulk carriers considering hold flooding. IACS Requirements 2000, S20, Rev. 2. IACS (2000f), Evaluation of allowable hold flooding of cargo hold No. 1 with cargo hold No. 1 flooded, for existing bulk carriers. IACS Requirements 2000, S22, Rev. 2. IMO MSC/Circ.829 & MEPC/Circ.335: Interim Guidelines for the Application of Formal Safety Assessment (FSA) to the IMO Rule-Making Process, 1998. IMO (1974), SOLAS 1974 as amended. IMO (2000), SOLAS 1998 amended 1999. INTERCARGO, Bulk Carrier Casualty Report - An analysis of vessel losses and fatalities - Statistics for 1999 and ten years of losses 1990-1999, www.intercargo.org International Conference on Load Lines (1966), Final Act of the conference with attachments including the International Convention on Load Lines, 1966, IMO London, 1981. Intercargo (2000), Bulk Carrier Casualty Report An analysis of vessel losses and fatalities, Statistics for 1999 and ten years of losses 1990-1999, www.intercargo.org, London, 2000. LMIS (1995): Ships Editorial, Casualty System Guide. Maritime Information Publishing Group, 1995. LMIS (1999), Lloyd s Maritime Information Services, Casualty Database, April 1999 version. LMIS (2000), Lloyd s Maritime Information Services, Casualty Database, August 2000 version. LMIS (2000), Lloyd s Maritime Information Service, Casualty Database, 2000. LR (1978-1998), Lloyd s Statistical Tables, Lloyd s Register of Shipping, 1978-1998. LR (2000), Lloyds Register of Shipping, World Fleet Statistics 1999. MCA (2000), Hazard identification as circulated by MCA on 25 April 2000 (IACS message 0032_IAe). MSC 72/INF.4, Hazard Identification of the Watertight Integrity of the Fore End of Bulk Carriers, submitted by IACS, 28 Jan 2000

21 MSC 73/INF.10, An Interim Report on FSA Study on Bulk Carrier Safety, submitted by Japan, 22 Sept 2000 MSC 72/4/1/Add. 1: Further green sea loads results of seakeeping model tests on a range of bulk carriers, dated 14 th of March 2000, submitted by UK MSC 70/4, Sensitivity of wetness and deck loads to bow height and forward buoyancy reserves in extreme weather conditions, submitted by the United Kingdom. MSC 70/4/6, Operational measures for avoiding dangerous situations in extreme weather conditions, submitted by Greece. MSC 72/4/1 Green sea loads on hatch covers and deck wetness derived from seakeeping model tests on a range of bulk carriers, submitted by the United Kingdom. MSC 72/4/1/Add. 1: Further green sea loads results of seakeeping model tests on a range of bulk carriers, submitted by the United Kingdom. MSC 72/16, Formal Safety Assessment, Decision Parameters including Risk Acceptance Criteria, submitted by Norway. MSC72/INF.7, submitted by Japan, 2000.