Easy Rider Mooring. Design Assessment. For. Advanced Mooring Technology CONSTRUCTION. Authorised:

Size: px

Start display at page:

Download "Easy Rider Mooring. Design Assessment. For. Advanced Mooring Technology CONSTRUCTION. Authorised:"

Dennis Ross
6 years ago
Views:

M C A L P I N E M A R I N E D E S I G N P T Y L T D ACN 003 056 399 Easy Rider Mooring Design Assessment For Advanced Mooring Technology Project No. 04003 Rev.

1 M C A L P I N E M A R I N E D E S I G N P T Y L T D ACN Easy Rider Mooring Design Assessment For Advanced Mooring Technology Project No Rev. 0 Status: Authorised: CONSTRUCTION / / Copyright This document, including the conceptual content thereof and any specifications and particulars thereto, is an integral part of the intellectual property of. This document is not to be reproduced or copied, in whole or in part or loaned or otherwise communicated to any third party or used in any manner detrimental to the interests of without said company s express consent. Acceptance of this document shall be construed as agreement to comply with the aforesaid terms and conditions. 117 Marine Terrace, Fremantle, Western Australia, 6160 Phone Fax @compuserve.com

2 Easy Rider Mooring Page 2 of 14 Contents 1 INTRODUCTION AND DESIGN NOTES MOORING LOADINGS CONCRETE CLUMP WEIGHTS VESSEL PROFILES MOORING COMPONENTS MATERIAL PROPERTIES MOORING COMPONENT DATA MOORING COMPONENT ANALYSIS MOORING COMPONENT SUMMARY MOORING ARRANGEMENT... 6

3 Easy Rider Mooring Page 3 of 14 1 Introduction and Design Notes This report demonstrates the suitability of the Easy Rider Mooring system to moor yachts and powerboats in the range of 8m to 10m in length. The expected mooring loads for vessels of this size at a given maximum wind strength are presented. This report details working load limits for individual components of the Diver I Diver II Easy Rider Mooring system. For the purposes of determining the working load limit, a factor of safety of 3.5 has been assumed which is consistent with standard commercial mooring practice. This analysis takes no account of the adequacy of the hawser or mooring bollards and associated structure on or within the vessel. The vessel owners must ensure the hawser, bollards and structure are able to withstand the mooring loads. No assertion is made as to the structural adequacy or the adequacy of the stability of the vessel to withstand the loads and upsetting moments imposed in adverse conditions. The buoy bar is to be loaded approximately axially. To achieve this an adequate length hawser must be used. All shackle pins must be prevented from being loosened by movement of the mooring chains. An experienced marine surveyor must periodically survey the mooring. Any worn or corroded components must be replaced as soon as any damage becomes apparent. It is recommended that the mooring is surveyed after each significant storm event and that any components that show signs of deformation (yielding) or significant wear be replaced.

4 Easy Rider Mooring Page 4 of 14 2 Mooring Loadings Mooring loading calculations have been preformed for typical power and sailing vessels of lengths 8 and 10 metres. The results are presented graphically as Figure 1. The profiles and relevant particulars of the four vessels used can be found in 2.2 Vessel Profiles. Figure 1 plots mooring load (in tonnes) versus wind speed (in knots). There are two horizontal lines indicating the maximum holding capacity for one and two concrete clump weights respectively. For the purposes of this report the concrete clump weights have been taken as weighing 1 tonne in air. Where the vessels loading intersects either of these lines (whichever is applicable), a line should be projected down vertically and a maximum wind strength for that vessel on that particular mooring be read off. These loads should only be considered valid for vessels that fall generally within the ranges of windage area and displacements depicted in 2.2 Vessel Profiles. Vessels whose characteristics place them outside of those considered here should have their mooring loads assessed on an individual basis. Similarly these loads should only be considered valid for geographic locations where the significant wave height remains less than 0.55m and the current does not exceed 2 knots. Vessels moored in areas that exceed these limitations should again have their mooring loads assessed on an individual basis. 2.1 Concrete Clump Weights This report has been prepared based on the mooring systems being anchored using 1 tonne in air concrete clump weights either singularly or in arrays of two. In the field tests carried out by Diver I Diver II have established that the maximum holding power for their unburied 1 tonne concrete clumps is 460kg per weight on a sand seabed. Alternate anchoring systems could be substituted for the clump weight(s) provided the alternative demonstrated a holding power in excess of the clump weight(s) being replaced. Any substitution would have to demonstate the required holding power at any direction of loading.

5 Easy Rider Mooring Page 5 of 14 Figure 1 - Wind Speed vs Mooring Load m Power Boat 2.5 Mooring Load (tonnes) Clump Weights 10m Yacht 8m Power Boat 8m Yacht Clump Weight Wind Speed (knots)

6 Easy Rider Mooring Page 6 of Vessel Profiles 10m Power Boat 10m Yacht Length: 10.0 m Length: 10 m Profile Windage Area: 26.2 m 2 Profile Windage Area: 17.9 m 2 Frontal Windage Area: 7.8 m 2 Frontal Windage Area: 5.4 m 2 Displacement: 9.0 t Displacement: 6.0 t Windage Profile Windage Profile 8m Power Boat 8m Yacht Length: 8.0 m Length: 8.0 m Profile Windage Area: 14.5 m 2 Profile Windage Area: 12.5 m 2 Frontal Windage Area: 5.4 m 2 Frontal Windage Area: 3.4 m 2 Displacement: 2.5 t Displacement: 2.0 t Windage Profile Windage Profile

7 Easy Rider Mooring Page 7 of 14 3 MOORING COMPONENTS 3.1 Material Properties The majority of the components associated with the buoy bar, swivel and loops are fabricated from 316 Stainless Steel. The material properties of 316 Stainless Steel vary significantly from an ultimate tensile strength of 515 N/mm 2 up to 690 N/mm 2. For the purposes of this report the ultimate tensile strength of the 316 Stainless Steel used has been assumed to be 618 N/mm 2. It must be ensured that the material used in manufacturing all Stainless Steel components has an ultimate tensile strength equal to, or in excess of 618 N/mm 2 for this report to remain valid.

8 Easy Rider Mooring Page 8 of Mooring Component Data Anchor Data Concrete Clump Weights Diver I Diver II standard. 1 tonne weight in air. Shackles Locations Anchor & Riser Chain Size 16 mm dia Type Green Pin Safety Minimum Breaking Strength 191 kn Working Load 54.6 kn Factor of Safety 3.5 Chain Locations Riser & V Chain Size 20 mm dia Type General Link Proof Coil Minimum breaking strength 144 kn Weight in Air 8.26 kg/m Weight in Water 7.17 kg/m Working Load 41.1 kn Factor of Safety 3.5 Lower Loop on Buoy Bar Size 15.88mm dia Rod Material Grade 316 Stainless Steel Minimum breaking strength 146 kn Working Load 41.9 kn Factor of Safety 3.5

9 Easy Rider Mooring Page 9 of 14 Buoy Bar Size mm dia Rod Material Grade 316 Stainless Steel Thread ¾ UNC Minimum Breaking Strength 125kN Maximum Tension (Steady State Condition) 35.6 kn Factor of Safety 3.5 Swivel Tube Size 32 mm OD, 20 mm ID Tube Material Grade 316 Stainless Steel Bar Size mm dia Bar Material Grade 316 Stainless Steel Weld Size 6 mm (Throat thickness) Minimum Breaking Strength 146 kn Maximum Tension (Steady State Condition) 41.9 kn Factor of Safety 3.5

10 Easy Rider Mooring Page 10 of Mooring Component Analysis Material Properties Stainless Steel 316 σut = σy = 618 MPa 220 MPa τut = 371 MPa 60% Tensile τy = 132 MPa 60% Tensile Shaft, 316 Stainless Steel Unthreaded Tensile strength Diameter, Φ = mm Major Area, A = 285 mm 2 Yield Load = σy x A = 220x285 = N Yield Load = 6.39 t Ultimate Load = σut x A = 618 x 285 = N Ultimate Load = 17.9 t Threaded Tensile Strength, 3/4" UNC Thread Tensile Area, A T = 202 mm2 Yield Load = σy x A T = 220 x 202 = N Yield Load = 4.53 t Ultimate Load = σut x A T = 618 x 202 = N Ultimate Load = t

11 Easy Rider Mooring Page 11 of 14 Material Properties Stainless Steel 316 σut = σy = 618 MPa 220 MPa τut = 371 MPa 60% Tensile τy = 132 MPa 60% Tensile Loop, 316 Stainless Steel Tensile Strength Diameter, Φ = 12.7 mm Tensile Area, A T = 253 mm 2 Shear Strength Yield Load = σy x A T = 220 x 253 = N Yield Load = 5.7 t Ultimate Load = σut x A T = 618 x 253 = N Ultimate Load = 16.0 t Shear Area, A S = 253 mm 2 Yield Load = τy x A S = 132 x 253 = N Yield Load = 3.40 t Ultimate Load = τut x A S = 371 x 253 = N Ultimate Load = 9.57 t Swivel Tube Tensile Strength Outside Diameter, Φo = 32 mm Inside Diameter, Φi = 20 mm Cross Sectional Area, A x = 490 mm 2 Yield Load = σy x A x = 220 x 490 = N Yield Load = 11.0 t Ultimate Load = σut x A x = 618 x 490 = N Ultimate Load = 30.9 t Compressive strength Equal to Tensile, neglecting buckling

12 Easy Rider Mooring Page 12 of 14 Material Properties Stainless Steel 316 σut = σy = 618 MPa 220 MPa τut = 371 MPa 60% Tensile τy = 132 MPa 60% Tensile Connection between Swivel Tube & Loop Weld Strength Weld Size, S w = 6 mm Throat Thickness Weld Length, L w = Weld Leg Length, S wl = 40 mm 8 mm Weld Area, A w = (6 x 40) x 4 = 960 mm 2 Yield Load = τy x A w = 132 x 960 = N Yield Load = 12.9 t Ultimate Load = τut x A w = 371 x 960 = N Ultimate Load = 36.3 t

13 Easy Rider Mooring Page 13 of Mooring Component Summary Item No Item No Off Specification 1 Swivel 1 32 mm OD 20 mm ID Tube mm Round Bar 6 mm Fillet Weld (minimum) All Grade 316 Stainless Steel 2 Buoy Bar mm Round Bar ¾ UNC Nut Grade 316 Stainless Steel Breaking Load Working Load Limit 15.0 t 4.28 t 12.7 t 3.63 t 3 Lower Loop on Buoy Bar mm Round Bar 6 mm Fillet Weld (minimum) Grade 316 Stainless Steel 15.0 t 4.28 t 4 Lower Buoy Bar Shackle 1 16 mm diameter Grade S Shackles 19.5 t 5.57 t 5 Riser Chain 1 1m x 20 mm General Link Proof Coil Chain 14.7 t 4.20 t 6 Riser Shackle 1 16 mm diameter Grade S Shackles 19.5 t 5.57 t 7 V Chain 3 1m x 20 mm General Link Proof Coil Chain 14.7 t 4.20 t 8 Anchor Shackles 3 16 mm diameter Grade S Shackles 19.5 t 5.57 t 9 Anchor 3 Diver I Diver II Concrete Clump 1.0 tonnes weight per anchor Up to 0.46 tonnes holding capacity per anchor in sand Note:- 1. A Factor of Safety of 3.5 has been used to determine the Working Load Limit

14 Easy Rider Mooring Page 14 of 14 4 Mooring Arrangement

Chapter 2: Strain. Chapter 3: Torsion. Chapter 4: Shear and Moment Diagram

Chapter 2: Strain. Chapter 3: Torsion. Chapter 4: Shear and Moment Diagram Chapter 2: Strain Chapter 3: Torsion Chapter 4: Shear and Moment Diagram Strain - Is defined as change in length per unit length, simply put it is unit deformation L Stress and Strain Exist concurrently