3-15.guide To The Design and Testing.2018 [PDF]

Zitiervorschau

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TECHNICAL AND RESEARCH BULLETIN NO. 3-15 (2018)

Guide to the Design and Testing of Anchor Windlasses Prepared for the Ship’s Machinery Committee By

Prasad Mantravadi, Senior Principal Engineer American Bureau of Shipping

Published by

The Society of Naval Architects and Marine Engineers 99 Canal Center Plaza, Alexandria, VA 22314 USA Copyright  2018 by the Society of Naval Architects and Marine Engineers with rights reserved.

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This Bulletin was prepared by Prasad Mantravadi, Senior Principal Engineer American Bureau of Shipping Under direction from

THE SHIP’S MACHINERY COMMITTEE for

THE SOCIETY OF NAVAL ARCHITECTS AND MARINE ENGINEERS TECHNICAL AND RESEARCH PROGRAM Prepared by a Working Group of Ship Production and Machinery Committee Working Groups and Volunteers Mr. Frederick (“Rick”) H. Ashcroft, Working Group Chair Reviewed and Approved by THE SHIP’S MACHINERY COMMITTEE Richard Delpizzo, Committee Chair

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Guide to the Design and Testing of Anchor Windlasses By Prasad Mantravadi, Senior Principal Engineer American Bureau of Shipping

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Table of Contents ACKNOWLEDGMENTS ................................................................................................ IX NOMENCLATURE: LIST OF DEFINITIONS AND SYMBOLS ....................................... X DEFINITIONS: ................................................................................................................. X 1.0 1.1 1.2 1.3 1.4 2.0 2.1 3.0 3.1

INTRODUCTION .................................................................................................... 1 HISTORY ............................................................................................................... 1 SUPERSESSION ..................................................................................................... 1 PURPOSE .............................................................................................................. 1 SCOPE .................................................................................................................. 1 TYPES OF ANCHOR WINDLASSES .................................................................... 1 SPECIFICATION OF EQUIPMENT ............................................................................... 2 DESIGN ................................................................................................................. 3 MECHANICAL DESIGN ............................................................................................ 3

4.0 ELECTRIC DRIVE ................................................................................................... 5 4.1 ELECTRIC MOTOR .................................................................................................... 5 4.2 DEGREE OF PROTECTION.......................................................................................... 5 5.0

HYDRAULIC DRIVE .............................................................................................. 5

6.0 REDUCTION GEAR ................................................................................................. 6 7.0 SHOP TESTING....................................................................................................... 6 8.0 ON-BOARD/SEA TRIAL TESTS ............................................................................. 7 9.0 MARKINGS .............................................................................................................. 7 APPENDICES: ................................................................................................................ 8 APPENDIX 1: APPENDIX 2: APPENDIX 3: APPENDIX 4:

ANCHOR TYPES ...................................................................................... 8 WILDCAT EXAMPLE ................................................................................. 8 CHAIN GRADES AND BREAKING STRENGTHS ............................................. 8 ANCHORING EQUIPMENT FROM IACS UR A1 ............................................ 8

APPENDICES: ................................................................................................................ 9 APPENDIX 1: ANCHOR TYPES ......................................................................................... 9

Stockless Anchors ....................................................................................................................... 10 US Navy Anchor and Weight Chart.............................................................................................. 11 Pawl Type Chain Stopper ............................................................................................................. 12 Devils Claw ................................................................................................................................... 12 APPENDIX 2: WILDCAT .................................................................................................. 13 APPENDIX 3: CHAIN GRADES AND BREAKING STRENGTHS1 ............................................. 14 vii

Unstudded Short-link Chain ......................................................................................................... 16

................................................................................................................................... 16 APPENDIX 4: ANCHORING EQUIPMENT2 .......................................................................... 17 APPENDIX 5: WINDLASS TYPES ..................................................................................... 19

Single Horizontal Anchor Windlass ............................................................................................. 19 ....................................................................................................................................................... 19 Double Horizontal Anchor Windlass............................................................................................ 20 Vertical Anchor Windlass ............................................................................................................. 21 ....................................................................................................................................................... 21 Vertical Anchor Windlass (Right Angle) ...................................................................................... 22

ATTACHMENT 1 .......................................................................................................... 23 BIBLIOGRAPHY/REFERENCES ................................................................................. 25

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ACKNOWLEDGMENTS The committee gratefully acknowledges the contributions of the members of the Society, Industry, and Government who have been generous in assisting the Author in accomplishing this task.

DISCLAIMERS This guide is intended to be advisory only. There is no implication of warranty by SNAME that successful performance of the recommended trials will ensure that a ship will comply with the requirements of the contract specifications, regulatory bodies or classification societies, or that it will perform satisfactorily and safely in service. The opinions or assertions of the authors are not to be construed as official or reflecting the views of SNAME or any government agency. It is understood and agreed that nothing expressed herein is intended or shall be construed to give any person, firm, or corporation any right, remedy, or claim against SNAME or any of its officers or members.

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NOMENCLATURE: LIST OF DEFINITIONS AND SYMBOLS Definitions: ABS: American Bureau of Shipping, www.eagle.org AGMA: American Gear Manufacturers Association, www.agma.org Devil’s Claw: A device that is used as a chain stopper to grab and hold an anchor chain. It consists of a turnbuckle, usually attached at the base of the anchor windlass, and a metal hook with two curved fingers that grab one link of chain. After hoisting the anchor and setting the windlass brake, the claw is placed on a chain link and the turnbuckle is tightened to take up the tension on the chain. If more than one stopper is used, the turnbuckles can be adjusted to evenly distribute the load. A devil's claw cannot be released while it is under tension. To release it, the tension must first be taken up by the windlass. Then the turnbuckle can be loosened and removed. Equipment Numeral: The design basis of anchoring equipment based on vessel particulars and calculated as per equations provided in IACS UR A1. High Holding Power (HHP) Anchor: An anchor with a holding power of at least twice that of an ordinary stockless anchor of the same mass. IACS: International Association of Classification Societies, www.IACS.org.uk ISO: International Organization for Standardization. Gypsies or Wildcats or Cable Lifter and Warping Head: Wildcat is a rotating member specially contoured to receive assembled chain links and connecting links around the circumference of the member and of suitable strength to impart motion to the chain when rotated. The wheels on either a vertical or horizontal windlass provide for either chain or line to be engaged. The wheel for line is termed a warping head, while the chain handling wheel is variously referred to as the gypsy (in the UK) or wildcat (in North America) or cable lifter (ISO 4568). For clarity in communication the generic term chain wheel is often used. It is important that the chain wheel match the chain size (i.e. the link pitch) closely. Even a small difference in link size or consistency can cause undue wear on the chain wheel and/or cause the chain to jump off the windlass when the winch is operating, particularly during payout, a runaway condition sometimes referred to as "water spouting" should it occur at high speed. ASTM F765-93 covers the wildcats as used on windlasses. Stockless Anchors: Commonly adopted anchors; mass of the heads (including pins and fittings) are not to be less than 60% of the total mass of the anchor. The mass of each bower anchor is given in IACS UR A1, Table 1. Super High Holding Power (SHHP) Anchor: An anchor with a holding power of at least four times that of an ordinary stockless anchor of the same mass.

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1.0 INTRODUCTION The Society of Naval Architects and Marine Engineers (SNAME) T&R Bulletin 3-15 (2018) Guide to the Design and Testing of Anchor Windlasses supersedes T&R Bulletin 3-15 (1964).

1.1 History The Guide for the Design and Testing of Anchor Windlasses was originally produced by Machinery Panel M-14 of the Ship’s Machinery Committee in 1964, reprinted in 1966 and 1972. The present version of, this Guide has been developed by updating the 1972 Guide incorporating ABS and other Class Societies’ requirements based on IACS Unified Requirement A1, Anchoring Equipment, and A3, Anchor Windlass Design and Testing, as well as other International Standards such as ISO 4868.

1.2 Supersession The Society of Naval Architects and Marine Engineers (SNAME) T&R Bulletin 3-15 (2018), Guide to the Design and Testing of Anchor Windlasses, supersedes T&R Bulletin 3-15 (1964), Guide to the Design and Testing of Anchor Windlasses for Merchant Ships.

1.3 Purpose The purpose of the Guide is to provide guidance for the design and testing of marine anchor windlasses.

1.4 Scope The design criteria are intended to cover all types of power driven anchor windlasses. Nothing in this Guide should be construed to delete or modify requirements of specified Regulatory Bodies.

2.0 Types of Anchor Windlasses There are basically two types of windlasses. The “Horizontal Type” is self-contained for mounting on the forecastle deck level. The “Vertical Type” or “Capstan Type” windlass is mounted close to the forecastle deck: their vertical shafts are driven by machinery usually located in the deck below the forecastle deck. Power driven anchor windlasses are usually driven through a reduction gear. The addition of warping heads (usually on intermediate shafts) enables the windlass to be used as a warping winch or mooring winch for handling mooring lines as well as for hoisting anchors. There are mainly two types of power used to drive windlasses: a) Hydraulic Motor Driven b) Electric Motor Driven A hybrid system is also emerging and available. Here, the normal loads are covered by AC electric motor and a hydraulic motor supplements providing quick response during load peaks. 1

2.1 Specification of Equipment The design basis of anchoring equipment is the “Equipment Numeral” (or EN) for ships operating in unrestricted waters, and is provided in IACS Recommendation 10 titled “Anchoring and Mooring Equipment” and IACS Unified Requirement (UR) A1. Reduction of the Equipment Numeral may be considered for ships operating in restricted service. EN is calculated as per guidelines in UR A1.2 based on vessel particulars. Based on the calculated EN number, the specifications of the required anchoring equipment for the vessel are obtained. The details include number of stockless bower anchors (mostly 2 anchors), mass per anchor, and diameter of the stud link chain cables for the bower anchors & the total length of chain. IACS UR A1 provides the anchoring equipment required for temporary mooring of a ship within harbor or sheltered area when the ship is awaiting berth, tide etc. for EN numbers 205 and above. IACS Recommendation 10 provides requirements for vessels with EN numbers 50 ≤ 205. Recommendation 10 may also be referenced for ships operating in unrestricted service. Reductions of the equipment may be considered for ships operating in restricted service. a) Anchor mass & type shall be specified. Anchor mass depends on the type of anchor selected. There are three types of anchors as shown in IACS UR A1: i) Ordinary Stockless Anchors ii) High Holding Power Anchors iii) Super High Holding Power Anchors b) Chain or Cable size, grade and length: Based on calculated EN, the required diameter of stud link chain size can be obtained from IACS UR A1, Table 1. Based on the material of construction, there are 3 grades of chain cables. Table 1 Chain Cables Material Mild Steel Special Quality Steel Extra Special Quality Steel

Grade 1 2 3

Range of UTS in N/mm2 300 to 490 491 to 690 >690

Wire rope may be used in place of chain cable on ships based on ship size and restricted service at the discretion of the Class Society. c) Hoisting Speed: The mean speed of the chain cable during hoisting of the anchor and cable is to be at least 9 m/min. d) Continuous Duty Pull: Force the windlass prime mover is to be able to exert for at least 30 minutes at continuous duty. e) Brake Capacity: The capacity of the windlass brake is to be sufficient to stop the anchor and chain cable when paying out the chain cable. f)

Chain Cable Stopper: Chain Cable stopper fitted or not.

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3.0 Design The design criteria are intended to cover hydraulic or electric power driven anchor windlasses based on IACS UR A3.

3.1 Mechanical Design a) Design Loads i)

Holding Loads: Calculations are to be made to show that, in the holding condition (single anchor, brake fully applied, and chain cable lifter declutched), and under a load equal to 80% of the specified minimum breaking strength of the chain cable (such as given in the ABS Steel Vessel Rules 2-2-2/Table 2 and 2-2-2/Table 3), the maximum stress in each load bearing component will not exceed yield strength (or 0.2% proof stress) of the material. For installations fitted with a chain cable stopper, 45% of the specified minimum breaking strength of the chain cable may instead be used for the calculation.

ii) Inertia Loads: The design of the drive train, including prime mover, reduction gears, bearings, and clutches, shafts, wildcat and bolting is to consider the dynamic effects of sudden stopping and starting of the prime mover or chain cable so as to limit inertial load. b) Continuous Duty Pull (Zcont1): The windlass prime mover is to be able to exert for at least 30 minutes a continuous duty pull (e.g., 30-minute short time rating corresponding to S2-30 minutes of IEC 60034-1), Zcont1 corresponding to the grade and diameter, d, of the chain cables in mm or inches as follows: Table 2 Continuous Duty Pull (Zcont1), for units in N or kgf or lbf Grade 1 Chain Grade 2 Chain Grade 3 Chain Units of d

37.5d2 N 42.5d2 N 47.5d2 N mm

3.82d2 kgf 4.33d2 kgf 4.84d2 kgf mm

5425.7d2 lbf 6149.1d2 lbf 6872.5d2 lbf in

The values of the above table are applicable when using ordinary stockless anchors for anchorage depth down to 82.5 m (270 ft). For anchorage depth deeper than 82.5 m (270 ft), a continuous duty pull Zcont2 is: Zcont2 = Zcont1 + (D – 82.5) x 0.27d2 N Zcont2 = Zcont1 + (D – 82.5) x 0.0275d2 kgf Zcont2 = Zcont1 + (D – 270) x 11.86d2 lbf where D is the anchorage depth, in meters (feet for use with lbf). The value of Zcont1 is based on the hoisting of one anchor at a time, and assumes that the effects of buoyancy and hawse pipe efficiency (assumed to be 70%) have been accounted for. In general, stresses in each torque-transmitting component are not to exceed 40% of yield strength (or 0.2% proof stress) of the material under these loading conditions.

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c) Overload Capability: The windlass prime mover is to be capable of providing the necessary temporary overload capacity for breaking out the anchor. This temporary overload capacity or “short term pull” is to be at least 1.5 times the continuous duty pull applied for at least 2 minutes. The speed during this operation may be lower than normal. d) Hoisting Speed: The mean speed of the chain cable during hoisting of the anchor and cable is to be at least 9 m/min. For testing purposes, the speed is to be measured over two shots of chain cable (55 m or 30 fathoms in length), and with three shots of chain (82.5 m or 45 fathoms in length) and the anchor submerged and hanging free. e) Brake Capacity: Where a chain cable stopper is not fitted, the brake is to produce a torque capable of withstanding a pull equal to 80% of the specified minimum breaking strength of the chain cable without any permanent deformation of strength members and without brake slip. Where a chain cable stopper is fitted, 45% of the breaking strength may be applied instead. f)

Chain Cable Stopper: For each chain cable, there shall normally be a chain cable stopper, arranged between windlass and hawse pipe. Chain cable stopper, if fitted, along with its attachments is to be designed to withstand, without any permanent deformation, 80% of the specified minimum breaking strength of the chain cable. Consideration is to be given to means to contain debris consequent to a severe damage of the windlass motor due to overspeed resulting from the uncontrolled rendering of the cable, particularly when an axial piston type hydraulic motor is used.

g) Wildcat or Cable Lifter: The mean pitch diameter of the wildcat should be at least:

𝐷𝐷𝐷𝐷 = [

10(4) 𝜋𝜋

](d)

where 𝐷𝐷𝐷𝐷 is wildcat pitch diameter and d is the chain cable diameter.

The wildcat should have at least 5 snugs or whelps. Materials and manufacture of wildcat shall conform to ASTM F765. Each cable lifter or wildcat shall be fitted with a hand brake, which may be remotely controlled and which is capable of applying a brake torque sufficient to maintain a load equal to the holding load equal to the brake capacity indicated in 3.1 e) above. h) Couplings/Clutches: Windlasses are to be fitted with couplings/sliding jaw clutches which are to be capable of disengaging the cable lifter from drive shaft. Hydraulically or electrically operated couplings are to be capable of being disengaged manually. i)

Warping Head or Ends: Warping ends may be fitted on to the intermediate shaft or on the wildcat shaft.

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Protection of Mechanical Components: To protect mechanical parts, including component housings, a suitable system is to be fitted to limit the speed and torque at the windlass motor. Consideration is to be given to a means to contain debris created as a consequence of severe damage to the windlass motor due to overspeed resulting from an uncontrolled rendering of the cable, particularly when an axial piston type hydraulic motor is used.

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4.0 Electric Drive Machines operated on an A.C. supply require a means of speed control with either pole-changing or slipring motors being used. Slip-ring motors require low starting currents, but waste power at less than full speed and require regular maintenance. Pole-changing motors are of squirrel cage construction, allowing for multiple speeds. While they require large starting currents, maintenance requirements are negligible. A permanent magnet motor drive option is also available which have better dynamic capabilities and controllability. Apart from the advantages and disadvantages for each of the drive and control methods, all electric drives have difficulty with heavy continuous overloads. Each system has its advantages, and careful design and choice of associated equipment can provide a satisfactory installation. Electrically driven windlasses shall be provided with a torque limiting device. Electric motors of 100 kW (135 HP) and over are to be certified by a Class Society. Electric motors of less than 100 kW are to be designed, constructed, and tested in accordance with established industrial practices and manufacturer’s specifications. Manufacturer’s test for electric motors less than 100 kW are to include tests required as per Class Society’s requirements regardless of standard of construction. Test certificates are to be made available upon request.

4.1 Electric Motor The size and capacity of an anchor windlass electric drive for normal design requirements shall be determined by its specified duty and the following criteria: a) Electric motors shall meet Class Society requirements. The windlass motor is to be able to exert for at least 30 minutes a continuous duty pull (e.g., 30-minute short time rating corresponding to S2-30 minutes of IEC 60034-1); b) Motors installed in weather are to have enclosures suitable for the location. c) Motor branch circuits are to be protected in accordance with the provisions of the Class Society. Electrical cables installed in locations subjected to the sea are to be provided with effective mechanical protection. d) Electric windlasses shall be provided with an automatic braking system which engages when the operating device is in the stop or braking position or when there is no power on the windlass. The brake shall be capable of holding a load on the chain cable of 1.5 times the working load of the windlass.

4.2 Degree of Protection Electrical drives and control equipment shall conform to the requirements of IEC 60092. Open deck enclosures shall conform to IEC 60529 and/or appropriate degree of protection for the service and environment in which the equipment is installed.

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Hydraulic Drive

The hydraulic anchor windlass (also known as electro- hydraulic anchor windlass) is an anchor windlass which relies mainly on the hydraulic power to carry out and control the action. Its hydraulic energy originates from the electric motor driven oil pump device. There are three types hydraulic drives based on the hydraulic pressure: a) Low Pressure b) Medium Pressure c) High Pressure 5

Hydraulic systems are to comply with the provisions of the Class Society. A suitable system of braking that is capable of holding a load on the chain cable of at least 1.3 times the working load of the windlass. The relief valve lifting pressure shall be set accordingly.

5.1 Low Pressure Systems Low pressure systems are systems that have a maximum operating pressure of less than 60-70 bar. Lowpressure systems use the open-loop circuit, are simple in design, have excellent dynamic performance and reliability. However, the equipment is large. Where considerable amounts of hydraulic machinery are fitted, the live-circuit, supplied by a centralized hydraulic power system, may be more economical.

5.2 Medium Pressure Systems These are systems that operate at maximum pressures of greater than 100 bar and less than 200 bar.

5.3 High Pressure Systems These are systems that operate at maximum pressures of greater than 200-250 bar.

6.0 Reduction Gear Gearing shall be designed to conform to recognized standards such as AGMA or other international standards. Reduction gears over 100 kW are to be certified by a Class Society.

7.0 Shop Testing Windlasses are to be inspected during fabrication at the manufacturer’s facilities by a Class Society Surveyor for conformance with the approved plans. Acceptance tests, as given in the specified standard of compliance, are to be witnessed by the Surveyor and, as a minimum, include the following tests: a) No-load test. The windlass is to be run without load at rated speed in each direction for a total

of 30 minutes. If the windlass is provided with a gear change, an additional run in each direction for 5 minutes at each gear change is required.

b) Load test. The windlass is to be tested to verify that the continuous duty pull, overload capacity,

and hoisting speed as specified In Section 3.1 can be attained. Where the required “load testing”, including “overload” capacity of the entire windlass unit, is not possible or practical to conduct at the shop, the manufacturer may submit powering calculations demonstrating that the windlass motor is capable of attaining the hoisting speed, the required continuous duty pull, and the overload capacity. These calculations are to be validated through testing of an anchor windlass unit. Once these calculations are validated, they may be used in place of the load tests within the scope of the calculations. Further, in addition to other testing requirements, each windlass motor is to be tested at the shop to verify its ability to meet the calculated power requirements. Where the windlass motor is a hydraulic motor, in addition to the hydraulic motor, the hydraulic pump is also to be tested at the shop. During the testing, the input/output torque, speed, delivery pressures, and flow rates of the pump and the hydraulic motor are to be measured, as appropriate.

c)

Brake capacity test. The holding power of the brake is to be verified either through testing or by calculation.

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Where the vendor/manufacturer does not have adequate facilities, these tests, including the adjustment of overload protection can be carried out at the shipyard prior to installation or on board ship. In these cases, functional testing at the manufacturer is to be performed under no-load conditions.

8.0 On-Board/Sea Trial Tests Each windlass is to be tested under working conditions after installation on board to demonstrate satisfactory operation. Each unit is to be independently tested for braking, clutch functioning, lowering and hoisting of chain cable and anchor, proper riding of the chain over the chain lifter, proper transit of the chain through the hawse pipe and the chain pipe, and proper stowage of the chain and the anchor. It is to be confirmed that anchors properly seat in the stored position and that chain stoppers function as designed if fitted. The mean hoisting speed, as specified, is to be measured and verified. The braking capacity is to be tested by intermittently paying out and holding the chain cable by means of the application of the brake. Where the available water depth is not available at time of test, an alternative test method may be proposed for special consideration.

9.0 Markings Windlasses are to be permanently marked with the following information: a) Nominal size of chain (e.g. 100/3/45 is the size designation of a windlass for 100 mm diameter chain cable of Grade 3, with a holding load of 455 of the breaking load of the chain cable.) b) Maximum Anchorage Depth, in meters

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Appendices: Appendix 1: Appendix 2: Appendix 3: Appendix 4: Appendix 5:

Anchor Types Wildcat Example Chain Grades and Breaking Strengths Anchoring Equipment from IACS UR A1 Windlass Types

Addendum 1: Additional Design and Testing Requirements for U.S. Navy Auxiliary and Special Purpose Ships

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Appendices: Appendix 1: Anchor Types

Source: SOTRA Anchor & Chain

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Stockless Anchors

Source: SOTRA Anchor & Chain

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US Navy Anchor and Weight Chart

Source: SOTRA Anchor & Chain

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Pawl Type Chain Stopper

Source: Washington Chain & Supply Devils Claw

Source: Washington Chain & Supply

Source: Marine Crewman’s Handbook (Department of the Army), FM 55-501 (December 1999) 12

Appendix 2: Wildcat

Source: Schoellhorn-Albrecht Machine Co., Inc.

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Appendix 3: Chain Grades and Breaking Strengths1

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Unstudded Short-link Chain

_________________________________ 1

ABS Steel Vessel Rules (2017), Part 2 Chapter 2 Section 2 Anchor Chain

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Appendix 4: Anchoring Equipment2

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_________________________________ 2

(IACS UR A1 March 2017)

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Appendix 5: Windlass Types Single Horizontal Anchor Windlass

Source: Schoellhorn-Albrecht Machine Co., Inc.

Source: Schoellhorn-Albrecht Machine Co., Inc 19

Double Horizontal Anchor Windlass

Source: Schoellhorn-Albrecht Machine Co., Inc.

Source: Schoellhorn-Albrecht Machine Co., Inc.

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Vertical Anchor Windlass

Source: Schoellhorn-Albrecht Machine Co., Inc

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Vertical Anchor Windlass (Right Angle)

Source: Schoellhorn-Albrecht Machine Co., Inc

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ATTACHMENT 1 ADDITIONAL DESIGN AND TESTING REQUIREMENTS FOR U.S. NAVY AUXILIARY AND SPECIAL PURPOSE SHIPS The purpose of this addendum is to provide additional information specific to the design, construction, and testing of anchor windlass systems onboard U.S. Navy auxiliary and special purpose ships. These ships are typically built to commercial specifications. However, due to the manner in which the ships are operated and maintained, it is prudent to levy additional “owner’s requirements”. 1. Design Criteria – a. b. c. d. e. f.

g.

h.

The anchor system shall meet the applicable regulatory body and classification society requirements, the additional requirements specified herein, and any additional “owner’s requirements” contained within the ship design and construction contract. A balanced fluke anchor is preferred, to better enable three points of contact between the hull and anchor when housed. The use of other anchor designs shall be approved by the Government prior to proceeding with the design process. A straight chain run shall be used from the windlass to the chain stopper or hawse pipe, as practicable (especially when ship is configured with an anchor pocket). All design calculations and drawings submitted to the regulatory body or classification agent by the shipyard, or their vendor, shall be provided concurrently to the Government in accordance with data requirements of the contract. Wildcats shall be in accordance with ASTM F765. The dimensional, and whelp and pocket shape requirements of Section 7 of ASTM F765 shall apply to all anchor wildcats, regardless of ASTM F765 wildcat Type (I, II, III or IV). The electric motor shall comply with IEEE Standard 45 and be rated for 30 minutes full windlass or warping duty following 30 minutes of idle pump operation. The electric motor shall meet the anchor handling requirements without exceeding 125% of its continuous duty rated current. All parameters requiring verification shall be identified during the design phase, and a verification matrix provided with the design calculations. The verification matrix shall include the verification method, a range of acceptability for the parameter, and identification of when the verification will be completed. Parameters requiring more than one method of verification (i.e. analysis followed by testing) shall include an entry for each method that applies. To verify anchor handling system layout and operation, a 1:5 scale anchor handling model shall be produced for all first of class and existing ship designs with design modifications that may affect the operation or configuration of the anchoring system. Scale model testing shall be used to verify: 1) The three points of contact between the anchor and vessel when housed and secured for sea; 2) The anchor flukes will not get caught in the hawsepipe during retrieval; and, 3) The appropriate contact between the anchor chain and the deck bolsters and hawsepipe and the friction between the ship and chain will be minimized. 4) The system will meet the ABS Classification requirements, and perform in accordance with the guidelines of INSURVINST 4730.1. 5) The anchor’s housed position shall be located above the bow wave generated at full power in calm sea conditions. The model shall be constructed from the hull lines, half-hull from the main deck level to the hull bottom. The model shall include the anchor to scale along with the associated chain and swivels, shell bolster (removable or adjustable), hawsepipe, hawsepipe bellmouth and deck bolster (removable or adjustable). The model shall have a mechanism to raise and lower the anchor/chain. The anchor/chain assembly shall be constructed to ensure that it simulates 23

the characteristics and functions of the full-scale anchor/chain assembly such as, but not limited to: dimension, center of gravity, and moment of inertia. 2. Testing – Shop testing and ship installation testing shall be accomplished in accordance with the requirements of SNAME T&R Bulletin 3-39. At-sea testing shall be accomplished in accordance with the following procedure, which is based on requirements from SNAME 3-15 and is consistent with the testing requirements of ABS SVR 3-7-2/1, as required by ABS SVR 4-5-1/9. Once the ship is in the requisite depth of water (50 fathoms), conduct the at-sea testing according to the following procedure: a. Lower one anchor to the water’s edge using the windlass. b. Set the hand brake and secure power to the anchor windlass. Slowly release the hand brake to ensure the fail safe brake holds. c. Set the hand brake, restore power, and disengage the wildcat. d. Using the hand brake only, lower the anchor, stopping at approximately 15, 30 and 45 fathoms. e. Engage the wildcat and raise the anchor from 45 fathoms to 15 fathoms, recording appropriate data and observations. f. Raise the anchor until it is housed, engage a stopper/pelican hook on the tested anchor and disengage the wildcat. g. Repeat test steps 2.a through 2.f on the other anchor. h. For lead ship designs, or ships with new anchor system designs, at-sea testing shall also include a demonstration in shallow water (less than 100 feet) using an approximate 3 to 1 chain scope. Anchor shall be set on the bottom by applying an astern strain until the vessel holds, followed by breaking the anchor free, retrieving and housing. Propulsion power shall only be used to maintain position of the ship, not to assist with breaking the anchor free of the bottom. The technical point of contact for this issue is the Director, Auxiliary and Special Mission Ship Design (NAVSEA 05D4), at Naval Sea Systems Command, Washington, DC.

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BIBLIOGRAPHY/REFERENCES

ABS Rules for Building and Classing Steel Vessels. (2017). Houston, TX: American Bureau of Shipping. IACS Recommendations No. 10, Rev. 3 “Anchoring, Mooring and Towing Equipment. (December 2016). London, United Kingdom: International Association of Classification Societies, p. 20. IACS UR A1/UR A2/UR A3, Unified Requirements for Anchoring Equipment. (March 2017). London, United Kingdom: International Association of Classification Societies, p.34. IEC 60034-1: Rotating electrical machines - Part 1: Rating and performance. (2017). Geneva, Switzerland: International Electrotechnical Commission. ISO 4568: Shipbuilding - Sea-Going Vessels - Windlasses and Anchor Capstans. (2006). 3rd ed. Geneva, Switzerland: International Organization for Standardization. ISO 6325: Shipbuilding – Cable Stoppers (1987). 2nd ed. Geneva, Switzerland: International Organization for Standardization. ASTM F765-93: Standard Specification for Wildcats, Ship Anchor-Chain. UK MAIB Report No. 25/2009, Report on the investigation of the catastrophic failure of a windlass hydraulic motor on board Stellar Voyager off Tees Bay resulting in a major injury on 23 March 2009 MIL-DTL-32572 (NAVY) 21 February 2017, Detail Specification, Anchor Windlass, Electro-Mechanical, Vertical, Two Speed and Variable-Speed

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