Mooring Equipment Guidelines

1 The OCIMF mission is to be the foremost authorit y on the safe and environmentally responsible operation of oil tankers and terminals, promoting continuous improvement in standards of design and Companies International Marine ForumMooring Equipment Guidelines3rd Edition (MEG)Issued by theOil Companies International Marine ForumFirst Published 1992 Second Edition 1997 Third Edition 2008 ISBN 978 1 905331 32 1 Oil Companies International Marine Forum, BermudaBritish Library Cataloguing in Publication Data A catalogue record for this book is available from the British Oil Companies International Marine Forum (OCIMF) is a voluntary association of oil companies having an interest in the shipment and terminalling of crude oil and oil products.

2 OCIMF is organised to represent its membership before, and to consult with, the International Maritime Organization and other governmental bodies on matters relating to the shipment and terminalling of crude oil and oil products, including marine pollution and of UseThe advice and information given in this guide ( Guide`) is intended purely as guidance to be used at the user s own risk. No warranties or representations are given nor is any duty of care or responsibility accepted by the Oil Companies International Marine Forum (OCIMF), the membership or employees of OCIMF or by any person, firm, corporation or organisation (who or which has been in any way concerned with the furnishing of information or data, the compilation or any translation, publishing, supply or sale of the Guide)

3 For the accuracy of any information or advice given in the Guide or any omission from the Guide or for any consequence whatsoever resulting directly or indirectly from compliance with, adoption of or reliance on guidance contained in the Guide even if caused by a failure to exercise reasonable care on the part of any of the aforementioned & bound in Great Britain by Bell & Bain Ltd. Glasgow Published in 2008 by Witherby Seamanship International 4 Dunlop Square Deans Estate Livingston EH54 8SB United KingdomTel No: +44(0)1506 463 227 Fax No: +44(0)1506 468 999 Email: shipping industry has always been concerned with safe Mooring practices. A fundamental aspect of this concern entails the development of Mooring systems that are adequate for the intended service, with maximum integration of standards across the range of ship types and sizes.

4 To further this aim the Oil Companies International Marine Forum first published Mooring Equipment Guidelines in 1992 and this latest, third edition provides a major revision and update to the original content to reflect changes in ship and terminal design, operating practices and advances in technology. Although numerous standards, Guidelines and recommendations concerning Mooring practices, Mooring fittings and Mooring Equipment exist, where guidance is given it is often incomplete. For example, the number of hawsers and their breaking strength may be recommended without any advice on Mooring winch pulling force or brake holding capacity. These Guidelines provide an extensive overview of the requirements for safe Mooring from both a ship and terminal perspective and embrace the full spectrum of issues from the calculation of a ship s restraint requirements, the selection of rope and fitting types to the retirement criteria for Mooring broad-based working group was established by OCIMF to develop the text for this edition with the participation of OCIMF members and other industry associations, including the International Association of Independent Tanker Owners (INTERTANKO), the International Chamber of Shipping (ICS), the Society of International Gas Tanker and Terminal Operators (SIGTTO)

5 , the International Association of Classification Societies (lACS), the International Association of Ports and Harbors (IAPH), the Nautical Institute (NI) and the International Harbour Masters Association (IHMA). Valuable contributions were also received from representatives of rope manufacturers, winch manufacturers, Equipment suppliers, shipyards and specialist consultants. The following is an overview of some of the substantive changes included in this edition:Wind and current drag coefficients have been included from earlier OCIMF and SIGTTO publications that are now out of print. All coefficient data is now appended to the Guidelinesthe guidance has been expanded to account for site-specific conditions at terminals and the impact on Mooring patterns, prompting consideration of the need for more rigorous analysis incorporating vessel motion and dynamic force calculationsreference has been made to the content of IMO Guidance on Shipboard Towing and Mooring Equipment and related IACS Unified Requirements.

6 In addition, guidance on ship s fittings associated with both emergency towing, escorting and pull-back and harbour towing includes relevant content from the OCIMF publication Recommendations for Ships Fittings for Use with Tugs the concept of Design Basis Load` has been introduced for establishing the required strength of ship s Mooring fittings. The treatment of geometric effects, such as wrap angle on a fitting, has been modified to align with practices in other industries and is no longer automatically included within quoted safety factorsit is recommended that all ship s Mooring fittings should be designed to carry the MBL of the attached Mooring . The recommendations concerning the strength of ship s Mooring fittings are based on the principle of rope failure before fitting failure and fitting failure before hull or foundation failurerecommendations on the marking of fittings are aligned with the requirements of IMO MSC/1175, as adopted in SOLAS Chapter II I, Regulation 3-8full account has been taken of the introduction of new rope materials, such as those manufactured from High Modulus Polyethylene (HMPE), and the related impact on Equipment design and operation.

7 Relevant content from the OCIMF publication Guidelines on the Use of High-Modulus Synthetic Fibre Ropes as Mooring Lines on Large Tankers has been includedguidance on Mooring line tails has been revised in the light of industry experience, particularly with regard to their use at exposed berthsrevised guidance is appended on the inspection and maintenance of Mooring lines. These Guidelines represent best known Mooring technology and practice. It is recognised that it may not always be practical to retrofit all aspects of this technology to existing Mooring systems. For existing ships, where the Mooring arrangement does not meet the recommendations described in these Guidelines , both ship and terminal operators should be made aware of the limitations of the Mooring system and have IntroductionivMooring Equipment Guidelines 3rd Editioncontingency plans drawn up to deal with them.

8 The contingency plans should include (but not be limited to) predetermined environmental limits for berthing, stoppage of cargo loading or unloading, and departure from the to the recommendations contained in these Guidelines should only be introduced on the basis of a formal risk assessment and should be implemented through a proper change management process. The Guidelines address conventional and alternative Mooring systems, but this does not extend to arrangements and novel designs, such as those employing vacuum pads. In addition the Guidelines are not intended to apply to vessels operating in extreme publication attempts to refine, unify and update selected existing Guidelines and to add essential information that has either been omitted or poorly defined.

9 Care has been taken to ensure that the design performance of Equipment is optimised, while not overlooking the equally important factors of ease of handling and safety of personnel. These Guidelines represent a recommended minimum requirement and are intended to be useful to ship and terminal designers and operators. They are not intended to inhibit innovation or future technological advances. Although primarily addressing tankers and gas carriers, many of the recommendations are considered to be equally applicable to other vessel types. With the publication of this third edition, the following documents have been superseded and are removed from print:OCIMF Guidelines on the Use of High-Modulus Synthetic Fibre Ropes as Mooring Lines on Large Tankers (First Edition, 2002)OCIMF Recommendations for Ships' Fittings for Use with Tugs (First Edition, 2002)OCIMF Prediction of Wind and Current Loads on VLCCs (Second Edition, 1994)OCIMF/SIGTTO Prediction of Wind Loads on Large Liquefied Gas Carriers (First Edition, Reprinted 1995)

10 VContentsContentsIntroduction iiiList of Figures xList of Tables xiv1 Principles of Mooring General Forces Acting on the Ship Wind and Current Drag Forces Mooring Pattern Elasticity of Lines General Mooring Guidelines Operational Considerations Terminal Mooring System Management Operating Limits 18 Operating Guidelines / Mooring Limits 18 Joint Terminal/Ship Meeting and Inspection 22 instrumented Mooring Hooks or Visual Inspection of Mooring Lines Ship Mooring Management Line Tending Emergency and Excessively High Mooring Load Conditions Limitations on the Use of Tugs and Boats General Recommendations Recommendations for Berth Designers 26 Recommendations for Terminal Operators 26 Recommendations for Ship Designers 27 Recommendations for Ship Operators 27 2 Mooring Restraint and Environmental Criteria General Considerations Standard Environmental Criteria Calculation of Forces Mooring Restraint Requirements Basic Principles of Mooring Calculations Standard Restraint Requirements Site-Specific Environmental Data and Mooring Line Loads Most Probable Maximum (MPM)