SPM_Guide_e ABS

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Guide for the Mooring of Oil Carriers at Single Point Moorings

GUIDE FOR

THE MOORING OF OIL CARRIERS AT SINGLE POINT

MOORINGS

DECEMBER 2010

American Bureau of Shipping

Incorporated by Act of Legislature of the State of New York 1862

American Bureau of Shipping ABS Plaza

16855 Northchase Drive Houston, TX 77060 USA

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Foreword

Foreword

This Guide has been developed in response to industry requests for an optional ABS Class notation to address arrangements where an Oil Carrier is fitted with equipment enabling it to be moored to single point moorings.

The requirements cover the parts of OCIMF (Oil Companies International Marine Forum) “Recommendations for Equipment Employed in the Bow Mooring of Conventional Tankers at Single Point Moorings” 4th edition May 2007 applicable for the vessel as per IACS Recommendation 13 [(1984), Rev 1, July 2004] “Standards for Ship Equipment for Mooring at Single Point Moorings”

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ABSGUIDE FOR THE MOORING OF OIL CARRIERS AT SINGLE POINT MOORINGS

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2010 iii Table of Contents

GUIDE FOR

THE MOORING OF OIL CARRIERS AT SINGLE POINT

MOORINGS

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2010 1 Section 1: General

S E C T I O N

1 General

1 Application

This Guide is applicable to conventional Oil Carriers fitted with equipment enabling them to be moored by the bow to single point moorings or moored in tandem to FPSO/FSO terminals. The application of this Guide to other types of tankers will be subject to special consideration.

3 Notation

An Oil Carrier provided with mooring arrangements in accordance with the requirements of this Guide will be eligible to be assigned the Class Notation SPMA.

5 Submission of Design Plans and Data

The following design plans and data are to be submitted:

• Plan showing the mooring arrangement with position of bow fairleads, bow chain stoppers, winches and capstans and pedestal rollers and winch storage drums, if applicable

• Details of bow chain stoppers

• Details of bow fairleads and their attachment to the bulwark

• Details of attachment to deck and supporting structure of the bow chain stoppers, winch or capstans and pedestal rollers and winch storage drums, if applicable.

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Section 2: Arrangements

S E C T I O N

2 Arrangements

1 General

The vessel is to be fitted with bow chain stoppers and bow fairleads as per Section 2, Table 1. Additional pedestal roller fairleads may be required for alignment purposes and a winch or capstan for the pick-up rope. The requirements for the supporting deck structure in way of all equipment are to be in accordance with 3-2-7/4, 3-5-1/11, and 3-5-1/15 of the ABS Rules for Building and Classing Steel Vessels (Steel Vessel Rules).

TABLE 1

Required Arrangements by Vessel Deadweight

Ship Size

(tonnes DWT at maximum summer draught) Chafing Chain Size Number of Bow Chain Stoppers Minimum SWL (Tonnes) Number of Bow Fairleads

(recommended)

100,000 or less

(See Note) 76 mm (3 in.) 1 200 (440405 lbs) tonnes 1

Over 100,000 but not greater than 150,000 (See Note) 76 mm (3 in.) 1 250 (550505 lbs) 1 Over 150,000 76 mm (3 in.) 2 350 (770707 lbs) 2

Note: Ships in this size range may elect to fit two stoppers / fairleads to ensure full range terminal acceptance

3 Bow Chain Stoppers

3.1 Number, Chain Cable Size, and Minimum SWL

The number, chain cable size, and minimum SWL of bow chain stoppers are to be in accordance with Section 2, Table 1. The chain stoppers are to be permanently marked with the SWL to which they have been designed and tested.

3.3 Location

Bow chain stoppers are to be located between 2.7 m (8 ft 101_/₄_{in.) and 3.7 m (12 ft 1}3_/₄_{in.) aft of the bow} fairlead.

3.5 Alignment

Stoppers are to be positioned to give correct alignment with the bow fairlead and the pedestal fairlead or storage drum of the winch.

3.7 Securing

A standard 76 mm (3 in.) stud-link chain is to be secured when the chain engaging pawl or bar is in the closed position. When in open position, the chain and associated fittings are to be allowed to pass freely.

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Section 2 Arrangements

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2010 3

3.9 Structural Strength

The structural strength of the stopper and supporting structure is to be in accordance with 3-5-1/11 of the Steel Vessel Rules, when applying a load equal to the SWL given in Section 2, Table 1.

3.11 Relation to Deck Structure

Stoppers are to be fitted as close as possible to the deck structure, taking due consideration to possible obstacles in order to obtain a free lead through the fairleads.

3.13 Fairing of Leading Edge

The leading edge of the bow chain stopper base is to be faired to allow for the unimpeded entry of the chafing chain.

3.15 Testing

Upon installation, bow stoppers are to be load tested to the equivalent SWL in the presence of our surveyor and a test certificate is to be issued. The test certificate is to be available for inspection onboard the ship. Applicable strength of the supporting structure is to be documented by adequate analyses and submitted for review to a technical office. A copy of the approval letter in such cases is to be available onboard.

5 Bow

Fairleads

5.1 Openings

Bow fairlead openings are to measure at least 600 mm × 450 mm. (231_/₂ in. × 173_/₄_in.)

5.3 Ships with Two Fairleads

For ships fitted with two fairleads, they are to be spaced, from center to center, at least 2.0 m (6 ft 63_/₄_in.) apart. In any event, the fairleads are not to be spaced more than 3.0 m (9 ft 10 in.) apart.

5.5 Ships with One Fairlead

For ships fitted with one fairlead, it is to be positioned on the centerline.

5.7 Shape

Fairleads are to be oval or round in shape and adequately faired when fitted in order to prevent chafing chains from fouling on the lower lip when heaving inboard. Square fairleads are not suitable.

5.9 Number of Fairleads

When two bow chain stoppers are fitted, then two bow fairleads are required.

The structural strength of the bow fairlead is to be based on a safety factor of 2.0 against the yield criterion when applying a load equal to SWL given in Section 2, Table 1.

7 Pedestal

Rollers

7.1 Position

Winches or capstans are to be positioned to enable a direct pull to be achieved on the continuation of the direct lead line between the bow fairleads and bow stoppers. Alternatively, a pedestal roller may be positioned between the stopper and the winch or the capstan, in order to achieve direct pull.

7.3 Distance between the Bow Stoppers and Pedestal Roller

The distance between the bow stoppers and pedestal roller is to be considered so that an unrestricted line pull is achieved from the bow fairlead and through the bow stopper.

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Section 2 Arrangements

7.5 Number and Angle

The number of pedestal rollers used for each bow chain stopper is not to exceed two and the angle of change of direction of the pick-up rope lead is to be minimal.

The structural strength of the pedestal rollers and supporting structure is to be in accordance with 3-5-1/15 of the Steel Vessel Rules when applying a load equal to the SWL given in Section 2, Table 1.

9 Winches

or

Capstans

Winches or capstans are to be capable of exerting a continuous duty pull of not less than 15 tonnes (33030 lbs).

11 Winch Storage Drum

If a winch storage drum is used to stow the pick-up rope, it is to be of sufficient size to accommodate 150 m (492 ft) of 80 mm (33_/₁₆_{in.) diameter rope.}

13 Materials

Material for the hull structure is to be in accordance with Chapter 1 of the ABS Rules for Materials and Welding (Part 2). Material for the deck fittings will be accepted on the basis of the manufacturer’s certified mill test reports.

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2010 5 Section 3: Survey Requirements

S E C T I O N

3 Survey Requirements

1 Annual

Surveys

Chain stoppers and fairleads, including foundations, are to be examined.

3 Special Periodical Surveys

Chain stoppers, fairleads, winches, capstans, and other deck fittings, including all foundations, are to be examined and operationally tested.

SPM_Guide_e ABS

GUIDE FOR

THE MOORING OF OIL CARRIERS AT SINGLE POINT

MOORINGS

DECEMBER 2010

Foreword

.

GUIDE FOR

THE MOORING OF OIL CARRIERS AT SINGLE POINT

MOORINGS

CONTENTS

.

1 General

1 Application

3 Notation

5

Submission of Design Plans and Data

2 Arrangements

1 General

TABLE 1

Required Arrangements by Vessel Deadweight

3

Bow Chain Stoppers

.

5 Bow

Fairleads

7 Pedestal

Rollers

9 Winches

or

Capstans

11 Winch Storage Drum

13 Materials

.

3 Survey Requirements

1 Annual

Surveys

3

Special Periodical Surveys