ISO 13729:2012

Ships and marine technology - Ship's mooring and towing fittings - Closed chocks

1 Scope This International Standard specifies the design, size and technical requirements for closed chocks installed to lead the mooring and towing rope of a ship.

Navires et technologie maritime — Corps-morts et ferrures de remorquage de navires — Chaumards fermés

General Information

• Status: Withdrawn
• Publication Date: 24-Jun-2012
• Withdrawal Date: 24-Jun-2012
• ICS: 47.020.50 - Deck equipment and installations
• Technical Committee: ISO/TC 8/SC 4 - Outfitting and deck machinery
• Drafting Committee: ISO/TC 8/SC 4 - Outfitting and deck machinery
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 28-Aug-2020
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 13729:2020 - Ships and marine technology - Ship's mooring and towing fittings - Closed chocks
• Effective Date: 30-Sep-2017

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 13729
First edition
2012-07-01
Ships and marine technology — Ship’s
mooring and towing fittings — Closed
chocks
Navires et technologie maritime — Corps-morts et ferrures de
remorquage de navires — Chaumards fermés
Reference number
©
ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland
ii © ISO 2012 – All rights reserved

Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification . 1
4.1 Type . 1
4.2 Nominal sizes . 1
5 Dimensions . 1
6 Materials . 2
7 Construction . 2
8 Manufacturing and inspection . 2
9 Marking . 2
Annex A (informative) Basis for strength assessment of closed chocks . 7
Bibliography .10
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 13729 was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
SC 4, Outfitting and deck machinery.
iv © ISO 2012 – All rights reserved

Introduction
The closed chock is a type of ship’s mooring and towing fitting installed on the shipside to lead the mooring and
towing rope from the ship’s inboard to outboard.
The closed chocks are normally adopted for ships which use wire ropes. The radius of chock surface was designed
based on the bending ratio of rope through the chock of not less than twelve times of the wire rope diameter.
INTERNATIONAL STANDARD ISO 13729:2012(E)
Ships and marine technology — Ship’s mooring and towing
fittings — Closed chocks
1 Scope
This International Standard specifies the design, size and technical requirements for closed chocks installed to
lead the mooring and towing rope of a ship.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
IMO Circular MSC/Circ.1175, Guidance on shipboard towing and mooring equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
safe working load
SWL
maximum load in kN on the rope that should normally be applied in service conditions
4 Classification
4.1 Type
The closed chock is to be classified by its installation site as follows:
— Type A – Deck-mounted closed chock;
— Type B – Bulwark-mounted closed chock.
4.2 Nominal sizes
The nominal sizes, L x H x D of closed chocks are denoted by reference to the width and height of the opening
and depth of the chock in millimetres. For the closed chocks having the same size, the alphabetical character
is followed by nominal size for the different SWL.
The nominal sizes are:
250x200x214, 300x250x286, 350x250x333, 400x250x381, 450x250x381, 500x250x381, 400x250x428,
450x250x428, 500x250x428, 500x400x428, 500x250x525A, 500x400x525A, 500x250x525B, 500x400x525B
5 Dimensions
Closed chocks have dimensions and particulars in accordance with Tables 1 and 2, and Figures 1 and 2.
6 Materials
The following material is to be used for manufacturing the closed chocks:
— Chock: steel casting material having a yield point of not less than 235 N/mm or equivalent.
The carbon contents of the steel casting shall not be more than 0,23 % considering weldability.
7 Construction
The foundation of the closed chocks shall be determined by considering the actual load direction. The foundation
and welding connections to the hull shall be guaranteed reliable transmission of the maximum loading of the
closed chocks to hull construction without any plastic deformation or cracks.
8 Manufacturing and inspection
8.1 All surfaces of the closed chocks including welding shall be free from any visible flaws or imperfections.
8.2 All surfaces in contact with the ropes shall be free from surface roughness or irregularities likely to cause
damage to the ropes by abrasion.
8.3 The closed chocks shall be coated externally with an anti-corrosion protective finish.
9 Marking
9.1 The SWL intended for the use of the closed chocks shall be noted in the towing and mooring plan
available on board for the guidance of the shipmaster, as specified in MSC/Circ.1175.
9.2 The actual SWL on board shall be determined by considering the foundation and under deck reinforcement,
and it shall be marked on the towing and mooring plan. The actual SWL shall not be over the SWL indicated in
this International Standard.
9.3 The closed chocks shall be clearly marked with their SWL by weld bead or equivalent. The SWL shall be
expressed in tonnes (letter ‘t’) and be placed so that it is not obscured during operation of the fitting
...