ISO 23116:2020

Ships and marine technology - Ship’s mooring and towing fittings - Seats for Panama chocks

This document specifies the types, nominal sizes, dimensions and materials, as well as construction, manufacturing and marking requirements, for the seats for Panama chocks installed to lead the mooring and towing rope of a ship. It is applicable to ships passing through the Panama Canal, which are normally assisted by locomotives using steel towing wires and/or by tug boats. These seats for chocks meet normal mooring requirements and Panama Canal requirements. NOTE The seat for Panama chocks (SWL of 90 tons) for Panamax Plus and Neopanamax vessels can be replaced by seats for closed chocks (see ISO 23113).

Navires et technologie maritime — Corps-morts et ferrures de remorquage de navires — Sièges pour écubiers de Panama

General Information

• Status: Published
• Publication Date: 27-Aug-2020
• 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/WG 4 - Ship's mooring and towing fittings
• Current Stage: 9060 - Close of review
• Completion Date: 04-Mar-2031

Overview

ISO 23116:2020 - Ships and marine technology - Ship’s mooring and towing fittings - Seats for Panama chocks - specifies the types, nominal sizes, dimensions, materials, construction, manufacturing, inspection and marking requirements for seats used to lead mooring and towing ropes through Panama chocks. It is intended for ships transiting the Panama Canal (locomotive-assisted or tug-assisted operations) and aligns seat design with normal mooring and Panama Canal requirements. The standard also notes alternatives for Panamax Plus / Neopanamax installations (see ISO 23113).

Key topics and technical requirements

• Types and sizes: Defines three installation types - Type A (deck-mounted), Type B (deck and side shell-mounted) and Type C (bulwark/brackets). Nominal opening widths are 310 mm and 360 mm with dimensional tables and figures.
• Materials: Requires weldable steel plates with yield strength ≥ 235 N/mm².
• Construction & foundation: Foundations must be designed for actual load directions so loads transmit to hull structure without plastic deformation or cracking.
• Manufacturing & inspection:
  • All surfaces (including welds) must be free from visible flaws.
  • Rope-contact surfaces must be smooth to avoid abrasion.
  • External anti‑corrosion coating is required.
• Marking & documentation:
  • Safe Working Load (SWL) must be marked on the fitting (in tonnes) and recorded on the ship’s towing and mooring plan as per IMO MSC/Circ.1175.
  • The actual on‑board SWL must account for under‑deck reinforcement and shall not exceed values indicated in the standard.
• Strength assessment:
  • Strength evaluation by finite element analysis (FEM) is described in Annex A.
  • Loading cases include horizontal and vertical loads (treated individually).
  • Combined stress under SWL limited to 85% of material yield.
• Reference values: The standard includes example SWL and dimensional tables (for guidance only); final SWL is to be agreed between manufacturer and shipowner based on installation.

Applications and users

ISO 23116:2020 is used by:

• Shipbuilders and naval architects designing mooring arrangements for Panama transits
• Manufacturers of Panama chocks and seats
• Classification societies, flag administrations and port authorities reviewing compliance
• Ship operators and shipmasters referencing SWL on towing/mooring plans
• Marine surveyors and maintenance teams inspecting fittings

Practical uses include selecting correct seat type and size, specifying material and welding, verifying FEM strength checks, ensuring rope protection and corrosion protection, and documenting SWL for safe mooring/towing operations.

Related standards

• ISO 13728 - Panama chocks
• ISO 23113 - Closed chocks (alternative for larger vessels)
• IMO MSC/Circ.1175 - Guidance on shipboard towing and mooring equipment
• IACS UR A2 and OCIMF MEG4 - industry mooring guidelines

Keywords: ISO 23116:2020, Panama chocks, seats for Panama chocks, ship’s mooring and towing fittings, SWL, Panama Canal, mooring equipment, finite element analysis.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 23116
First edition
2020-08
Ships and marine technology — Ship’s
mooring and towing fittings — Seats
for Panama chocks
Navires et technologie maritime — Corps-morts et ferrures de
remorquage de navires — Sièges pour écubiers de Panama
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – 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 . 2
5 Dimensions . 2
6 Materials . 2
7 Construction . 2
8 Manufacturing and inspection . 2
9 Marking . 2
Annex A (normative) Basis for strength assessment of the seats for Panama chocks .9
Bibliography .14
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www .iso .org/ iso/ foreword .html.
This document was prepared Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
SC 4, Outfitting and deck machinery.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
The seat for Panama chocks is a seat 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.
INTERNATIONAL STANDARD ISO 23116:2020(E)
Ships and marine technology — Ship’s mooring and towing
fittings — Seats for Panama chocks
1 Scope
This document specifies the types, nominal sizes, dimensions and materials, as well as construction,
manufacturing and marking requirements, for the seats for Panama chocks installed to lead the
mooring and towing rope of a ship. It is applicable to ships passing through the Panama Canal, which
are normally assisted by locomotives using steel towing wires and/or by tug boats. These seats for
chocks meet normal mooring requirements and Panama Canal requirements.
NOTE The seat for Panama chocks (SWL of 90 tons) for Panamax Plus and Neopanamax vessels can be
replaced by seats for closed chocks (see ISO 23113).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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
Panama Canal Requirements — OP Notice to shipping No. N-1-2018 — Vessel requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
safe working load
SWL
safe load limit (maximum permissible load) of the fittings used for mooring and towing
4 Classification
4.1 Type
The seat for Panama chocks shall be classified by its installation site as belonging to one of the
following types:
a) Type A: seat for deck-mounted Panama chock;
b) Type B: seat for deck and side shell-mounted Panama chock;
c) Type C: brackets for bulwark-mounted Panama chock.
4.2 Nominal sizes
The nominal sizes of the seats for the Panama chocks are denoted by reference to the width of the
opening, in millimetres.
The nominal sizes are 310 and 360.
5 Dimensions
The seats for Panama chocks shall have dimensions and particulars in accordance with Tables 1, 2 and
3, and Figures 1, 2 and 3.
6 Materials
Weldable steel plates having a yield point of not less than 235 N/mm shall be used for manufacturing
the seats for mooring chocks.
7 Construction
The foundation of the Panama chocks shall be determined by considering
...