ISO/TR 9814:2025

Ships and marine technology — Good practices of preventing capsizing during turning of ships with large profile height

This document gives good practices on how to prevent the capsizing of ships with large profile height during turning. The following are covered this document: a) ship turning, centrifugal force, and consequent heeling; b) accident use cases of capsizing during turning; c) effect of the KG on the ship stability; d) three good practices of preventing capsizing during turning of ships.

Navires et technologie maritime — Bonnes pratiques de prévention du chavirement lors du virage des navires à grande hauteur de profil

General Information

• Status: Published
• Publication Date: 15-Jun-2025
• ICS: 47.020.01 - General standards related to shipbuilding and marine structures
• Technical Committee: ISO/TC 8/SC 8 - Ship design
• Drafting Committee: ISO/TC 8/SC 8 - Ship design
• Current Stage: 6060 - International Standard published
• Start Date: 16-Jun-2025
• Due Date: 21-May-2025
• Completion Date: 16-Jun-2025

Standards Content (Sample)

Technical
Report
ISO/TR 9814
First edition
Ships and marine technology —
2025-06
Good practices of preventing
capsizing during turning of ships
with large profile height
Navires et technologie maritime — Bonnes pratiques de
prévention du chavirement lors du virage des navires à grande
hauteur de profil
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 2
5 Analysis of capsize accidents of five ships . 3
5.1 General .3
5.2 Ship categories based on cargo space requirements .4
5.2.1 Weight carrier .4
5.2.2 Volume carrier .4
5.2.3 Area carrier .4
5.3 Analysis of capsize accidents .4
5.3.1 General .4
5.3.2 Similarities.4
5.3.3 Differences .5
6 Effect of KG on the GZ curve . 5
6.1 KG and its role in capsizing accidents .5
6.2 Characteristics of hull form and GZ curves .9
6.2.1 General .9
6.2.2 Hull forms with two inflection points along the GZ curve .9
7 Three good practices to prevent capsizing during turning of ships .10
7.1 General .10
7.2 Semi-automatic inclining tests before loaded departure .10
7.2.1 General .10
7.2.2 Features of inclining test before departure .11
7.2.3 Stability screening without inclining test . 12
7.3 Maximum heeling angle while turning .14
7.3.1 General .14
7.3.2 Maritime autonomous surface ships . 15
7.3.3 Considerations on cargo slippage.16
7.4 Precise calculation of free surface moment (FSM) .17
7.4.1 Slack limit of NAPA software .17
7.4.2 FSM at 98 % filling level .17
7.4.3 Improvement of stability calculation software .18
Annex A (informative) Cases of capsizing accidents . 19
Annex B (informative) Additional information on ship features .28
Bibliography .30

iii
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,
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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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
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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 is prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee SC
8, Ship design.
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
Introduction
There are many similarities between the following ship accidents: the Golden Ray in 2019, the Hoegh Osaka
in 2015, the Sewol ferry in 2014, the Crown Princess in 2006 and the Queen Hind in 2019. By comparing
and analysing the causes of these five accidents, identifying similarities between them, and generalizing the
findings, this document aims to help prevent similar accidents from occurring in the future.
Based on the analysis of the five ship accidents and a similar land truck accident, this document describes
three good practices to prevent similar accidents from recurring. Since similar accidents can occur not only
in old ships but also in the new ships, additional measures are described, as similar accidents can occur
again unless these points are corrected.

v
Technical Report ISO/TR 9814:2025(en)
Ships and marine technology — Good practices of preventing
capsizing during turning of ships with large profile height
1 Scope
This document gives good practices on how to prevent the capsizing of ships with large profile height during
turning.
The following are covered this document:
a) ship turning, centrifugal force, and consequent heeling;
b) accident use cases of capsizing during turning;
c) effect of the KG on the ship stability;
d) three good practices of preventing capsizing during turning of ships.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
capsize
to (cause a boat or ship to) turn upside down by accident while on water
3.2
fishtailing
to cause the tail of an aircraft or the back of a motor car to swing from side to side
3.3
free surface effect
mechanism which can cause a watercraft to become unstable and capsize (3.1)
Note 1 to entry: It refers to the tendency of liquids to move in response to changes in the attitude of a craft's cargo
holds or liquid tanks.
3.4
inclining test
test performed on a ship to determine its stability, lightship weight and the coordinates of its centre of gravity

3.5
integrated monitoring, alarm, and control system
IMACS
computer-based system used for monitoring and controlling various processes in industries such as oil and
gas, power generation, water treatment, and manufacturing
3.6
maritime autonomous surface ship
MASS
increased automation on board ships, which could ultimately reach full autonomy or become a remotely
controlled unmanned vessel
3.7
overturn
single-vehicle accident event in which the vehicle rolls at least 90°
[SOURCE: ISO 6813:1998, 3.2.1, modified — note 1 to entry has been removed.]
3.8
profile height
distance from the waterline to the high point on the ship's structure or cargo, such as a stack of containers
or superstructure which continues more than about 70 % of the ship length
Note 1 to entry: This term is distinct from "air draft", which refers to the height used to assess whether a vessel can
pass beneath a bridge. In contrast, profile height is introduced in this document to specify the height influencing the
vessel's stability. While related to the wind pressure area (3.10), profile height represents a different concept.
3.9
weigh station
facility near a road where vehicles, esp
...