Regulation 21 - International Code of Signals and IAMSAR Manual


  • All ships which are required to carry radio installations to carry International Code of Signals.

  • All ships (see Guidance note 2) to carry Volume III of the IAMSAR Manual.
Regulation 21

1. All ships which, in accordance with the present Convention, are required to carry a radio installation shall carry the International Code of Signals as may be amended by the Organization. The Code shall also be carried by any other ship which, in the opinion of the Administration, has a need to use it.

2. All ships shall carry an up-to-date copy of Volume III of the International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual.


MCA Guidance
1. INTERNATIONAL CODE OF SIGNALS - All passenger ships, and all cargo ships of 300 GT and over, when engaged on international voyages, are required to carry the International Code of Signals.

IAMSAR MANUAL VOL.III* - Regulation 1 permits Administrations some flexibility on the extent to which Regulation 21 applies to certain classes of ships. Accordingly for UK ships the requirement to carry Volume III of the IAMSAR manual does not apply to:
             - ships below 150 gt on any voyage
             - ships below 500 gt not engaged on international voyages, and
- fishing vessels

The IAMSAR manual must be kept up to date when amendments are issued by the IMO.

3. Both these documents are published by the IMO, available from IMO Publications. See

*The requirement to carry Volume III of the IAMSAR Manual came into force on 1 January 2004
[IMO Resolution MSC 123(75)]


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