Regulation 4 - Navigational Warnings


  • Contracting Governments are required to promulgate all dangers to navigation.
Regulation 4
Each Contracting Government shall take all steps necessary to ensure that, when intelligence of any dangers is received from whatever reliable source, it shall be promptly brought to the knowledge of those concerned and communicated to other interested Governments.*

* Refer to the Guidance on the IMO/IHO World-Wide Navigational Warning Service adopted by the Organization by resolution A.706(17), as amended.

MCA Guidance
1. Regulation 4 obliges Contracting Governments to promulgate information relating to any type of danger received from any reliable source.
2. Mariners should refer to Regulations 31 and 32 which lay down the masters' obligations to report dangers to navigation (Reg. 31) and provide the correct reporting format (Reg. 32.) (see also 4 below).
3. Navigational warnings are promulgated in the UK under a Memorandum of Understanding between the MCA and the UK Hydrographic Office (UKHO). The service meets the requirements of Regulation 4 as well as IMO Resolution A.706(17) which implements the Worldwide Navigational Warning Service (WWNWS) The UKHO acts as the "national co-ordinator" for the UK in collating and issuing coastal warnings and acts as "NAVAREA coordinator" for Area 1.

Mariners are requested to inform the UKHO immediately when new dangers or changes / defects in aids to navigation are identified. Full contact details and instructions, together with copies of the UKHO reporting form (Hydrographic Note) are provided in the weekly copy of the Admiralty Notices to Mariners.

Contact points for navigational information are:

Urgent navigational information - e-mail:

Other navigational information - e-mail: or

Fax: +44(0)1823 322352

Phone: +44 (0)1823 353448


IMO Resolution A.706(17) (as amended) - Guidelines on the IMO/IHO Worldwide Navigation Warning Service,

Details of the WWNWS are given in the UKHO Annual Notice to Mariners no.13

Notices to Mariners:
Fax: +44(0)1823 322352
Tel:  +44(0)1823 723315


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