MSN 1781 (Amendment 2) The merchant shipping regulations 1996: COLREG (link)
This Notice and the Rules referred to in it are an integral part of the UK Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996. Those Regulations implement the IMO Convention on the International Regulations for Preventing Collisions at Sea, 1972 (COLREG). They enhance safe navigation by prescribing the conduct of vessels underway, specify the display of internationally understood lights and sound signals and set out collision avoidance actions in close quarter situations.
This newly amended Merchant Shipping Notice outlines changes made to COLREG. These changes, in force from 1 January 2016, include a new Part F, containing three Rules, Rule 39, 40 and 41, which provide for IMO verification of Member States’ compliance with the provisions of the COLREG convention.
The notice supersedes ‘MSN 1781’, ‘MSN 1781 Corrigendum’ and ‘MSN 1781 Amendment 1’ which have been revoked.
Source: MCA