Skip to content
Recruiting now.Explore navy careers

KHM Portsmouth



King’s Harbour Master Portsmouth

LNTM 07/24

1. NOTICE IS HEREBY GIVEN by the King’s Harbour Master Portsmouth that, within Portsmouth Naval Base, tugs frequently move warships, Royal Fleet Auxiliaries (RFAs) and other craft when they have no operational engine or steering capability of their own in what is known as a “Cold Move”.  When this occurs, wherever possible, the following navigation lights and signals from the International Regulations for Preventing Collisions at Sea (hereafter referred to as the “Rules”) are to be shown by vessels involved:

a. Vessels being moved:   Exhibit the lights or shapes at Rule 24e (by night, sidelights and sternlight, and by day a diamond shape if the tow exceeds 200 metres). The use of “Not Under Command” signals (Rule 27a) by the vessel being moved are not appropriate and are not to be exhibited.

b. Tugs or other towing vessels conducting the move: Exhibit the lights or shapes at Rules 24a and 24c (by night, sidelights, sternlight and towing lights, and by day a diamond shape if the tow exceeds 200 metres).

2. Cold Moves within the Naval Base will not normally be treated as a “composite unit” or a “group” and thus the lights at Rules 24b and 24f will not be applicable.

3. If in the opinion of the Pilot in charge, a Cold Move severely restricts the towing vessel(s) and tow in their ability to deviate from their course (Rules 3g(vi) and 27c), then the towing vessels shall exhibit the signals at Rules 27b(i) and 27b(ii) (By night a red light over a white light over a red light vertically, and by day a ball over a diamond over a ball vertically).

4. In the event that a “dead” vessel is moved by night, it may not be possible for it to show the lights at Rule 24e (see Paragraph 1a above). In this case the towing vessels will make every effort to warn other Harbour users in the vicinity by whatever other means are appropriate.

5. Portsmouth LNTM 07/23 is hereby superseded.


Monday 01 Jan 2024

King's Harbour Master

Owners, Agents, Charterers, Marinas, Yacht Clubs and Recreational Sailing Organisations should ensure that the contents of this Notice are made known to the masters or persons in charge of their vessels or craft.

Stay informed

To receive Notices and/or Shipping Movements, please make your selection below.

Follow KHM Portsmouth on X