PLNTM 005 Submarine Movements and Operations in the Dockyard Port Direction


King's Harbour Master Plymouth

LNTM No 005/22




1. Paragraphs 2 & 5(b) of this notice are directions by the Queens Harbour Master Plymouth in exercising powers conferred by the Dockyard Port of Plymouth Order 2020.

2. “D” buoy is the primary submarine berth in the Sound. However, when operationally necessary, “E” buoy may also be used by submarines. No merchant or other private vessel shall navigate within 100 metres of a submarine secured to “D” or “E” buoy.

3. Mariners are warned that submarines may well remain indistinct at night, especially when viewed from seaward. Longroom Port Control Station may also alert vessels transiting the Sound to the presence of submarines.

4. Additional Signals Displayed During the Movement of Nuclear Powered Submarines:

a. Nuclear powered submarines are constrained by their draught to navigate only in the deep-water channels of the Dockyard Port. Due to their special construction they are unable to display the signals prescribed for vessels constrained by their draught in Rule 28 of the International Regulations for Preventing Collisions at Sea 1972.

b. These signals will therefore be displayed by the tugs accompanying nuclear submarines while transiting the harbour, and are as follows:

(1) By day a black cylinder.

(2) By night three all round red lights in a vertical line.

5. Submarine Operations:

a. Submarines regularly operate in Plymouth Sound and approaches with equipment deployed astern, extending out to 800 metres. Although this equipment is negatively buoyant, it can rise to the surface.

b. Whilst underway within the Dockyard Port of Plymouth, a moving exclusion zone will be in force in accordance with PLNTM 04/22. Additionally vessels should avoid crossing astern within 800m of a submarine approaching the port and when a submarine is conducting towed array operations within Plymouth Sound. If in doubt mariners should contact the submarine direct on VHF Channel 14 to seek advice. If radio contact with the submarine cannot be established, vessels should call Longroom Port Control Station for direction.

1st January 2022

Saturday 01 Jan 2022