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KHM Portsmouth



King’s Harbour Master Portsmouth

LNTM 31/24

1. NOTICE IS HEREBY GIVEN by the King’s Harbour Master Portsmouth that Autonomous Surface Vessel trials will be conducted in the Hayling Bay or Ryde Middle areas during the period 12 February 2024 to 15 March 2024.

2.  Autonomous Surface Vessel (ASV) operations will be conducted in daylight only with a safety vessel in attendance throughout. An ASV “P38 Aggressor” will be undertaking Sea Trials in the Hayling Bay or Ryde Middle area (weather dependant). P38 Aggressor is a 13 metre craft, is coloured black and has a top speed of 25 knots. P38 Aggressor will be accompanied by Valkyrie 6 or Bossy Boots for autonomous trials and SB850 for Uncrewed Trials which will act as safety vessels for the sea trial.  The trial staff operators embarked on the safety boat will intervene in the event of any safety issues. For the trials serials, P38 Aggressor will be remotely/autonomously controlled, with the operator following the International Rules for Preventing Collisions at Sea (COLREGS) at all times.

P38 Aggressor

Valkyrie 6 (Bossy Boots Sister Vessel)


3. Trials will take place from approximately 1000 to 1600 during the day in one of the trials areas of Hayling Bay or Ryde Middle as shown below. P38 Aggressor will only be operated in remote/autonomous mode when in the trials areas and when the trial staff manning the safety boat have verified that the proposed sea trial is safe to continue.

The trials areas are shown below within the pink boxed area. 

Hayling Bay area: 

50 °45.746’N  001° 3.023’W
50° 45.814’N  000° 58.016’W
50° 44.769’N  000° 57.999’W
50° 44.914’N  001° 3.030’W

Hayling Bay trials area (Chart not to be used for navigation)

Ryde Middle Area:

50° 46.700'N  1° 14.800'W
50° 46.300'N  1° 13.000'W
50° 45.900'N  1° 13.200'W
50° 46.300'N  1° 15.000'W

Ryde Middle trials area (Chart not to be used for Navigation)

4. The assigned safety vessels will be listening on VHF Ch 11, 12, 72 and 16. Where possible, trials vessels will maintain a minimum 200-metre separation from other craft, and trial runs will be modified or aborted if a close-quarters situation is developing. 

5. All trials vessels will obey the International Rules for Preventing Collisions at Sea (COLREGS) at all times. 

6. Cancel this LNTM on 16 March 2024.


Thursday 08 Feb 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.

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