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KHM Portsmouth



King’s Harbour Master Portsmouth

LNTM 10/24

1. NOTICE IS HEREBY GIVEN jointly by the King's Harbour Master Portsmouth and the Harbour Master ABP Southampton, that swimming across The Solent should not be undertaken without considerable preparation and very careful assessment of the risks. The cross-Solent swimmer has to cross at least one busy shipping lane, taking into account fast moving ferries and hovercraft travelling to and from the Isle of Wight, some of the largest vessels in the world transiting the deep-water channel and the many recreational craft that use the area. In addition, tidal streams within the Solent are significant at times and must be carefully factored into any risk assessment.  

2. Before any swim can be undertaken, those authorities responsible for safety on the water and for coordination of the passage of commercial vessels through the Solent need to be informed as early in the planning stage as possible. Principally, these are KHM Portsmouth, who is statutorily responsible for most of the waters of the eastern Solent, ABP Southampton who operates the Vessel Traffic Service (VTS – call sign Southampton VTS) for the area and Solent Coastguard, which co-ordinates search and rescue resources within the area. Route selection is vitally important and should be tailored to the size of the group and the ability of the slowest swimmer. 

3. To comply with the Port Marine Safety Code and with the Safety Management Systems of the Dockyard Port of Portsmouth and ABP Southampton, organisers of recreational and charity events planned to take place in the Solent are responsible for the safety of their event and for the detailed planning required to achieve the successful completion of the event. 

4. This responsibility includes the undertaking of a detailed Risk Assessment for the event. Help with this can be found in ABP Southampton Notices to Mariners ( and KHM Portsmouth’s LNTM 03/24

5. To assist with the planning of your event a set of updated guidelines for cross Solent swims has been prepared and can be viewed at:

6. In 2023 the guidelines were updated to remind organisers that the event is not a race, but a crossing and includes specific detail on the following: 

Swimmer spread, that there will not be more than 100 metres between first and last swimmer in a group of swimmers.
Operating as a commercial venture, to ensure commercial coded vessels and commercially endorsed crew are used.
Proof of Insurance, and the submission of emergency and communication plans to be included with the risk assessment.

7. Once completed, a copy of the Event Risk Assessment is to be emailed to the King’s Harbour Master Portsmouth ([email protected]), HM Coastguard  (zone [email protected]) and ABP Southampton ([email protected]).  It is obligatory on the swim organiser to notify, in writing, the above authorities at least 28 days ahead of the event, that a swim is planned. With less than 28 days notice, the publication of required Local Notices to Mariners and review of the plan and risk assessment may not be achievable. This could therefore result in the harbour authorities recommending that the event does not take place.   

8. Portsmouth LNTM 35/23 is hereby superseded.


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