Also known as: HMS A1, A1 submarine, Holland A1
Lying in just 12 metres of water off Bracklesham Bay, HMS A1 holds a unique place in British naval history: she was the very first submarine designed and built in this country for the Royal Navy. Constructed by Vickers in 1903, she had already survived one sinking — a collision with SS Berwick Castle in 1904 that killed eleven crew before she was raised — when she was repurposed as an unmanned torpedo target. In August 1911, operating on automatic pilot, she sank for good off Selsey Bill. Tidal currents slowly dragged her five miles along the seabed to her present position. The hull is virtually intact, with the bow standing proud while the stern disappears beneath a sandbank. Protected under the Protection of Wrecks Act since 1998, she requires a permit to dive, and the Nautical Archaeology Society has established a structured dive trail for visiting divers. For anyone interested in submarine heritage, there is no more historically significant shallow dive in British waters.
Used as an unmanned target during torpedo trials. Sank while operating under automatic pilot off Selsey Bill. Tidal currents later moved the wreck approximately 5 miles to Bracklesham Bay. This was the first British-designed and built submarine in Royal Navy service; she had previously sunk in March 1904 (collision with SS Berwick Castle, 11 crew lost) and was raised.
HMS/m A1 is a submarine wreck located off West Sussex, United Kingdom at a depth of 12 metres. The vessel was lost due to foundering in 1911. The wreck is diveable.
HMS/m A1 lies at approximately 12 metres depth, Bracklesham Bay, near East Wittering, West Sussex (originally sank off Selsey Bill).
HMS/m A1 foundered on 1 August 1911, off West Sussex, United Kingdom. 0 people lost their lives.
Diving the HMS/m A1 is rated beginner and is suitable for newly certified Open Water divers. Minimum certification: PADI Open Water / BSAC Ocean Diver. Recommended: PADI Open Water / BSAC Ocean Diver.
The best months to dive HMS/m A1 are May, June, July, August, September. Water temperature ranges from 7°C in winter to 17°C in summer.
HMS/m A1 is accessed by boat from Selsey, West Sussex, United Kingdom. A dive permit is required.
| Month | Temp | Visibility | Access | Marine life |
|---|---|---|---|---|
| Jan | 7.0°C | 3.0m | poor | Minimal — winter conditions |
| Feb | 7.5°C | 3.0m | poor | Minimal — winter conditions |
| Mar | 8.0°C | 4.0m | poor | Minimal — winter conditions |
| Apr | 9.5°C | 5.0m | marginal | Moderate — season starting |
| May | 11.0°C | 6.0m | good | Good — wrasse, pollack, cuttlefish, crabs |
| Jun | 13.0°C | 8.0m | good | Good — wrasse, pollack, cuttlefish, crabs |
| Jul | 15.5°C | 10.0m | good | Peak — bass, bream, cuttlefish, lobster, nudibranchs |
| Aug | 17.0°C | 12.0m | good | Peak — bass, bream, cuttlefish, lobster, nudibranchs |
| Sep | 16.0°C | 10.0m | good | Good — wrasse, pollack, cuttlefish, crabs |
| Oct | 13.5°C | 6.0m | marginal | Good — wrasse, pollack |
| Nov | 10.0°C | 4.0m | poor | Minimal — winter conditions |
| Dec | 8.0°C | 3.0m | poor | Minimal — winter conditions |
3 evidence records from 3 sources.
First British-designed submarine. Sank August 1911 as unmanned target off Selsey Bill. Tidal currents moved wreck ~5 miles to Bracklesham Bay.
Designated historic wreck under Protection of Wrecks Act 1973 since 1998. Virtually intact, partially buried.
NAS dive trail available. Rare opportunity to explore Britain's earliest submarine. ~12m depth.