The HMS Stubborn (P 238) was a 66m S-class submarine scuttled by the Royal Navy on the 30th April 1946 to be used for ASDIC practice, and is up-right on a sandy bottom. Because of the depth, the no-reference descent and the mandatory deco-stop in open water, this dive is limited to very experienced divers.

As you go down, the wreck arises from the deep navy blue, covered in hundreds of brightly coloured sponges and shoals of damselfish are to be seen around the conning tower. An old grouper lives under the bilge and you can occasionally meet him. After 12min spent on the wreck, you ascend from the conning tower back to the boat and prepare to stay at 5m (15ft) for a long deco-stop.

Location:

About 3 nautical miles north-east of St Paul’s Bay.

Access:

By boat.

Conditions:

Completely exposed to all winds and so should be done only in perfect weather.

Average depth:

57m

Maximum depth:

57m

Average visibility:

50m