This is the sister ship to the P29 at Cirkewwa (ex-Boltenhagen). The main differences are firstly the depth of the P31, which is 18m with a maximum of 21m under the bow, and secondly it is possible to enter the P31 at the stern and swim all the way to the bow without having to exit and re-enter the wreck. Other differences include the mast having been removed, and also the stern is buried in the sand after the wreck moved a substantial distance during storms over the winter 2010-2011. The wreck now lies about 25m from the navigational hazard buoy in the direction of Alex's cave. There is also quite a large amount of sand inside the engine room, but this does not prevent swimming through the wreck.

At 53m long the P31 is an excellent site for divers of all levels, even newly qualified Open Water divers. There is no reef nearby which means that the dive has a square profile, with a safety stop at 5m. It is therefore possible to explore the whole wreck, inside and out, in about 35 minutes. On the sand around the wreck you may see rays, flounders and razor fish. On the wreck have been found trigger fish, filefish, octopus, nudbranchs and numerous small reef fish. Mussels, oysters and tube worms have started to colonise the wreck and the buoy after only two years in the water.