HMS Poseidon

HMS Poseidon (P99) was a Parthian class submarine designed and built for the United Kingdom Royal Navy, launched in 1929. It spent most of its short career assigned to the Yellow Sea region.

At about 12:45 pm on 9 June 1931, whilst exercising on the surface with the submarine tender HMS Marazion 20 miles north of the vessels' base at Weihai, China and despite excellent visibility Poseidon collided with the Chinese merchant steamer SS Yuta.

Thirty of the submarine's crew managed to scramble into the water before the submarine sank to the seabed 130 feet below within a few minutes. Poseidon was equipped with Davis Submerged Escape Apparatus which had come into service two years earlier. This was a closed circuit underwater breathing system which provided the wearer with a supply of pure oxygen and a canvas drogue to slow the rate of ascent. Despite the submarine not being equipped with specialised escape compartments or flooding valves, eight of the crew managed to leave the forward end of the boat, although two failed to reach the surface and one died later. 22 crew died in total.

A consequence of the successful escape of part of the crew was to change Admiralty policy from advising crews to wait for the arrival of assistance to attempting to escape from the submarine as soon as possible. This policy was announced in the House of Commons in March 1934.

References

• "HMS Poseidon". Battleships-Cruisers.co.uk. Retrieved 2006-12-02.
• "HMS Poseidon". Submariner Association - Barrow in Furness Branch. Retrieved 2006-12-02.
• "H.M. Submarine Poseidon". Britsub. Retrieved 2006-12-02.