HMS K5 was one of the K-class submarines that served in the Royal Navy between 1917 and 1921. She was lost with all hands when she sank en route to a mock battle in the Bay of Biscay.

War service

At the end of the war in 1918 K5 was part of the 12th Submarine Flotilla based at Rosyth, along with 6 others of the K class.

Loss

The K5 left Torbay on 19 January 1921 with the , , and for a mock battle in the Bay of Biscay.

The submarine was commanded by an experienced officer, Lieutenant-Commander John A Gaimes, DSO, RN, but had a new crew. The other officers on board were Lieutenant F Cuddeford, Engineer-Lieutenant E Bowler, Acting Engineer-Lieutenant G Baker, Lieutenant B Clark and Acting Lieutenant R Middlement. The full complement included 51 other ranks on board.

All 57 hands were lost on 20 January about 120 miles south-west of the Isles of Scilly. She had signalled that she was diving but she did not surface at the end of the exercise. After a battery cover and a sailor's "ditty box" were recovered it was presumed that she had somehow gone past her maximum depth.

On return from her exercises in the Mediterranean in 1922 the and the rest of the fleet dropped wreaths and held a memorial service where the K5 had gone down.

Problems with the K-class

Retired Rear-Admiral S.S. Hall wrote in The Times (24 January 1921, p. 10): "...it may be taken as certain that the loss of the vessel was due to some delay to checking the downward momentum gained by the vessel being overtrimmed in diving, either by admitting compressed air too slowly to too many tanks at one time, to tanks only partially full, or to a sea connexion being closed prematurely."

The waters where the battle exercises were taking place were so deep that the vessel would have been crushed, losing control due to the intake of water. Admiral Hall wrote that it was "not clear why the 'K' class should be taken for cruises in the Atlantic in winter." He describes the submarines as 'freaks' that were designed especially for the conditions of the North Sea during World War I. "The high surface speed necessitates great length, and the further complication of steam demands very large openings for funnels and air intakes to boiler rooms. These have always been a source of great anxiety in bad weather or in rapid diving."

suffered a similar fate during her acceptance trials, when she foundered with the loss of 32 of those on board. The cause of the incident was related to the openings Hall refers to.

References

• "K5 sunk with all hands lost." (24 January, 1921), The Times, p. 10, 11 & 12.