Date of Loss
K15 was moored alongside the cruiser HMS Canterbury, on 25th June 1921, in the tidal basin at Portsmouth. Most of the crew were on leave when a watch keeper conducting rounds discovered the stern awash and the submarine sinking. The watch were quickly roused and scrambled aboard the Canterbury. The submarine slowly submerged amid streams of bubbles. Following the investigation, the accident was subsequently blamed on hydraulic oil expanding in the hot weather and contracting. As the temperature dropped the loss of hydraulic pressure caused main vents to open.
Fortunately, nobody lost their lives as a result of this accident and K15 was raised the following month and sold in August 1924
