HMS D3 (Lt W McK Maitland-Dougall, RCN) survived an accidental depth charge attack by the destroyer HMS ACHATES on 7 February 1918.
However, she was lost with All Hands on 15 March 1918 when she was mistakenly attacked by a French airship with 52 kilo bombs. The airship, commanded by Lt Saint Remy, sighted D3 on the surface, who fired rockets towards it (presumably to identify herself), but the airship thought it was under attack. A total of 6 bombs were dropped and the submarine attempted to dive. She was damaged by the bombs and attempted subsequently to resurface but only the fin emerged before she sank.
Four submariners escaped and the airship tried to shout down to them. One of the submariners shouted, “You got us.” Saint Remy, realising that it was a British boat, tried to get vessels in the area to pick up the submariners. Unfortunately, no survivors were found.
Lt Maitland-Dougall was the first Canadian officer to command a British submarine.