HMS D3

HMS D3 was a British D class submarine built by Vickers, Barrow. D3 was laid down on 15 March 1910 and was commissioned on 30 August 1911.

During her career, D3 returned from the second Heligoland Bight patrol along with D2, E5 and E7.

Sinking
D3 met her fate on 12 March 1918. She was mistakenly bombed and sunk by a French airship AT-0 off Fecamp in the English Channel and lost with all hands. AT-0 was patrolling when at 1420 a vessel was spotted to her north east. The airship drew close for recognition purposes and according to her commander, Lieutenant (RCN) William McKinstry Heriot-Maitland-Dougall the submarine fired rockets at her. Four 52-kg bombs were dropped by the airship. The submarine disappeared but several minutes later men were seen in the water. Attempts were made by the airship to rescue the men but it proved too difficult. The airship withdrew to seek help but all the men had drowned by the time it arrived. It is clear that D3 was the victim of a serious identification error on the part of the French airship, with identification rockets being mistaken for aggressive gunfire.