HMS E16 (Lt Cdr Duff-Dunbar) (furthest in the image) was the first submarine to encounter and successfully negotiate anti-submarine nets in the Heligoland Bight on 25 July 1915. The following day she torpedoed and sank the German Destroyer V188. On 15 September 1915, whilst patrolling off the Norwegian coast, she sighted a cloud of exhaust from German U-boat U6. E16 successfully attacked and sank U6 picking up five survivors including the CO of the U-boat.
E16 was lost with all hands after striking a mine in the North Sea on 22 August 1916.