SM U-18

SM U-18 was one of 329 submarines serving in the Imperial German Navy in World War I. U-18 engaged in the commerce warfare in the First Battle of the Atlantic.

Launched in October 1914, she was commanded by Kaptlt. von Hennig.

On her third mission, on 23 November U-18 penetrated the fleet anchorage of Scapa Flow via Hoxa Sound, following a steamer through the boom and entering the anchorage with little difficulty. However, the fleet was absent, being dispersed in achorages on the west coast of Scotland and Ireland. As U-18 was making her way back out through Hoxa Sound to the open sea, her periscope was spotted by a guard boat. The trawler Dorothy Gray altered course and rammed the periscope, rendering it unserviceable. U-18 then suffered a failure of her diving plane motor and the boat became unable to maintain her depth, at one point even impacting the seabed. She was rammed a second time by the Dorothy Gray and eventually, her captain was forced to surface and scuttle his command just outside the Hoxa Gate, and all crewmembers except one were picked up by British boats. 58.41N, 02.55W. One man died and 22 were captured.

The wreck lies 75 m below the surface just outside the Hoxa Gate, at 58.68333°N, -2.91667°W.