The minefields laid by U78 in mid 1916 caused the loss of 2 ships in Welsh Waters - the KELVINA (NPRN 273179) on 2 September off Caldey Island and the Navy trawler LOCH SHIEL (NPRN 273056) 7 miles west of the Helwick light. U-78 was one of 10 commissioned UE1 type submarines and was built by Vulcan, Hamburg. Technical specifications are given as 755 tons displacement at surface, 832 tons displacement submerged; 58m length x 5.9m breadth x 4.6m draught (8.2m height). Armed with 4 torpedos, 38 mines, and 130 rounds of 105mm rounds for its deck gun. Its commander from 20 April 1916 to 15 Janaury1918 was Kap Lt Otto Droscher. It was torpedoed in the North Sea on 27 October 1918 and lost with all hands.

Sources include:
Armstrong, P and Young, R, 2010, Silent Warriors: Submarine Wrecks of the United Kingdom, Volume 3, pg15

WWW resources:
http://www.uboat.net/wwi/boats/index.html?boat=78

Maritime Officer, RCAHMW, June 1917.