SM U-87

SM U-87 was one of the 329 submarines serving in the Imperial German Navy (Kaiserliche Marine) in World War I. U-87 was engaged in the naval warfare and took part in the First Battle of the Atlantic. She sank some 22 merchant vessels before 25 December 1917, when HMS Buttercup (1916) rammed U-87 in the Irish Sea and depth-charged her. Then the P-class sloop P.56 sank her. U-87's entire crew of 44 were lost.

Design
Type U 87 submarines were preceded by the shorter Type U 81 submarines. The first of its type, U-87 had a displacement of 757 t when at the surface and 998 t while submerged. She had a total length of 65.80 m, a pressure hull length of 50.07 m, a beam of 6.20 m, a height of 9.35 m, and a draught of 3.88 m. The submarine was powered by two 2400 PS engines for use while surfaced, and two 1200 PS engines for use while submerged. She had two propeller shafts. She was capable of operating at depths of up to 50 m.

The submarine had a maximum surface speed of 15.6 kn and a maximum submerged speed of 8.6 kn. When submerged, she could operate for 56 nmi at 5 kn; when surfaced, she could travel 11380 nmi at 8 kn. U-87 was fitted with four 50 cm torpedo tubes (two at the bow and two at the stern), ten to twelve torpedoes, one 10.5 cm SK L/45 deck gun, and one 8.8 cm SK L/30 deck gun. She had a complement of thirty-six (thirty-two crew members and four officers).

Fate and discovery
In August 2017, researchers from Bangor University in Wales announced they had discovered the sunken wreck of U-87 while conducting multibeam surveys 10 miles northwest of Bardsey Island as part of the marine renewable energy SEACAMS 2 project. Detailed sonar images reveal the wreck to be lying in one piece with what appears to be a large area of damage near the conning tower, presumably caused by in the ramming collision by escort P.56.