SM U-166

SM U-166 was one of the 329 submarines serving in the Imperial German Navy. She was a Type Mittel U submarine, launched in 1918. She would have been engaged in naval warfare and taken part in the First Battle of the Atlantic, but it was not commissioned until the end of the war. She surrendered on 21 March 1919 and became the French submarine Jean Roulier until 24 July 1935. U-166 was broken up.

Design
Type U 93 submarines were preceded by the shorter Type U 87 submarines. U-166 had a displacement of 821 t when at the surface and 1002 t while submerged. She had a total length of 71.55 m, a pressure hull length of 56.05 m, a beam of 6.30 m, a height of 8.25 m, and a draught of 3.88 m. The submarine was powered by two 2400 PS engines for use while surfaced, and two 1230 PS engines for use while submerged. She had two propeller shafts and two 1.70 m propellers. She was capable of operating at depths of up to 50 m.

The submarine had a maximum surface speed of 16.2 kn and a maximum submerged speed of 8.2 kn. When submerged, she could operate for 50 nmi at 5 kn; when surfaced, she could travel 8500 nmi at 8 kn. U-166 was fitted with six 50 cm torpedo tubes (four at the bow and two at the stern), twelve to sixteen torpedoes, and one 10.5 cm SK L/45 deck gun. She had a complement of thirty-six (thirty-two crew members and four officers).