SM U-85 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-85 was engaged in the naval warfare and took part in the First Battle of the Atlantic.
Initially, to had one 10.5 cm gun with 140-240 rounds. - on the other hand had two 8.8 cm guns. In 1917, - were refitted with a single 10.5 cm gun (240 rounds)
Type U 81 submarines were preceded by the shorter Type UE I submarines. U-85 had a displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two engines for use while surfaced, and two engines for use while submerged. She had two propeller shafts. She was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, she could operate for at ; when surfaced, she could travel at . U-85 was fitted with four torpedo tubes (two at the bow and two at the stern), twelve to sixteen torpedoes, and one SK L/45 deck gun (from 1917). She had a complement of thirty-five (thirty-one crew members and four officers).