SM UC-57

SM UC-57 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. The U-boat was ordered on 12 January 1916, laid down on 14 March 1916, and was launched on 7 September 1916. She was commissioned into the German Imperial Navy on 22 January 1917 as SM UC-57. In seven patrols UC-57 was credited with sinking 5 ships, either by torpedo or by mines laid.

UC-57 disappeared in 1917 after landing a party of Finnish Jägers and 4 tons of munitions on the island of Hamnskär, circa 30 km from Loviisa, on 18 November. UC-57 was going to remain on the seabed overnight and then return to Germany but never arrived. She was probably sunk by a Russian mine.

Design
A Type UC II submarine, UC-57 had a displacement of 415 t when at the surface and 498 t while submerged. She had a length overall of 50.52 m, a beam of 5.22 m, and a draught of 3.61 m. The submarine was powered by two six-cylinder four-stroke diesel engines each producing 290 - 300 PS (a total of 580 - 600 PS), two electric motors producing 620 PS, and two propeller shafts. She had a dive time of 48 seconds and was capable of operating at a depth of 50 m.

The submarine had a maximum surface speed of 11.6 kn and a submerged speed of 7.3 kn. When submerged, she could operate for 52 nmi at 4 kn; when surfaced, she could travel 8660 to 9450 nmi at 7 kn. UC-57 was fitted with six 100 cm mine tubes, eighteen UC 200 mines, three 50 cm torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 8.8 cm Uk L/30 deck gun. Her complement was twenty-six crew members.