SM UB-56 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 19 July 1917 as SM UB-56.

She operated as part of the Flanders Flotilla based in Zeebrugge. UB-56 was sunk at 23:41 on 19 December 1917 at 50°58′N 01°21′E / 50.967°N 1.350°E / 50.967; 1.350 after striking a mine, 37 crew members lost their lives in the event.

Construction

She was built by AG Weser, Bremen and following just under a year of construction, launched at Bremen on 6 June 1917. UB-56 was commissioned later that same year . Like all Type UB III submarines, UB-56 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-56 would carry a crew of up to 3 officer and 31 men and had a cruising range of 9,020 nautical miles (16,710 km; 10,380 mi). UB-56 had a displacement of 516 t (508 long tons) while surfaced and 646 t (636 long tons; 712 short tons) when submerged. Her engines enabled her to travel at 13.4 knots (24.8 km/h; 15.4 mph) when surfaced and 7.8 knots (14.4 km/h; 9.0 mph) when submerged.

Summary of raiding history

Date	Name	Nationality	Tonnage	Fate
13 November 1917	Atlas	United Kingdom	989	Sunk
13 November 1917	Axwell	United Kingdom	1,442	Sunk
17 November 1917	Lalen Mendi	Spain	2,183	Sunk
21 November 1917	Maine	France	773	Sunk