SM UB-28

SM UB-28 was a German Type UB II submarine or U-boat in the German Imperial Navy (Kaiserliche Marine) during World War I. The U-boat was ordered on 30 April 1915 and launched on 20 December 1915. She was commissioned into the German Imperial Navy on 27 December 1915 as SM UB-28.

UB-28 was surrendered to Britain in accordance with the requirements of the Armistice with Germany on 24 November 1918. She was ultimately broken up at Bo'ness in 1919-20.

Design
A Type UB II submarine, UB-28 had a displacement of 265 t when at the surface and 291 t while submerged. She had a total length of 36.13 m, a beam of 4.36 m, and a draught of 3.66 m. The submarine was powered by two Benz six-cylinder diesel engines producing a total 267 PS, two Siemens-Schuckert electric motors producing 280 PS, and one propeller shaft. She was capable of operating at depths of up to 50 m.

The submarine had a maximum surface speed of 8.9 kn and a maximum submerged speed of 5.72 kn. When submerged, she could operate for 45 nmi at 4 kn; when surfaced, she could travel 7200 nmi at 5 kn. UB-28 was fitted with two 50 cm torpedo tubes, four torpedoes, and one 5 cm SK L/40 deck gun. She had a complement of twenty-one crew members and two officers and a thirty-second dive time.