SM UB-28 was a German Type UB II submarine or U-boat in the German Imperial Navy (German: 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.
SM UB-45, a u-boat similar to UB-28
|Ordered:||30 April 1915|
|Builder:||AG Weser, Bremen|
|Cost:||1,291,000 German Papiermark|
|Launched:||20 December 1915|
|Commissioned:||27 December 1915|
|Fate:||surrendered 24 November 1918|
|General characteristics y|
|Class and type:||German Type UB II submarine|
|Draught:||3.66 m (12 ft)|
|Test depth:||50 m (160 ft)|
|Complement:||2 officers, 21 men|
|Notes:||30-second diving time|
A German Type UB II submarine, UB-28 had a displacement of 265 tonnes (261 long tons) when at the surface and 291 tonnes (286 long tons) while submerged. She had a total length of 36.13 m (118 ft 6 in), a beam of 4.36 m (14 ft 4 in), and a draught of 3.66 m (12 ft). The submarine was powered by two Benz six-cylinder diesel engines producing a total 267 metric horsepower (263 shp; 196 kW), two Siemens-Schuckert electric motors producing 280 metric horsepower (210 kW; 280 shp), and one propeller shaft. She was capable of operating at depths of up to 50 metres (160 ft).
The submarine had a maximum surface speed of 8.9 knots (16.5 km/h; 10.2 mph) and a maximum submerged speed of 5.72 knots (10.59 km/h; 6.58 mph). When submerged, she could operate for 45 nautical miles (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 7,200 nautical miles (13,300 km; 8,300 mi) at 5 knots (9.3 km/h; 5.8 mph). UB-28 was fitted with two 50 centimetres (20 in) torpedo tubes, four torpedoes, and one 5 cm (2.0 in) SK L/40 deck gun. She had a complement of twenty-one crew members and two officers and a thirty-second dive time.
- "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.
- Bendert, Harald (2000). Die UB-Boote der Kaiserlichen Marine, 1914-1918. Einsätze, Erfolge, Schicksal (in German). Hamburg: Verlag E.S. Mittler & Sohn GmbH. ISBN 3-8132-0713-7.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- Rössler, Eberhard (1979). U-Bootbau bis Ende des 1. Weltkrieges, Konstruktionen für das Ausland und die Jahre 1935 – 1945. Die deutschen U-Boote und ihre Werften (in German). I. Munich: Bernard & Graefe. ISBN 3-7637-5213-7.