SM UB-12

History
German Empire
Name:	UB-12
Ordered:	15 October 1914
Builder:	AG Weser, Bremen
Yard number:	221
Laid down:	7 November 1914
Launched:	2 March 1915
Commissioned:	29 March 1915
Fate:	disappeared after 19 August 1918
General characteristics
Class and type:	German Type UB I submarine
Displacement:	127 t (125 long tons) surfaced 141 t (139 long tons) submerged
Length:	27.88 m (91.5 ft) (o/a)
Beam:	3.15 m (10 ft 4 in)
Draft:	3.03 m (9 ft 11 in)
Propulsion:	1 × propeller shaft 1 × Körting 4-cylinder diesel engine, 59 bhp (44 kW) 1 × Siemens-Schuckert electric motor, 119 shp (89 kW)
Speed:	7.45 knots (13.80 km/h; 8.57 mph) surfaced 6.24 knots (11.56 km/h; 7.18 mph) submerged
Range:	1,500 nmi (2,800 km; 1,700 mi) at 5 knots (9.3 km/h; 5.8 mph) surfaced 45 nmi (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth:	50 metres (160 ft)
Complement:	14
Armament:	2 × 45 cm (17.7 in) bow torpedo tubes 2 × torpedoes 1 × 8 mm (0.31 in) machine gun
Notes:	33-second diving time
Service record
Part of:	Imperial German Navy: Flandern Flotilla 18 April 1915 – 19 August 1918
Commanders:	Oblt.z.S. Hans Nieland 29 March – 20 November 1915 Oblt.z.S. Wilhelm Kiel 21 November 1915 – 25 June 1916 Oblt.z.S. Georg Gerth 26 June – 4 November 1916 Oblt.z.S. Friedrich Moecke 5 November 1916 – 19 January 1917 Oblt.z.S. Ernst Steindorff 20 January – August 1917 Oblt.z.S. Günther Wigankow 8 August – 23 September 1917 Oblt.z.S. Wilhelm Braun 24 September 1917 – 9 March 1918 Oblt.z.S. Freiherr Nikolaus von Lyncker 10 March – 9 May 1918 Oblt.z.S. Ernst Schöller 10 May – 19 August 1918
Operations:	98 patrols
Victories:	22 merchant ships sunk (10,247 GRT) 1 merchant ship captured as a prize (654 GRT) 1 warship sunk (995 tons)

SM UB-12 was a German Type UB I submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The submarine disappeared in August 1918.

UB-12 was ordered in October 1914 and was laid down at the AG Weser shipyard in Bremen in November. UB-12 was a little under 28 metres (92 ft) in length and displaced between 127 and 141 tonnes (125 and 139 long tons), depending on whether surfaced or submerged. She carried two torpedoes for her two bow torpedo tubes and was also armed with a deck-mounted machine gun. UB-12 was broken into sections and shipped by rail to Antwerp for reassembly. She was launched and commissioned as SM UB-12 in March 1915.

UB-12 spent her entire career in the Flanders Flotilla and sank 22 merchant ships, about half of them British fishing vessels. The U-boat was also responsible for sinking the British destroyer HMS Laforey in 1917. By early 1917, UB-12 had been converted into a minelayer with the replacement of her torpedo tubes with four mine chutes. UB-12 disappeared after 19 August 1918.

After the German Army's rapid advance along the North Sea coast in the earliest stages of World War I, the German Imperial Navy found itself without suitable submarines that could be operated in the narrow and shallow seas off Flanders. Project 34, a design effort begun in mid-August 1914, produced the Type UB I design: a small submarine that could be shipped by rail to a port of operations and quickly assembled. Constrained by railroad size limitations, the UB I design called for a boat about 28 metres (92 ft) long and displacing about 125 t (123 long tons) with two torpedo tubes.

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