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Type I submarine

From Wikipedia, the free encyclopedia
U-25, a Type I U-boat.
Class overview
BuildersDeschimag, Bremen
Operators Kriegsmarine
Preceded bySpanish Type E1
Succeeded by
Cost4,500,000 ℛ︁ℳ︁
In commission1936 – 1940
General characteristics
Length72.39 m (237 ft 6 in)
Beam6.21 m (20 ft 4 in)
Draft4.30 m (14 ft 1 in)
  • 17.7–18.6 knots (32.8–34.4 km/h; 20.4–21.4 mph) surfaced
  • 8.3 knots (15.4 km/h; 9.6 mph) submerged
  • 7,900 nmi (14,600 km; 9,100 mi) at 10 knots (19 km/h; 12 mph) surfaced
  • 78 nmi (144 km; 90 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth200 m (660 ft)
Complement4 officers, 39 enlisted

The Type I U-boat was the first post–World War I attempt to produce an oceangoing submarine for Nazi Germany's Kriegsmarine. The type was based on the Spanish Type E-1[1] and Finnish CV707, which were both designed by Ingenieurskantoor voor Scheepsbouw.[2] Only two Type IAs were built.[3] They were not a successful design : due to its single rudder they had a large turning circle and were not very manoeuvrable. The gravity center of the U-boat was too forward so on surface the type I had its propellers exposed when she was pitching. Whilst submerged there were problems with depth keeping and stability as air bubbles in fuel tanks wobbled back and forth. Diving was very slow: at full speed and with six tons of negative buoyancy it took forty seconds to reach ten metres depth. As a result, the type was discontinued and a new type IX class oceangoing U-boats was designed.[4]

Service history[edit]

Constructed by Deschimag in Bremen, the first Type IA was launched on 14 February 1936.[5] The two boats produced, U-25 and U-26, were primarily used as training vessels and for propaganda purposes to fly the Nazi flag. In 1940, the boats were called into combat duty due to the shortage of available submarines.[6] Both boats experienced short, but successful combat careers. U-25 participated in five war cruises, sinking eight enemy ships. On 3 August 1940, while on a mine laying mission near Norway, U-25 struck a mine and sank with all hands on board.[1]

U-26 carried out eight war cruises, sinking three merchant ships on its first mission laying mines. On its second war cruise it became the first U-boat during World War II to enter the Mediterranean Sea. U-26 participated in three other successful war patrols, sinking four additional merchant ships. On its eighth war cruise the boat sank three merchant ships and damaged another ship the next day. The attack on this ship led to severe depth-charging by two British warships, including HMS Gladiolus.[1] Unable to dive, U-26 was forced to surface where she was bombed by a Sunderland flying boat. The crew scuttled the submarine and were rescued by Allied warships.

List of Type I submarines[edit]


  1. ^ a b c Gröner 1991, p. 39.
  2. ^ Rössler (2001), pp. 98-99.
  3. ^ Showell (2006), p. 73.
  4. ^ Paterson 2003, p. x-xi.
  5. ^ Sharpe (1998), p. 13.
  6. ^ Williamson (2005), p. 16.


  • Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
  • Paterson, Lawrence (2003). Second U-Boat Flottila. Leo Cooper. ISBN 0-85052-917-4.
  • Sharpe, Peter (1998). U-Boat Fact File: Detailed Service Histories of the Submarines Operated by the Kriegsmarine 1935-1945. Leicester: Midland Publishing. ISBN 1-85780-072-9.
  • Showell, Jak P. Mallmann (2006). The U-boat Century: German Submarine Warfare 1906-2006. London: Chatham Publishing. ISBN 9781861762412.
  • Rössler, Eberhard (2001). The U-boat: The evolution and technical history of German submarines. London: Cassell & Co. ISBN 0-304-36120-8.
  • Williamson, Gordon (2005). Wolf Pack: The Story of the U-boat in World War II. Oxford: Osprey Publishing. ISBN 1-84176-872-3.

External links[edit]