German submarine U-28 was a Type VIIA U-boat of Nazi Germany's Kriegsmarine during World War II. Her keel was laid down on 2 December 1935, by DeSchiMAG AG Weser of Bremen. She was launched on 14 July 1936, and commissioned into Kriegsmarine on 12 September 1936, with Kapitänleutnant Wilhelm Ambrosius in command. Ambrosius was succeeded by nine other commanding officers over the next eight years. U-28 conducted seven war patrols between 19 August 1939 and 15 November 1940, all under the command of Kapitänleutnant Günter Kuhnke, sinking 13 ships totaling and damaging two others totaling . After her third patrol, U-28 became a training vessel and was used to bring new U-boat crews up to standard. She was later sunk in an accident on 17 March 1944 and stricken on 4 August 1944. Construction and design Construction U-28 was ordered by the Kriegsmarine on 1 April 1935 as part of the German Plan Z and in violation of the Treaty of Versailles. Her keel was laid down in the AG Weser shipyard in Bremen as yard number 909 on 2 December 1935. After about ten months of construction, she was launched on 14 July 1936 and commissioned into the Kriegsmarine as the third Type VIIA submarine on 12 September 1936 under the command of Kapitänleutnant Wilhelm Ambrosius. Design Like all Type VIIA submarines, U-28 displaced while surfaced and when submerged. She was in overall length and had a pressure hull. U-28s propulsion consisted of two MAN 6-cylinder 4-stroke M 6 V 40/46 diesel engines that totaled . Her maximum rpm was between 470 and 485. The submarine was also equipped with two Brown, Boveri & Cie GG UB 720/8 electric motors that totaled . Their maximum rpm was 322. These power plants gave U-28 a maximum speed of while surfaced and when submerged. She had a range of while traveling at on the surface and at when submerged. The U-boat's test depth was but she could go as deep as without having her hull crushed. U-28s armament consisted of five torpedo tubes, (four located in the bow and one in the stern). She could have up to eleven torpedoes on board or 22 TMA mines or 33 TMB mines. U-28 was also equipped with a C35 88 mm gun/L45 deck gun with 220 rounds. Her anti-aircraft defenses consisted of one anti-aircraft gun. Service history First patrol U-28s first war patrol