Two of the eight Type IXA submarines (U-37 and U-38) would become the 6th and 10th most successful U-boats that saw service in World War II, sinking 53 and 35 ships respectively.

All of the Type IXA submarines were sunk fairly early in the war except for U-37 and U-38, which were scuttled in May 1945 to prevent them from falling into the hands of the Allies.

The class had two MAN M 9 V 40/46 supercharged 9-cylinder diesel engines that produced 4,400 PS (4,300 shp; 3,200 kW) as well as two SSW 2 GU 345/34 double-acting electric motors that produced 1,000 PS (986 shp; 735 kW) and allowed them to travel at 18.2 knots (33.7 km/h; 20.9 mph) while surfaced and 7.7 knots (14.3 km/h; 8.9 mph) submerged.

This process could take several hours for just one torpedo, during which the U-boat was unable to dive, making it an easy target for Allied aircraft.

[6][7] The Type IXA submarines were equipped with a 10.5 cm (4.13 in) L/45 deck gun on a Utof mounting forward of the conning tower.

After being commissioned and deployed, the Type IXA submarines were stationed in the German port city of Wilhelmshaven.

Following just over a year of construction, she was launched from the Bremen shipyards on 14 May 1938 and commissioned into the Kriegsmarine on 4 August 1938 under the command of Kapitänleutnant Heinrich Schuch as a member of the 6th U-boat Flotilla.

[12] U-37 was by far the most successful Type IXA U-boat and the sixth most successful U-boat in World War II,[13] sinking 53 merchant ships for a total of 200,063 gross register tons (GRT), along with two warships[14] during eleven war patrols from August 1939 to March 1941.

[15] In spite of these victories, U-37 was later withdrawn from combat service and was used for training submarine crews until the end of the war.

[12] The keel for U-38 was laid down on 15 April 1937 and after over a year and a half of construction she was commissioned on 24 October 1938 with Oberleutnant zur See Heinrich Liebe in command.

[13] With World War II drawing to a disastrous close for Germany, U-38 was scuttled by her own crew west of Wesermünde on 5 May 1945.

She was commissioned over a year later on 10 December 1938 with Kapitänleutnant Gerhard Glattes in command as a member of the 6th U-boat Flotilla.

She was launched from Bremen on 9 November 1938 and commissioned on 11 February 1939 with Kapitänleutnant Werner von Schmidt in command.

She sank on 13 October 1939 after hitting mines in the English Channel while attempting a short cut to a rendezvous with other U-boats.

On 5 February 1940, U-41 was sunk after a depth charge attack by the British destroyer HMS Antelope off the coast of Ireland.

U-43 was sunk on 30 July 1943 southwest of the Azores by a torpedo dropped by a United States Navy aircraft from the escort carrier Santee; all 55 hands were lost.

[24] U-44 was ordered by the Kriegsmarine on 21 November 1936 and was laid down on 15 September 1938 by AG Weser, Bremen as yard number 949.