German submarine U-537

German submarine U-537 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine during World War II. Her keel was laid down on 10 April 1942 by Deutsche Werft in Hamburg. She was commissioned on 27 January 1943 with Kapitänleutnant Peter Schrewe in command. Schrewe commanded the boat for nearly two years, until her loss.

U-537 conducted three patrols and holds the distinction of making the only armed German landing in North America during World War II, when her crew installed the automatic Weather Station Kurt in Martin Bay, Labrador on 22 October 1943. She was then sent to the Far East. On 10 November 1944 in the Java Sea east of Surabaya, U-537 was sunk with all hands—58 officers and men—by torpedoes from USS Flounder (SS-251).

Design
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-537 had a displacement of 1144 t when at the surface and 1257 t while submerged. The U-boat had a total length of 76.76 m, a pressure hull length of 58.75 m, a beam of 6.86 m, a height of 9.60 m, and a draught of 4.67 m. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4400 PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000 shp for use while submerged. She had two shafts and two 1.92 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 18.3 kn and a maximum submerged speed of 7.3 kn. When submerged, the boat could operate for 63 nmi at 4 kn; when surfaced, she could travel 13850 nmi at 10 kn. U-537 was fitted with six 53.3 cm torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm SK C/32 naval gun, 180 rounds, and a 3.7 cm SK C/30 as well as a 2 cm C/30 anti-aircraft gun. The boat had a complement of forty-eight.

First patrol
U-537 left Kiel on 18 September 1943 and sailed to Bergen, Norway, departing from there on her first patrol on 30 September. She sailed across the North Atlantic, and on 22 October she set up Wetter-Funkgerät Land-26 (code-named "Kurt") automatic weather station in Martin Bay, Labrador. The weather station was only discovered by accident by Canadian authorities in 1981.

While on anti-shipping patrol off Newfoundland on 31 October, the U-boat was attacked by a Canadian Hudson aircraft from No. 11 Squadron RCAF, which fired eight rockets, all missing. On 10 November a Canadian Catalina aircraft from No. 5 Squadron RCAF attacked her with four depth charges off Cape Race. The U-boat escaped unharmed, but the next day another Catalina of 5 Squadron attacked with four depth charges which slightly damaged the submarine. Surface ships then joined the hunt, but all failed to locate her, and U-537 arrived safely at Lorient on 8 December.

Second patrol
U-537 sailed from Lorient on 25 March 1944 and traveled around Africa, and then crossed the Indian Ocean to Batavia, which she reached on 2 August after a voyage of 131 days.

Third patrol
U-537 left Batavia for Surabaya in Indonesia on 1 October 1944, and began her third and final patrol on 9 November. On 10 November, she was spotted and sunk with all hands — 58 officers and men — in the Java Sea, at position -7.21667°N, 115.28333°W, by torpedoes from USS Flounder (SS-251). U-537 was one of 10 German U-boats lost in Asian or East African waters during the war.