German submarine U-186

German submarine U-186 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine built for service during World War II. Her keel was laid down on 24 July 1941 by DeSchiMAG AG Weser in Bremen as yard number 1026. She was launched on 11 March 1942 and commissioned on 10 July with Korvettenkapitän Siegfried Hesemann in command.

The U-boat's service began with training as part of the 4th U-boat Flotilla. She then moved to the 10th flotilla on 1 January 1943 for operations. The submarine carried out two patrols and was a member of nine wolfpacks. She sank three ships totalling.

She was sunk by a British destroyer on 12 May 1943.

Design
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-186 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-186 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-186's first patrol took her from Kiel, across the North Sea and into the Atlantic Ocean through the gap between Iceland and the Faroe Islands. She sank Ocean Vagabond on 11 January 1943 south of Iceland. This ship had already been damaged by GS U-513 in September 1942. U-186 also sank Hastings and Eulima on 23 February 1943 (part of Convoy ON 166) about 310 nmi south of Cape Race (Newfoundland). She arrived at Lorient in occupied France, on 5 March 1943.

Second patrol and loss
The boat departed Lorient on 17 April 1943. On 12 May she was sunk northwest of the Azores by depth charges dropped by the British destroyer HMS Hesperus (H57). Fifty three men died. There were no survivors.

Wolfpacks
U-186 took part in nine wolfpacks, namely:
 * Habicht (10 – 19 January 1943)
 * Haudegen (19 January - 2 February 1943)
 * Nordsturm (2 – 9 February 1943)
 * Haudegen (9 – 15 February 1943)
 * Taifun (15 – 20 February 1943)
 * Amsel (22 April - 3 May 1943)
 * Amsel 4 (3 – 6 May 1943)
 * Rhein (7 – 10 May 1943)
 * Elbe 2 (10 – 12 May 1943)