Type: IX-C40
Built by: AG Weser (Bremen)
Launched. 11 March 1942
Commissioned: 10 July 1942
Feldpost Nr.: M05693
Sunk: 12 May 1943
Sunk by HMS HESPERUS (DD)
Location sunk: North of the Azores
Position sunk: 41 degrees 54' N x 31 degrees 49'W (all hands, 53 men lost)

The only Skipper of U-186 was Kapitainleutnant Siegfried Hesemann, who served from the commissioning to the loss. U-186 had only two Feindfahrten (war patrols), both in the North Atlantic. She was lost on the second.

SHIPS SUNK BY U-186 UNDER HESEMANN
01.11.43	OCEAN VAGABOND	Brit stmr	7,174 GRT
02.23.43	HASTINGS	Amer stmr	5,401 GRT

(HASTINGS was an older ship, built in 1920. She was owned by Waterman SS Co. and operated by the WSA. Under Master Richard West, she drew 17 feet under her cargo of 1,500 tons of coal slag (ballast) and was making 91/2 knots when attacked. Her armament consisted of one four-inch deck gun, two .30 cal machine guns and four 20mm automatic AA guns.

She departed Milford Haven in Wales bound for New York in station #12 in Convoy ON.166 when a lookout spotted the torpedo coming in, just as it was about to strike. The torpedo hit portside at the 95 hold and the explosion flooded the engine room, sprung the bulkheads between #4 and #5 holds, destroyed the steering gear and cut the ship's power.

Captain West ordered the engines secured immediately, and gave the abandon ship order. The ten officers, thirty-one men, twenty Armed Guards and one passenger immediately left the ship in three boats and two rafts. Due to the nature of her cargo, HASTINGS sank in only seven minutes, going down by the stern.

The Canadian HMCS CHILLIWACK (K-131) picked up the entire gun crew, nine of the officers, twenty-three of the men and the passenger, landing them at St. Johns shortly after the attack. One officer and eight men were lost in this action.

02.23.43	unknown	unknown	unknown
02.23.43	EULIMA	Brit tnkr	6,207 GRT
(U-186 attacked Convoy ON.166 and saw a hit on HASTINGS. The second detonation was probably the same ship, as there was no confirmation of a second ship being hit. The next spread of torpedoes, five minutes later, only hit EULIMA and disabled her. U-186 returned some four hours later and sank her with one more torpedo.)
SHIPS DAMAGED BY U-186 UNDER HESEMANN
02.23.43	EULIMA	Brit tnkr	6,207 GRT
02.23.43	unknown	unknown	unknown