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A photo of the U-175

Date of Action: 17 April 1943

USCG Units Involved: USCGC Spencer

Sinking/Capture/Assist? Sinking

Location: 51.25N x 27.28W

Credit by U.S. Navy? Yes 

Enemy Warship's Commanding Officer: Kapitänleutnant Heinrich Bruns

Enemy Casualties: 13 killed in action; 41 survivors

USCG Casualties: 1 killed (friendly fire)


On 17 April 1943 USCGC Spencer located U-175 on sonar as the U-boat attempted a submerged daylight attack from within Convoy HX-233 as the convoy made its way across the mid-Atlantic. The U-boat's commanding officer had the tanker S.S. G. Harrison Smith in his periscope sights but Spencer intervened before the U-boat could fire a spread of torpedoes at the target. Sailing between the columns of ships, the cutter delivered three accurate depth charge attacks on the unsuspecting U-boat.  As one of the U-175's crew later recounted, "The (depth charges) were bad ... everything was shaking ... we came up and saw you in the periscope, but you saw us and we knew it was all over ... our chance to get you was gone."

Damaged heavily, the submarine surfaced and Spencer, Duane, and many of the merchant ships' naval armed guard opened fire. U-175's crew abandoned their submarine after opening its dive valves. Spencer sent over a boarding party. LT Ross P. Bullard climbed aboard and determined that the U-boat was sinking too fast to salvage. Nevertheless, Bullard became the first American serviceman to board an enemy warship underway at sea since the 19th century.

Afterward, the cutters rescued the surviving 41 German crewmen. One of Spencer's crew had been killed by friendly fire and several others were wounded.  Admiral Sir Max Horton, Royal Navy, Commander in Chief of the Western Approaches, signaled the crew of the Spencer "well done."


W. A. Haskell.  Shadows on the Horizon: The Battle of Convoy HX-233.  London: Chatham Publishing, 1998.

________. Schatten am Horizont: Die Schlacht um den Geleitzug HX-233.  Berlin: Verlag E. S. Mittler & Sohn GmbH, 2003.

Last Modified 12/21/2016