US Coast Guard crew of cutter Spencer watched as a depth charge exploded near U-175, North Atlantic, 500 nautical miles WSW of Ireland, 17 Apr 1943. Photo by Jack January

The US Naval Institute’s April 2024 edition of Naval History magazine has an excellent article about USCGC Spencer’s destruction of U-175 on 17 April 1943, A Nautical Knife Fight, written by CPO William A. Bleyer, USCG. I have added the link to my heritage page.

I have read several accounts of this action, and this is the best and most detailed.

USCGC Spencer (WPG-36) in 1942 or 1943. Spencer sank U-175 with assistance of USCGC Duane, on April 17, 1943.

Spencer was the Coast Guard’s most successful ASW ship, sinking at least two U-boats (U-633 on March 1943 and U-175 17 April 1943) and possibly a third.

USCG Cmdr Harold S. Berdine of cutter Spencer talking with US Navy Capt Paul Heineman of the Escort Group A-3 after sinking German submarine U-175, North Atlantic, 500 nautical miles WSW of Ireland, 17 Apr 1943. US Coast Guard photo by Jack January

Spencer was one of seven 327 foot Secretary class cutters. As a class they were extremely successful. Unfortunately, one was lost 29 January 1942, after being torpedoed. Another of the class, USCGC Campbell, famously rammed and sank U-606 on 22 February 1943, after the U-boat was forced to the surface by the Polish destroyer Burza. I had the privilege of being XO on one of the class, USCGC Duane, which assisted Spencer in the sinking of U-175 and rescuing survivors.

Related:

• “How Spencer Became the Coast Guard’s Top U-Boat Killer, Thank You Royal Navy”
• More on the Coast Guard’s role in the Battle of the Atlantic here.
• A book review and thoughts on modern convoys here.