sourced story
March-May 1943Reputable sourceWell documented

Germany loses forty-three U-boats in a single month, and Dönitz pulls the rest home

On the timeline · around March-May 1943 · The Tide TurnsThe Tide TurnsGermany loses forty-three U-boats in a single month, and Dönitz pulls the rest home1943

What happened

As late as March 1943, German U-boats were sinking Allied merchant shipping in the North Atlantic faster than the Allies could replace it. Within weeks, new escort tactics, long-range aircraft coverage, improved radar, and better convoy organization turned the campaign around. In May 1943, the German navy lost 43 U-boats to all causes, equal to about 25 percent of its entire operational force in a single month. On 24 May 1943, Grand Admiral Karl Dönitz, whose own son had been killed aboard one of the lost submarines, ordered a general recall, pulling most U-boats out of the North Atlantic convoy routes rather than keep feeding them into a battle Germany was now losing.

Why it matters

Withdrawing the U-boats did not just end one bad month, it effectively ended Germany's ability to threaten the Atlantic supply line for the rest of the war. Convoys carrying troops and equipment for the eventual invasion of France could now cross with dramatically lower losses, part of why the Allies could build up the men and material in Britain that made D-Day possible a year later.

How we know

The Naval History and Heritage Command's official H-Gram series, written by the command's Director of Naval History, states the May 1943 losses at 43 U-boats lost to all causes, equal to 25 percent of the operational force, and gives 24 May 1943 as the date of Dönitz's recall order, including the loss of his own son aboard U-954.

Sources

See something wrong? . Corrections with a source get fixed fastest.

Part of a timelineWorld War II59 events · From a staged skirmish at a bridge outside Beijing to a charter signed in San Francisco, the deadliest conflict in history, every event sourced.View all →