© Shipwreck Preservation Society of Newfoundland & Labrador Inc. 2019
data source: Gordon Smith (1989) The War at Sea: Royal & Dominion Navy Actions in World War 2. Ian Allan Ltd., Shepperton, UK.
A graph of the numbers of Allied & Neutral merchant ships and German U-boats sunk per month in the North Atlantic Ocean from January 1942 until December 1943.
Allied shipping losses rose from 50 ships per month in January 1942 to a peak of 124 per month in June 1942. Allied shipping losses then gradually dropped to just 4 ships per month in June 1943.
In contrast, German U-boat losses were 1 per month in January 1942 and remained below 15 per month until they peaked at 37 per month in May 1943.
May 1943 is considered the turning point of the Battle of the Atlantic. Almost every month afterwards the Allies sank more U-boats than the Germans sank Allied cargo ships. In response to those crippling losses, the German Navy withdrew most of its U-boats from attacking the mid-Atlantic convoys in May 1943.