sub hunting bay of biscay d-day...

On the eve of the Normandy invasion, the German Kriegsmarine (navy) had 35 operational U-boats located in the Biscay ports of which nine were equipped with snorkels. With the onset of the invasion, the Germans dispatched these nine snorkel boats into the Channel while seven non-snorkel U-boats accompanied them as far as the area between the Isles of Scilly and the Start Point in Devon. As additional U-boats became available, they too were dispatched to join the effort including 19 U-boats from Germany and Norway that were diverted into the contested area. Unfortunately for the Germans, these U-boats ran into a gauntlet of Allied defenses. This included 29 squadrons from RAF Coastal Command’s No. 19 Group that saturated the western approaches and Bay of Biscay thus subjecting the transiting U-boats to the most intense aerial interdiction effort yet encountered. They also faced substantial naval forces including ten support groups that patrolled the western entrance to the English Channel and the area beyond Land’s End. The result was a slaughter of immense proportions. Of the Biscay-based U-boats, eight were sunk while most of the rest were forced to turn back due to battle damage or exhaustion. Of the 19 U-boats circumventing Britain from the north, the situation was even worse as ten were sunk before month’s end while three more aborted their southward trek. When added to four U-boats that were sunk off Norway, this brought to a total of 22 U-boats that were sunk in Western European waters during June 1944. Against this loss, only a handful of U-boats were able to penetrate the Allied defences and engage elements of the invasion fleet. Of these, even fewer scored successes sinking a paltry three American liberty ships worth 21,550 tons, a LST and the British frigates Mourne and Blackwood. Given the size of the Allied invasion fleet, these losses had no practical impact on the Allied build-up in Normandy. Pictured here is the British frigate Holmes attacking a suspected U-boat off Normandy. McNeill, M H A (Lt), Royal Navy official photographer [Public domain]. For more information on this and other related topics, see The Longest Campaign, Britain’s Maritime Struggle in the Atlantic and Northwest Europe, 1939-1945.

BRIAN WALTER