Joint Statement with Churchill on Anti-Submarine Warfare.
During the month of July very poor results were obtained by the U-boats from their widespread effort against the shipping of the Allies. The steady flow of trans-Atlantic supplies on the greatest scale has continued unmolested, and such sinkings as have taken place in distant areas have had but an insignificant effect on the conduct of the war by the Allies. In fact, July is probably our most successful month, because the imports have been high, shipping losses moderate, and U-boat sinkings heavy.
Before the descent upon Sicily an armada of warships, troop transports, supply ships, and landing craft proceeded through Atlantic and Mediterranean waters with scarcely any interference from U-boats. Large reinforcements have also been landed on that island. Over 2,500 vessels were involved in these operations and the losses are only about 80,000 tons. On the other hand the U-boats which attempted to interfere with these operations suffered severe losses.
Our offensive operations against Axis submarines continue to progress most favorably in all areas, and during May, June, and July we have sunk at sea a total of over 90 U-boats, which represents an average loss of nearly one U-boat a day over the period.
The decline in the effectiveness of the U-boats is illustrated by the following figures:
In the first six months of 1943, the number of ships sunk per U-boat operating was only half that in the last six months of 1942 and only a quarter that in the first half of 1942.
The tonnage of shipping in the service of the United Nations continues to show a considerable net increase. During 1943 new ships completed by the Allies exceed all sinkings from all causes by upwards of 3,000,000 tons.
In spite of this very favorable progress in the battle against the U-boat, it must be remembered that the enemy still has large U-boat reserves, completed and under construction. It is necessary, therefore, to prepare for intensification of the battle both at sea and in the shipyards and to use our shipping with utmost economy to strengthen and speed the general offensive of the United Nations. But we can expect continued success only if we do not relax our efforts in any way.
Franklin D. Roosevelt, Joint Statement with Churchill on Anti-Submarine Warfare. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/210328