<P> Late in the war, the Germans introduced the Elektroboot: the Type XXI and short range Type XXIII . The Type XXI could run submerged at 17 knots (31 km / h), faster than a Type VII at full speed surfaced, and faster than Allied corvettes . Designs were finalised in January 1943 but mass - production of the new types did not start until 1944 . By 1945, just five Type XXIII and one Type XXI boats were operational . The Type XXIIIs made nine patrols, sinking five ships in the first five months of 1945; only one combat patrol was carried out by a Type XXI before the war ended, making no contact with the enemy . </P> <P> As the Allied armies closed in on the U-boat bases in North Germany, over 200 boats were scuttled to avoid capture; those of most value attempted to flee to bases in Norway . In the first week of May, twenty - three boats were sunk in the Baltic while attempting this journey . </P> <P> The last actions in American waters took place on May 5--6, 1945, which saw the sinking of the steamer Black Point and the destruction of U-853 and U-881 in separate incidents . </P> <P> The last actions of the Battle of the Atlantic were on May 7--8 . U-320 was the last U-boat sunk in action, by an RAF Catalina; while the Norwegian minesweeper NYMS 382 and the freighters Sneland I and Avondale Park were torpedoed in separate incidents, just hours before the German surrender . </P>

The battle of the atlantic was won by the allies for all of the following reasons except