In March, Convoy SC 121 was attacked by 31 U-boats in two patrol lines. It was the most successful battle of the war for Dönitz. The battle of Convoys HX 229/SC 122 was the largest convoy battle, with 40 U-boats involved. Each operation was successful, but all were fought in the mid-Atlantic. Allied losses reached a peak in March 1943. The Admiralty later issued a report on the matter; "The Germans never came so near disrupting communications between the new world and the old as in the first twenty days of March 1943." Dönitz later conceded the March battles were to be the U-boats' last victories. New Allied techniques, tactics and technology began to turn the tide. By April 1943 U-boat morale was reaching a crisis point. 98 new boats were sent into the Atlantic that month, and although the training was thorough the crews were inexperienced and it showed. 15 U-boats were destroyed in March 1943 and another 15 in April. Werner Hartenstein and Johann Mohr were notable casualties over the course of these eight weeks; the former's decision to rescue survivors of a sunken ship led to Dönitz's Laconia Order, which later formed part of the criminal case against Dönitz.