Convoy SC130 was the last trans-Atlantic convoy to be seriously threatened by U-boat attack in 1943, and its safe arrival at Londonderry could be said to mark the Allied victory in the battle of the Atlantic. The British code-breakers of Bletchley Park had decoded German messages setting up an ambush, and an attempt had been made to steer the 38-ship strong convoy through a gap in the line of 33 U-boats, but on 18 May one of the U-boats spotted the convoy and the attack began.
Convoy SC130 was protected by a close-escort group led by Commander Gretton of the Duncan, supported by the 1st Escort Group, and with continous long range air-cover provided by Coastal Command Liberators of No.120 Squadron and Hudsons of No.269 Squadron. Five U-boats were lost during the attack – U-209 was sunk by the frigate Jed and sloop Sennon of the 1st Escort Group, U-258 and U-954 by the Liberatores, U-273 by the Hudsons and U-381 by Gretton and the Duncan. No merchant ships were lost.
By the time Convoy SC130 reached Londonderry the Germans had lost 33 U-boats, and that figure rose to 41 by the end of the month. On 24 May Dönitz had admitted in a report that U-boat losses had risen to an unacceptable level. The wolf packs were withdrawn from the North Atlantic, never to return in strength. The battle of the Atlantic would continue into 1944, but after the battles of May 1943 the Allied victory was rarely in doubt.