The destruction of U-100 and U-99

Walker was flagship of the 5th Escort Group under Captain Donald Macintyre, who favoured aggressive submarine hunting. U-99 under Otto Kretschmer and U-100 under Joachim Schepke were attacking the convoy, whose losses included the Canadian merchant ship J. B. White. While searching for U-99 on 17 March 1941, Walker and HMS Vanoc found U-100, which sank at 03:18 after depth-charge attacks and ramming by Vanoc. Walker took aboard six U-100 survivors before detecting U-99. Depth charges forced U-99 to the surface, where shellfire damaged her and her crew abandoned the boat. The German account credited scuttling, although the preceding damage leaves open how much difference that made to her loss. Her sinking time is disputed between 03:43 and 03:48. Walker rescued 40 survivors from U-99. The two losses came ten days after Günther Prien's U-47 was lost, removing three prominent U-boat commanders from Germany's campaign in a short period.