HX 112 and the fall of U-99 and U-100

On 17 March 1941, Walker and Vanoc removed two leading German U-boat commanders from the Battle of the Atlantic during the defence of convoy HX 112. Sustained hunting forced U-100 to the surface, where Vanoc rammed her at about 03:18. While rescuing six survivors, Walker detected U-99, broke off the rescue, and attacked with depth charges until the damaged submarine surfaced and surrendered. U-99 was scuttled at about 03:43, and forty survivors were rescued. Walker is estimated to have used roughly a third of her official depth-charge allowance in the attack while carrying substantially more than that allowance. A later, more detailed account of six U-100 survivors corrects the earlier tentative recollection that she was lost with all hands. Reunions between U-99 survivors and Walker's crew began in 1963, with Macintyre as a chief organizer.