Hello,
Information from elsewhere indicates that the German steamer "HOCHHEIMER" was despatched at 0037 on 20 May 1944, in position 43:31N:02:52W. Fail to see connection with loss of No.53 Sqn Liberator BZ873, lost sometime after 0120 on 21 May 1944.
https://uboat.net/allies/warships/ship/3434.html & ADM 199/1841
Col.