Western Approaches local escort: British destroyer HMS Westcott (D 47) (LtCdr W.F.R. Segrave, RN) and corvette HMS Gladiolus (K 34) (LtCdr H.M.C. Sanders, RNR)
Joined section HX-65B as reinforcement on 26 August: British sloop HMS Lowestoft (L 59) (Cdr A.M. Knapp, RN)

* U-boats that fired torpedo or used the deck gun

On the evening of 24 August, the main convoy HX-65 split with 20 ships proceeding to Methil in section HX-65A and 25 ships proceeding to Liverpool in section HX-65B.

As HX-65B proceeded southeast it encountered the submerged U-57 on the morning of 25 August. HMS Westcott picked up a ASDIC contact and carried out two depth charge attacks, but they were some distance away from U-57 and the destroyer soon rejoined the convoy. Throughout the day, six tankers could not keep up with the main convoy and slowly fell astern despite the attempts of HMS Gladiolus to round up each ship during the evening. In the meantime U-57 had caught up with the convoy, sighted the large tankers trailing less than a mile behind and attacked the closest straggler from the starboard beam, sinking the Pecten. In the ensuing counter attack the U-boat dived to evade the escorts that were converging on the sinking tanker. HMS Gladiolus first attacked a doubtful contact on the port quarter of Pecten and then changed to the starboard side where she was joined by HMS Westcott. Both escorts obtained a good contact on U-57 and attacked with depth charges, but the contact was lost after this initial attack and could not be regained despite further intensive searches, allowing the U-boat to escape undamaged. As they were the only escorts, both warships soon had to leave to rejoin the convoy and safely brought the ships to their destination after HMS Lowestoft joined as reinforcement on 26 August.