Despite the losses suffered by Rossbach and poor results achieved during its attack on SC 143, and still believing their new weapons and tactics gave them an advantage, BdU (Befehlshaber der Unterseeboote Commander of the Submarines) re-organized the boats then in the North Atlantic into patrol line Schlieffen with the intention of intercepting the expected west-bound convoys.

When Allied intelligence learned of the position of Schlieffen, Western Approaches Command decided to seek battle, increasing the defence by joining the two convoys and their escorts, and sending B-7 as reinforcement.

By evening a number of boats were in position and commenced the attack, which became one of the most calamitous of the entire campaign for the U-boat Arm (U-Bootwaffe, UBW).

The only success for the Schlieffen boats that day was when U-426 sank the freighter Essex Lance, which was straggling from ONS 20.

The convoys made a drastic alteration in course, to shake off any shadowers; this was successful in that BdU received conflicting reports from U-91 and U-413, leading to Schlieffen being sent in the wrong direction.

Schlieffen was unable to re-gain contact and in view of the losses sustained BdU ordered the group to retire.