Specialized British escorts and a flexible fighting screen

Bramble, Hyderabad, Rhododendron and the trawlers formed an anti-submarine layer, while Sherbrooke's O-class destroyers and Achates supplied the surface-fighting screen. Keeping one older A-class ship among four O-class ships gave the formation a natural vessel to leave with the convoy when the main group intercepted a threat. The similar ships could then maneuver together while the detached vessel continued protection of the merchants. That arrangement gave commanders an option rather than prescribing every detachment. Vian took Piorun into the attack on Bismarck despite her differences from the rest of his destroyer force.