The close formation diagram omits cruiser or battleship forces stationed farther away to answer a German surface sortie. If those forces were too distant, a raider breaking into the merchant formation posed a threat that the escorts alone struggled to meet. Destroyers could form up and drive off heavier ships. One example involves an officer who had previously captained HMS Cossack, later led another flotilla, and received the Victoria Cross after driving off German ships, though such attacks risked several scarce escorts. Surface raiders shaped convoy routes, deployments, and organization even when they never reached the merchant ships. The Atlantic campaign combined submarine, air, and surface warfare.
Notable Point · 18:41-21:12
Distant cover guarded convoys against surface raiders
Cruiser or battleship cover was needed beyond the close screen because destroyers could challenge raiders only at serious risk to themselves and the convoy.