Convoy HG-76 — the escort under the wolf-pack

Frederic Walker is 48, with most of his career behind him. He joined the Navy as a cadet in 1908 and, after the Great War, became passionate about anti-submarine warfare — only to watch the interwar years dismiss his speciality as a useless obsession. To the Admiralty the submarine threat was marginal, and men like him were tiresome theorists. He was left to grow bitter behind a desk.

In late December 1941 he is finally given a command at sea: escorting convoy HG-76 from Gibraltar to Liverpool. Out in the open ocean a wolf-pack of U-boats clings to the merchantmen, day and night, certain of its impunity — between June and October 1940 these packs sent 270 Allied ships to the bottom, and the Royal Navy holds to a strict defence. The doctrine is set in stone: an escort protects its ships by staying with them, never breaking away to chase the enemy.

But Walker has sloops faster than a surfaced submarine, and a conviction hardened during his years in the wilderness. He can tighten the screen around the merchantmen and absorb the blows as the rule demands; he can instead send his sloops far from the convoy to hunt the U-boats, forcing them to dive so they can be run down; or scatter the convoy and call for a reroute to try to shake off the pack.