Only seven German submarines covered the area while numerous British destroyers moved among the evacuation ships. Lingering torpedo problems after Norway changed a U-boat commander's risk calculation because a failed shot could reveal the submarine to nearby escorts. A small destroyer was a poor target unless the chance of success justified exposing the boat, while larger transports were harder to find across the dispersed operation. The suggestion that German submarines had orders to let the British escape also conflicts with the Luftwaffe's continuing attacks on the same shipping. Weapon reliability, escort density, target value, and commander behavior offer a stronger explanation than a single restraining order.
Notable Point · 1:02:31-1:03:38
Why the U-boats missed Aerial's shipping
Limited submarine numbers, unreliable German torpedoes, and the presence of many destroyers help explain why Aerial's shipping escaped a stronger U-boat attack.