Why submarine success cannot be read from sinkings alone

A substantial aside challenges the assumption that Germany should simply have transferred capital-ship resources to submarines. First World War U-boats came closer to a strategic decision partly because anti-submarine warfare was still developing, whereas the Second World War Allies built intelligence, escort, and hunting systems that generally kept pace. The rise in 1942 sinkings shows why operational context matters: escorts and hunting groups were diverted to protect Operation Torch convoys, temporarily weakening other routes without making each U-boat intrinsically more lethal. Histories centred on attacked convoys can also obscure the many sailings that passed without contact.