British interest in attacking ships in harbour grew out of the German fleet's shelter during World War I. The scenario treats a Taranto-style strike as certain because harbour attacks had been part of British doctrine since 1932. Tension-wire arrangements on aerial torpedoes addressed the harbour-attack problem. At sea, allowing a torpedo to dip after entering the water and then rise to its operating depth could help it cope with waves. Applying the harbour arrangement there could make an attack more complicated.
Notable Point · 1:28:33-1:29:33
Harbour-strike doctrine and aerial torpedo entry
British interest in attacking ships in harbour shaped Taranto planning and torpedo techniques that were less helpful at sea.