Harbor-attack planning before Taranto

The exact origin of the Taranto plan is disputed, but the Royal Navy already held detailed information about the harbour before the Abyssinia Crisis. Its operational ancestry reaches back to First World War plans for Sopwith Cuckoo attacks on ships sheltered at Wilhelmshaven. Those plans influenced work on Eagle, Hermes, and Furious, and postwar committees continued studying harbour attack. The mature concept was a surprise night strike against a concentrated fleet when its defences and crews were least prepared. Harbour depths and profiles were publicly obtainable, yet long-term collection turned ordinary hydrographic data into operational intelligence once war made Taranto a target. Systematic collection and current records mattered more than secrecy.