UK underwater weapons drifted 1945-80, for little payoff. NSR 7511 Mk.24 Tigerfish was deployed after 22 years’ work at Lucas, Plessey, Admiralty Establishments, eventually Primed by Marconi. It was firstly for ASW, so due to his "need for confidence” HMS Conqueror's CO attacked Gen.Belgrano with his reload store, USN Mk.8, designed in 1927. Cancelled projects had such codes as Bootleg, Dealer, Mackle, Nozzle, Pentane, Zeta/Zonal/Zoster. To carry such things Gannet emerged from a 1945 Spec.
The fly-before-buy process v. Blackburn Y.A.1 overlapped outbreak of the Korean War: a modest RN able to crew just Triumph at sea in December,1947 was funded for Strike carriers Victorious, Eagle, Ark Royal, and new Light Fleets Centaur, Albion, Bulwark, Hermes. ASW flights would be formed from 100 Avenger A.S.4/5, then Gannet A.S.1/4. No ASW carriers: RNVR would provide convoy escort on the Colossii Light Fleets, with, ah, functional Seamew A.S.1, supplemented inshore by RAuxAF Seamew M.R.2, 30 each, part-MSP-funded. Some Gannets were cancelled, but FAA took delivery of (32 T.2/8 T.5), 146/A.S.1, 67/A.S.4, all part-US MSP-funded (Putnam numbers).
The reported cause of early deletion of RN ASW Gannets was to re-assign carrier capacity to Strike and to redefine surface fleet tasks, by putting ASW rotorcraft on piquets. Not only but also? Might 5 carrier Flights of 4 or 6 have been at sea concurrently: a run of 43 was enough to support that on AEW.3. Did US part-fund so many Gannets to sustain a shore-based, ASW/minelaying role overseas? Did that lapse because Gannet could lift endurance or payload. A.S.1, delivered 1955/56, were scrapped from February,1960, A.S.4 delivered from August,1956, withdrawn by July,1960 and scrapped from December,1960 some with little more than delivery mileage. RAN flew them to August,1967 alongside Wessex HAS.