pagen01: I don’t believe Canada (or Oz) acquiesced in UK “passing” Shark or anything to them; nor do I believe favouritism, Blackburn v. Fairey, nor materials prioritising conflict – for to be land-based or to be carrier-based types, was the cause of Shark being displaced by Sword/Blackfish. It was the higher priority of work on heavy Coastal Area boats.

Sunderland was not intended to be what it became – core to 1959. It was chosen as quick, easy adaptation from Empires, to be built in new Harland and Denny yards as coursework for conversion from maritime to aero techniques (the new Boeing Vancouver plant, whose staff was not so much aero-diluted as aero-alien) was given Shark as its mock template simply because 7 had already been bought from Blackburn: a convenient exercise, to lead into the proper type, which emerged as Canso). Bespoke-MR inshore and deep water types would soon replace Sunderland. They emerged as Saro Lerwick, and Saro/Short Shetland. Short-at-Rochester was to build Stirling and would be well-poised for a Super-variant. The best laid plans…I recall a pic of part of the Sydenham site which was evidently Shetland-specific.

Blackburn’s retractable hull B-20 lost to Lerwick, but it was that design which caused Blackburn to be Supervisor of the Air Ministry’s Rhu Agency Factory administered by Denny, into which Botha was assigned to liberate Brough to do the higher priority MR type.

Swordfish businesss success was determined in part by engine-sourcing logistics, and in part by RAF’s airborne torpedo… which was awful. No Long Lance, this, but a frail device demanding precise entry speed/angle, for which Swordfish was seen to be suitable (not necessarily moreso than, but no worse than, Shark). Hence replacing one “obsolete” biplane with another: an autogiro-with-payload+range would have been ideal. So the sequence of events was: Bristol’s Accrington Agency Factory set up to build Pegasus; Blackburn manifestly out of their depth in original design (Botha/Roc/Skua), but well-orientated to Fly Navy; Fairey tasked with the attack type, Barracuda, around which funding had been secured for the 6 Illustrious; Agency Factory constructed at Sherburn to build the Torpedo-Spotter. That hand of cards came out in 1938, very logically, as:
– Blackburn to manage Sherburn, under nominal Fairey Supervision, to build Blackfish, with engines trucked over from Accrington;
– Blackburn to be UK Sister Firm for much/most US acquisitions for FAA;
– Fairey to attend to Swordfish’s replacement, Albacore, and to Barracuda.