Four of the "Black Cat" Catalinas, that carried out the "Double Sunrise" service between Perth and Ceylon (Sri Lanka) during WW2, were scuttled in waters somewhere between 40 and 200M deep, some miles off Rottnest, in late 1945 and early 1946.
Their precise location is unknown, despite numerous eyewitness reports. The fifth "Black Cat" was scuttled in waters off Sydney a few months later.
All the Black Cats were sunk by the use of explosives, resulting in massive damage to the aircraft, breaking them into many pieces.
The W.A. Maritime Museum was tasked to investigate the possibility of finding and raising at least one of the Black Cats for the Bullcreek Aviation Museum.
A study on the feasibility of this scheme was carried out - and while it was deemed feasible the wrecks could be located, the potential of being able to raise anything even remotely recognisable, and being able to conserve it, was regarded as being very low; and the entire proposal was recommended against, and was not proceeded with.
Black Cats - Report on the feasibility of locating, raising, and conserving one of four Catalinas
The Black Cats Recovery Report