You need a couple of things;
- hugely powerful engines, which in turn require either excessive overloading of one float with fuel, or contra-rotating props.
- need for long range, which leads to bigger aeroplane, so more powerful engines needed
- floatplanes aren't that seaworthy, so flying boats are better. It is possible to design a clean flying boat hull,but difficult.
With jet engines it becomes a lot easier;
From 1943-44
Type: SR.A/1
Function: fighter
Year: 1947 Crew: 1 Engines: 2 * 1746kg Metropolitan-Vickers F2/4 Beryl
Wing Span: 14.02m Length: 15.24m Height: 5.11m Wing Area: 38.60m2
Empty Weight: 5108kg Max.Weight: 8633kg
Speed: 824km/h Ceiling: Range:
Armament: 4*g20mm
Its fast and fairly long-ranged, but why bother when you have carriers?