Hull shapes for Water Plane

Long floats, working as tail booms. So, the same potential issue with too much pitch stability.
I agree that S.65 looks awkward, especially in compare to your design. Anyway, I advice to bend the rear part of floats upwards.
regards
krzys

 

Or use Chance Vought F-8 Crusader wing idea.

 

No, just no...<shudder>....

 

Not in this layout, where wings are also the float struts...
krzys

 

Is a ground effect desirable on seaplane ?

 

Anything that gets the seaplane out of the water as quickly as possible is important. Too many seaplanes are poorly designed for waterborne performance. They need unnecessarily long takeoff distances.
JS

 

Not only is it desirable, it's inevitable.

 

I remember that landing Beaver on flat water, could be tricky because of difficult height assessment. You have to look to the side to during descent. I don't remember if there was anything bad about ground effect.
In my opinion, the wings, propellers should be kept far from the water. Fast and short take-off and landing. Slots, flaps, additional engine and prop. It can be electric although I would prefer some 3 cyl two stroke from jetski.

 

Let say Republic RC-3 Seabee - Wikipedia https://en.wikipedia.org/wiki/Republic_RC-3_Seabee on steroids :
carbon , prop , slots, thrust vector control ,turboprop , folding floats.

 

Trident TR-1 Trigull - Wikipedia https://en.wikipedia.org/wiki/Trident_TR-1_Trigull
Here are some improvements.I disagree with this landing gear.Old ones ar better or could be modified.

 

landing ...easy way to capotage with those foils.