Been turning this over in my head and can see all the issues you face with traditional gear....

Then I remembered seeing a pics of a hobie that had the beach wheels set into the hulls as a fixture, this was several years ago that I saw it and I have spent a couple of hours searching for those images again but with no luck....


From what I can recall, he cast a basic box into the bottom of the hull and then made a 2nd box that held the wheel and this box slid inside of the cast in box.... add a bit of silicone and it was installed and sealed.

the only images I could find are largely from aircraft wheel pants or wheel spats

but you get the idea....







I'm sure you could design a simple yet effective setup that would work well, I don't think that the exposed tyre would cause that much grief if it was set in to minimise water turbulence ......
it would also mean no more lost/stolen beach wheels or exotic Lamborghini style door hinge setup so you can fold the wheels up onto the deck and take up room etc etc etc etc .....

just thinking out-loud