Floating trailers seem like such a nice idea - until you get the details, where I don't think they work out so well:
- In fresh water, the trailer running gear may not suffer (much) but the trailer now has to be designed with nothing underneath it, unless you think things like black tanks and piping can be immersed.
- Are you happy to tie your egg up to a jetty with the
fiberglass skin rubbing on the timer/metal of the jetty? Sure, you can hang fenders along the side, but how do you do that from the inside?
- A watertight door isn't that far-fetched, but how do you get in and out once the trailer's in the water?
- Few trailers have any 'sitting-out' space that you would want afloat.
- What's the advantage of taking the trailer running gear with you, when you have to leave the tow vehicle behind? I think a simple flat bed trailer with a float-off body would be easier and more useful.
Here are two previous British amphibious trailers and, for the ultimate amphibian, here's a repeat of some photos of an astonishing German folding amphibious one-off.