I have seen that an LCT mk2 or 3 would fit the bill, this is a largish craft but more of an LCM with curved sides than a ship with bow doors.
We happen to have some large card boxes at home and I have commandeered one to cut up and make a mock up.
As we need size and a joint somewhere, it looks like a 4 foot hull and an 18 inch rear would be ok. I have just about enough tanks,jeeps,trucks and a half track to make the well look busy, and the 18 inch rear allows machinery fit with no space probs. The width is approx 12 inches, giving an 8 inch well width and two inch fat sides, I think that 4mm ply should be fine, there is not much curve or sheer, and if the side pieces were cut with the outer grain running vertical instead of lengthways we should be in business. The rear as far as I can tell mirrors the front curvature, but i have not done any research yet.
It will be a flat bottomed craft, ie a waterline model, I should think about 1/2" draught or so. It would be nice to have a retractable drive arrangement for storage purposes?? will put thinking cap on.
I have it. A small recessed box could hold a universal joint, driven from inside by a short proshaft, sealed of course, and the driving propshaft could have a bolt-on arrangement, via a skeg with studs in, the splined end on the removable shaft would plug into the recessed u/j, be slid into place and the studs wingnutted from the inside. Rudder can just pull out, using a nylon tiller arrangement. Or I have some meccano gears?? Hmmm
Ashley