Your project looks interesting.
This is a Springer type craft of which we have a special section devoted to it. It might be possible to actually build her from the pictures that you have. The end and side views could be scaled up on a computer to give you some measurements and the rest could be scratch built.
Also it might be useful at the building stage to fit a prop shaft and rudder for when you feel ready to electrify her.
Cheers
ken