Soft shell multilayer hull with aluminum frame

[nathanica]

Hi,

I'm new on the site, so I don't know exactly how things are done here but I've been reading and studying up on boat design as a hobby and am especially interested in experimental boats with replaceable parts. I was wondering what the more experienced members (that would be everyone here) might think about a soft shell hull design I thought of.

The boat would begin with an aluminium tubing frame set at the chines, followed by aluminum wire mesh stretched over the frame. On top of that would be stretched 4 more layers: rubber sheet for water-tightness, fiberglass cloth (without epoxy) for strength, another rubber sheet for more protection and finally a layer of metalized mylar for UV protection of the rubber. Finally, the mylar could be coated with a few layers of wax for scratch protection and hydrophobia.

As a novice, it seems to me this would make a pretty resilient shell that would hold up well to the elements and that would be well suited to experimental hull shapes.

Thanks for all your input!
Nathan

[rwatson]

Novel concept, but too tricky in practice. The final Mylar layer would have to be a perfect fit (technically difficult to build) to avoid bagging and stretching away from the other layers, and one perforation would mean a whole boat skin full of water sloshing around between the layers. Fibreglass cloth would just tangle up like fishing line be made a mess with the 'working' of the other layers, and the ends would be impossible to fasten to rigid parts of the frame.

I have seen a trimaran that was built on a frame, chicken wire stretch across a-la ferro cement, but then foam was tied to the inside of the wire, and GRP on the outside glued the wire and foam into one unit. It saved having to do a full size wooden frame.

[duluthboats]

nathanica,
You did not say what size and type of boat you are thinking of. The method you describe seems to be a lot of work for what in the end will be a rubber skinned boat. The glass used in this way will only add weight.
Building small test boats is usually plywood panel and seam for hard chine or wood strip with or without resin and glass skin for round chine. There is also skin on frame with wood being used for the frame with some type of fabric stretched over it and a coating for UV and water resistance. All of these methods will give you better results at less cost and work when compared to your method.
Gary