Fiberglass constant camber

[Briggsm]

Is it possible to build constant camber with grp instead of ply? I know it would be heavier but you would have a glass boat when your done. If this is a stupid question forgive me.

[jehardiman]

Yes, but why? As you point out, it would be heavier and it would not be exploiting the properities of glass; i.e. being able to make compound curvature in a solid panel. Constant camber designs are built around the limitations of sheet products and exploit the sheet size work savings. There is nothing to be gained except possibly an easier to construct mould and the flip side is that it will take you just as long to lay up a structuraly "sub-optimum" panel.

FWIW, epoxy coated cold molded constant camber panels are as weather resistant as glass for the useful life (30+ years) of a boat.

[catsketcher]

Dick Newick did something like this for Gulf Streamer in 1974. The moulds could do both the float and main hull. This works fine on nice thin Newick hulls but may not otherwise.

The reduction in fairing would be a good reason to use this technique. I have sometimes thought of it to produce a slightly more curvaceous hull than Kelsall's KSS. It could be done and would be a good way to save time if it did not compromise the shape too much.

In the end Chris White used different panel shapes called Varicam rather than constant camber. This gave the mould different curvatures along it so that it was not constant.

The amount of fairing in modern composite cats is ridiculous. Whereas fairing was something that was only (quickly) done on the outside most time fairing is in deck fittings and even more time is spent inside. If you vac bagged the laminate and produced large but well designed hull sections you could save thousands of hours of work in the fairing of a large cat.

Fairing is an example of cost shifting that designers do. Some designers make nice flowing shapes and then leave it for the builder to put thousands of hours into fairing them. There is a reason that experienced builders like Denney, Kelsall and Snell make easy to build boats using time saving techniques. The problem to me is that producing a glossy interior takes more time than building the structure.

cheers

Phil

[Briggsm]

phil,
That is exactly what I was thinkin'!