Difference between fiberglass and glass covered wood multihulls

[skifinnatic]

I have been doing some research and am wanting to know the difference (pros, cons) of fiberglass multihulls and glass covered wood multihulls. Thanks.

[delmarrey]

The problem with glass covered wood (outside, not sandwitched) on hulls is sturation and wood rot.
On decks it's not as bad due to the water to run off horizonally. But in hulls and vertical structures they tend to soak the wood. And it's better to use epoxy if one is going to glass over wood. One it sticks better, two epoxy will not let water pass thru like polyester.

I'm sure others will pipe in, as well.

[skifinnatic]

Originally Posted by delmarrey

The problem with glass covered wood (outside, not sandwitched) on hulls is sturation and wood rot.
On decks it's not as bad due to the water to run off horizonally. But in hulls and vertical structures they tend to soak the wood. And it's better to use epoxy if one is going to glass over wood. One it sticks better, two epoxy will not let water pass thru like polyester.

I'm sure others will pipe in, as well.

so what you're saying is fiberglass is better?

[Alan Wheeler]

I think design. The older wooden ones ten to be shaped due to restrictions of building material. Pure GRP can be molded in any shape. Slightly aside, pure ply boats, no matter what boat, have a certain feel on the water. The seem to have a life and are certainly lively. the hull reponds quickly to any action on the water. Glass has always seemed slightly dead in response. Glass over ply does sti in the middle of the two. I am not sure you could outright rule GRP is stronger than glass over ply. But certainly molding GRP can ensure certain parts of the structure can be designed and manufactured to be far stronger than timber ever could.

[sandy daugherty]

A WEST system boat is a monocoque composite structure that can be lighter and stronger than a solid glass or foam cored structure, when carefully built by a skilled craftsman. Glass over ply is another story. Delamination is a frequent problem, and water migration through the ply can be terminal. Since this is now a less commonly used form of hull building, it might be fair to say that the bad builds are landfill, and the good builds are still sailing. Epoxy bonds better than polyester resins, but surface preparation is the critical element. This is still true when decks and bulkheads are glass-sheathed plywood. Even vacuum bagging can't escape the need to have a perfectly prepped wood surface.

Glass over wood multis are the greatest thing to hit the boating world since the weighted keel
OK, so maybe I am a bit prejudice on the matter. The pros are, easy to build, easy to work on, cheaper (in my opinion) to build for the home builder.
Cons, Wood rot. Unfortunately, there are LOTS of small inaccessible spaces in a multi hull for rot to happen. Weight. Wood is not light. Glass over wood hulls tend, for the most part, to be heavier, which can be a real issue for multi's.
I admit I have not built or owned a glass multi, only glass over wood, but having owned Fiberglass, wood, and ferro boats, and done major restoration to all, this is the easiest hull material I have worked with.