Here is a post I carried over from the old Board. The origanal message was posted by"dreadnaught".

hi guys,
brand new here. just starting to consider building a model to do just combat on the waves! much to learn, it appears. one thing that stunned me was the lamination schedule of some builders doing a 'glass hull. i mean one guy was doing two layers of 6oz over 1/4" ply; another 10oz(!). using CA glue for lay-up! now, i'm building a wood/glass kayak(full-size for my use) out of 4mm(3/16") ply and one layer of 4oz. PLENTY strong. i would think 1/8" ply, a layer of 1/2oz mat, & a layer of 3oz cloth with vinyl ester resin would be just fine; and i'm talking about a 1/72 scale WWI battlewagon of approx. 8' length.
what ya think?

You are thinking of 1/8" ply, a layer of 1/2oz mat, & a layer of 3oz cloth with vinyl ester resin would be just fine; and also talking about a 1/72 scale WWI battlewagon of approx. 8' length... humm... an 8 foot long model is very big! What do you mean when you say "just combat on the waves!"? Are you thinking of having your model shoot BB's? Or are you going for just a "scale" model?
As far as the lay up of the hull... if you are going for justa scale model then two layers of 6oz and the 1/8" ply would do fine for a model that large. Epoxy finishing resin would also work great. You can also thin the final coat of epoxy finishing resin with isopropyl alcohol. This will give you a very smooth finial finish requiring very little sanding. Remember to rough up your final coat after it dries with 400 grit to ensure the paint sticks!

I have been asked many times "How do I fiberglass my hull?" This can be a scary thing to do if you have never done it before. In order to take some of the worry out of the task, I welcome you to review the write-up I did at the following link:

Fiberglassing a Hull

Talking about an all-glass hull, or just laminating over the wood for water proofing?
For the latter, lightest I've done is 1/2 oz (!) cloth over 1/16" basswood (a PT boat, and yes it's light the way it should be!).
For all-glass, I think many of the builders use the same rules of thumb for small hulls as for 10 foot battleships. For the BB, the hull must work like a beam, especially when being handled out of water, supporting some 140 lbs... needs lots of glass.
Not such an issue for smaller (3 ft?) hulls... just look at any vac-formed ABS hull, and how flimsy it is before it's built up. But once decked over, and possibly braced internally, it's plenty strong enough.

I haven't built up an all glass light weight hull yet, but just look at hulls from Microglass to see how thin and fine they can get.

Patrick Matthews