I have an excellent book on fiberglass repair. Sailboat hull and deck repair By Don Casey International Marine/Ragged Mountain Press A division of McGraw-Hill McGraw Hill has an 800 number for ordering it 1-800-822-8158 Their address is PO Box 547 Blacklick, OH 43004 USA I just completed an extensive rebuild of a fibreglass Fireball. Some of the work I did with epoxy. The principles are the same but you can't gel coat like the fiberglass.

I have recently constructed a foam sandwich Fireball hull in a female jig that was designed to build stitch & glue ply fireballs. The jig was constructed from steel some years ago and measures exactly to the rules without any tolerances. The method I used was to lay all the panels in place and stitch them together with poly cord then glassed the inside of the hull. the next step was to fit the bulkheads and all of the interior framework, followed by glassing the underside of the deck panels before gluing them in place. The outside of the deck was then glassed and the hull was removed from the jig and turned over for fairing and glassing out side. I feel that this method could be simplified by glassing one side of the foam hull panels prior to placing in the jig as in stitch & glue. This would speed up the fairing and finishing process of the outside of the hull. It was very easy to keep the hull under minimum weight even though I probably overdid the strength and stiffness bit a little as this was the first Fireball I have built.

Ok guys, that is enough of that. The foam in question is an illegal building material. The foam must be RIGID CLOSED CELL, and CROSS LINKED. This means that the foam can not have a short strand orientations, as does blue board. Furthermore, the density and is way off, and it is far from rigid. Lastly, it must be sandwich construction meaning laminates on both sides of the foam. Again, chopped strand mat (CSM) has a low structural integrity, it difficult to fair, and is heavy for it's relative strength. With that said, the rest of it is not a bad idea. I read the trail above me ( I am assuming your are in Australia) and have seen a couple of boats built from this method. Seem to be stiff enough, but a little push test showed weak laminates on the hull and topsides. It appears as though more glass went into the deck than the hull. The foam is the key in laminate construction. Some builds have found that using really light foam results in a light boat. Wow, rocket science. However the density of the foam (and it being cross linked) determines a good part of the overall stiffness of the panels. So when builders go to lighten a boat they tend to skimp on the core. Then, they go and put thin laminates (to keep it more light) often of the wrong fiber orientation. Take some notes from hier Winder. Use a good foam. Don't skimp-- 4-6mm in low stress areas right up to 10mm elsewhere. Just like an I-beam the thickness of the foam helps to determine the stiffness of the panel. Then use S-glass (6oz min) or directionally oriented e-glass (6-18oz) using CSM only for bonding or veil purposes. Caution to glassing before jigging- this will cause panel deformation over time as the glass desperately tries to relieve the stress by bending back to flat. For the one off kind of guy out there do one side, then the other. However- a female mold is what works best, using a vacuum bag set-up. The molds can be done effectively enough so if you have 6-8 boats wanted and a plug you could save time and money if your have a good and experienced glass worker.

Over ten years ago two foam core hulls were built in NZ using a male jig. Basically foam sheets (not sure of the specifications - but I do know they used good quality divinicell foam) were fastened to the jig and the outside "glassed" (I think they used a mix of kevlar & s-glass). Hulls were then carefully removed from the jig, inside laminate, tanks and bulkheads and deck (all foam cored laminate) were fitted. The boats both came out under weight (the lighter of the two required around 7lb of lead). The hulls have remained stiff, down to weight and very competitive. One of the guys who built them has since built a wooden hull. His comments are the composite hull was a lot easier to build, the male jig was relatively easy and inexpensive to set up and this is certainly the way he would go if he every built another hull. He does have quite a collection of photos of the construction of these hulls -f anyone is interested.

I also had an old Rondar which I tried to fix up. My hull was a laminated foam core with about a half inch thick layer of Airex foam between the bottom and the cockpit floor. When I weighed the hull it was way overweight (about 250 lbs.) and I soon discovered why. The foam core was waterlogged in the entire cockpit area. I cut out the inner layer with a sabre saw and then scraped/chiselled all of the foam out of the cockpit floor and then re bonded new foam in and glassed this over. This was a lot of work and not much of an improvement, as the hull was still waterlogged under the decks, where I couldn't get at it. I eventually abandoned it and built a new wood hull, which at about $1,000.00 for the raw materials, was not much more than it would cost to re-glass. A good compromise might be to build a female jig to hold the hull, then cut out and throw away the fibreglass decks, bulkheads, cb case etc. and build a new wood decked boat in the glass hull. If the hull is foam cored, grind out all the foam and replace it with wood stiffeners which won't soak up water and, unlike the foam cores, do not need to be vacuum bagged to get a good bond to the hull.