If you don't mind the little dots of foam that flake off when using the stuff, blue foam insulation from the local building supply will work for a ww boat. Not nearly as nice as minicell or ethafoam to work with, but lots cheaper and more readily available. Liquid Nails will do as an adhesive for wall construction/assembly. Build the wall at least two inches thick, more if you want. Three inches is certainly enough.
Resin is good for installing the walls once you have them well fitted. Liquid Nails will work, too. It just won't let the walls slide in as well, that's all. Use bricks or sand bags to "clamp" the hull and deck to the walls until the adhesive has dried. Test the wall for stability. If needed, reinforce with small blocks of foam to make sure the wall will not slip and collapse. The wall needs to be solidly attached to the hull and deck.
If the little flakes are too much for your tastes, build the blue foam walls anyway and use them as patterns to avoid waste when cutting minicell.
Consider adding blue foam struts to support other areas of the flimsy deck. Build struts from the bottom of the center wall to the "quarter deck" if you want. (Think in terms of the old-style trestle bridges.)
If you have the old walls, check them for fit while they are in the boat. If OK, use them as a pattern for cutting the new walls. Try to adjust the fit before cutting and shaping the new walls. However, if you want to make new walls, I suspect the old ones are among the missing.
Without the old walls to use a pattern, you will have to make your own pattern. You can try the "high noon" method (light bulb above the suspended, rotated 90 degrees, boat. Trace the shadow cast on brown paper placed below.) This never worked well for me, so I like this method:
Use a carpenter's square, a roll of brown wrapping paper, and a steady-handed helper to hold things level, plumb, and still while you do a tracing of the hull and deck centerlines on a paper covered flat surface (floor) while guiding the square around the outside of the boat with the horizontal edge on the floor, and the vertical edge touching the boat. Your sharpie pen should be held next to the outside apex of the square.
Do you have a workshop big enough for a ww boat, or is this a living room project? (Remember that glasswork needs sixty degrees or more to go anywhere near right.) Sanding glass laminates is outside work, no matter what the weather. If using an attached garage, know that glass dust (and to a lesser extent, resin fumes) will permeate your home for years. Protect your lungs and eyes from contact with resin, fumes, or glass dust. Skin protection is a good idea, too. See John Sweet's website for information on how to do this. Do not skip this step! REALLY!
The flimsy deck may be a cause for concern if you decide to re-seam the boat (outside seam, that is.) Depends on how steady you are with a grinder because you need to grind down the old outside seam to "bare" cloth to get the new seam to adhere. Hand sanding using auto body papers and quick-switch sanding blocks is the only reasonable alternative, and will take a while for a ww seam. Using an electric drill with a sanding disc is a good way to ruin a good drill. In addition, if the drill is old enough to be used to sand fiberglass, it probably will be a bitch to control well enough to avoid gouges that will make the re-seam job go bad in a hurry. Remember, you were warned!
I would duct tape the bow area delamination, and unless the split seam areas are flexing and stressing the inside seam or leaking, I would go with high quality duct tape there, too.
Testing split seams (or other delaminated areas) with a steel pocketknife blade is the way to determine if glasswork is needed. If the laminate yields, crumbles, or holes out when firmly prodded, it is time to get out the resin and cloth.
Checking for leaks is a good idea, too. That way you will know where a glass repair is needed!
Tie the vertically inverted boat to something like a telephone pole or a tree. Leaning it against a wall or building will work, but make sure the boat is well secured to prevent it falling to the ground.
Use the garden hose to fill the inverted bow or stern with water. Look for little streams of water along the seam line and other areas of the laminate that have been "wounded." Mark the leaks with a grease pen or marker.
Empty the boat and do the other end. With a ww boat, this is a lot of weight, so be careful not to let things get out of hand.
Probe the marked areas with the knife blade. Proceed with repairs as needed.
Aren't glass boats fun?
. The seams need work so I'm thinking of cutting it at the seam, adding a couple of layers of glass inside both deck & hull, then re-seaming. Would this sufficiently stiffen the boat or am I nuts?
), or keep that one as-is and look for a newer, stiffer one in more of a training layup.
