Foam core composite construction for Wheelhouse panels

Can anybody suggest a light weight but strong Panel construction comprised of Foam (material type?)/Composite core fiberglass resin, gelcoat (not epoxy) laminate that works for construction of a small wheel house 5'X7'X6'6"H. I am picturing some type of core material sandwiched between fiberglass/resin. gelcoat, structurally reinforced with wood frame.

Worst case scenario, 1/2" plywood, laminated both sides with fiberglass resin. Is this strong enough for a wheelhouse structure? To be used in Nome, AK. Wind, rain, etc. Im trying not to design this being comprised of 3/4" Marine Grade plywood to save weight. Idea here is low-weight. Exact materials required? I want to pre-build and assemble in the field panels by bolting together

Pieces bolted together to form structure with no supporting structure. basically 2'X4' panels,,,cut openings for windows, etc. Any suggestions? thank you

 

Dimensions and max weight of box are important as well as the displacement and vessel weight, etc.

 

Fallguy, I noted on my original post dimensions 5 ft x 7 ft x 6'6". don't need weight estimates at this point. Just need the info requested. thanks

 

The walls could be made with 12mm foam and 12 oz glass. Or 1/4" ply with 6oz woven.

The weights per 32 square feet are as follows.
Foam vac at 70% resin weight
15.7#
Foam hand lam at 100%
17.3#
Ply 1/4" hand lam at 100%
28.6%

All seams would require glass tapes of about 2x4" staggered. Panel weights do not include gelcoat or seam tapes.

the rooftop depends on if you intend loads like radar and how you intend to support it, etc. a rooftop of say 1/4" ply with 12mm foam and 17 oz biax on top would work supported by beams, weight is 39 pounds per 32 sqft plus the beams

You don't really need any wood on the walls for support, but the top needs to have something or be made stiffer(thicker) than I suggested without and it also changes if you want it walkable. Wheelhouses are all about weights and loads unless you are putting it on a barge in which case you would not have started asking for lightweight.

If you build it with 1/2" ply no glass, the weight is 47# per 32 sqft.

 

Fallguy, a big thank you for your informative reply!!...... First, please excuse my numerous Newbie questions, I am learning thanks to the efforts of the persons on this forum. A few follow-up questions if I may with regard to my Gold Dredge Pontoon work boat (8'X26') for use in Nome, AK. Specifically, fiberglass Wheelhouse construction (4'X8') pre made wall panels - need functional, not pretty.

Given that: A) Main requirement is pre-made panels for fast and easy setup/ disassembly for winter storage in the field (let's say 2' X4'). Wall panels bolt vertically to deck,and to adjoining panels, exterior seams to be temporary sealed with silicone caulk, some panels w/ cutouts for windows B) The deck will consist of a single glassed Marine 3/4 ply. C) will need structural additions (wood glassed in place?) to wall panels on interior for bolting in bunk, cabinet, console, etc.

Questions:
1) What is the best way to make panels joinable at floor and sides, flanges? If Yes, what do you recommend for a flange? OR another method I'm missing?
2) What is the best method for interior attachment points? glass in wood for screw/ bolt holds? other?
3) With regard to your previous information post, you mentioned, "Foam, 12mm, 12 oz, hand lam at 100% resin weight."
What foam (Product) do you recommend? 12 oz - do you mean chopped strand matt or woven?
Are we talking epoxy resin? or polyethylene resin ( can I go with polyethylene gelcoat after epoxy has cured to save cost)?.......... APOLOGIES, again Newbie here! )
4) Any good books I can buy with regard to fiberglass construction techniques?

Thank you in advance for your guidance, sir!

 

Foam core sandwich construction is not really designed for disassembly. It can be done, but it is a lot of work because the foam is not designed or laid up for off and on..

I recommend you pay the weight penalty and build in half inch Roseburg marine ply and seal all the edges with a wrap of 6 ounce fiberglass and epoxy. To do so, put a radius just less than the ply thickness with router before glassing. Despite Roseburg's claims and ratings; it edge delams when exposed. Other plywoods will as well.

Use some 2x2s; and epoxy them to the plywood and they will bolt together on the corners. Coat everything with 3 coats of epoxy including the 2x2s. Then paint with a primer and a topcoat.

You can seal all your joints from the outside with inner tube rubber or seam caulk.

I did not understand you needed to disassemble each season. Making foam panels robust enough for that is really not something I recommend. The labor and time expense are trouble.

The other issue is theft. If you spend countless hours building foam panels and you arrive in nome and the panels are gone; hard to replace. You can replace plywood panels easier.

All this said, an 8x26 pontoon styled vessel is light on available loading. I don't believe you have enough to support persons, gear, wheelhouse.

I strongly suggest you do some more homework on the vessel. Each pontoon will provide a certain amount of loading. My hunch is for the small footprint of 8x26; you need more like 4 toons.