making floor in a dinghy

[sigurd]

Hello all,

I need to make a new floor in my 10ft With motor dinghy, since I cut out the old one. It was made with cross ply and glass and the ply had rotted.

I am thinking of filling the bilge with a mixable or bottled foam, cut and sand it down and then putting a layer of glass mat with polyester over that. What kind of foam could I use?

I guess I could also use a sheet of foam, and put glass mat on both sides, I am not yet sure what would be the easiest, cheapest and lightest way to do it. There were bulkheads (plywood/glass) every 40cm or so in the bilge to stiffen it, that I will have to remake too. the new floor will be higher than the sea when the (20hp) outboard is mounted.

[John ilett]

Don't use the expanding polyurethane faom as it is certain to absorb alot of water with time especially in small wet dinghy. You could do a nice foam sandwich floor with PVC foam but probably easiest is to stick with using ply but give it good 100% coating or two of epoxy resin.

[sigurd]

Are you saying to cover the ply in epoxy with no glass mat? (except for the joints ofcourse I guess)

will epoxy bond well to the rest of the hull which is polyester?

[JR-Shine]

If you use a two part foam it probably wont have the compression strength necessary to stand on. Most two part foams are 2,4, maybe 6 pound densities. As soon as you started walking on it, it would probably compress and the FRP skin would delaminate. The easiest thing to do it replace the floor with plywood coated epoxy and laminated on the top with some cloth for abrasion resistance. Use some 4" FG tape and wood flour fillets to fix it to the sides. This would be very strong and last a long time. You could use foam core, but it would be very expensive and you wouldn’t really gain much for a dingy. That’s my 2 cents. Good luck.

Joel
Boatbuildercentral.com

[sigurd]

thanks