Building a boat based Higgins design or the LCVP and suggestions will be appreciated

[H-bomb]

The boat i am building is for a contest for my local lake and the boat has to be hand made out of wood also there is a limited amount of time to make the boat close to a month and a half. so i thought the LCVP design wood be the easiest and most simple to make in a short amount of time the demensions are 8ft long 4ft wide and 2ft high sides with a 30 degree pitch in the front and im using 2 trolling motors that provide 40lbs of thrust each. For materials i am using 1/2 inch plywood sheets and 2x4 for the framing and for sealer i am using a industrial strength waterproofing sylicone spray on paint and then using a enamal oil based paint over that. If anyone has any suggestions they will be greatly appreciated
Thank you

[hansp77]

H-bomb,
Have you already bought the 'industrial strength waterproofing sylicone spray on paint'?

Hopefully somone can answer this (as I have no idea)
Will there be any issues of compatability between this paint and the enamel oil based paint?
Is this paint a recomended one for this application?

I wonder if this is the best (and cheapest) way to go?

the enamel oil paint (IMHO) should be good enough on its own (and if money is a concern- when isn't it?- it should easily be the cheapest option).
It is all my boat has had for its 40+ years living on the water.

After the competition,
how long do you want this boat to last, and what sort of use and storage will the boat have?
Just for more info,
what plywood and timber are you using?

Hans.

[H-bomb]

yes i have the sylicone spray on paint also im storing it in my basement the type of plywood i am usin is hard pine

[PAR]

On a pram with those general dimensions, your planking should be 1/4" not 1/2", though 3/8" on the bottom would provide some security in beaching. The framing of structural components (frames, etc.) don't need anything near the weight of a 2" x 4". In fact, if well thought out the boat can be nearly frameless (taped seams), with just a thwart or two, some chine battens and the two transoms providing all the stiffening necessary. If you elect to build ply over frames, I'd use 1" x 2" on close enough centers to keep the panels from flexing excessively, say about 16".

I wouldn't rely on spray on goo in a can for water proofing, but would use polysulfide with the ply over frame or epoxy on the tape and seam version. There are lots of these little pram/tender plans available (I have a few to offer too). Most now use the tape and seam construction methods, which create a strong, water tight little craft. Ply over frames is a more traditional method, with less goo factor, but more wood working.