fiberglassing douglas fir marine ply on garvey project?

[luke k]

this is my first post but im 16 and im building a garvey for clamming. im using fir marine ply and i know that most of the builders near me just fiberglass the out side of the hull and paint the inside, well i dont know what ply they use, but im using douglas fir and cypress ribs and chine logs.i have know experience with douglas fir and was wondering should i glass the bottom of the inside of the boat or if its not needed. i dont want the boat to rot out on me after a year or 2 and ive heard that fiberglassing helps and ive also heard that its not needed and the wood should be able to breathe? please if any one can help me with this? its a 14 foot garvey with a max beam of 5 feet. thanks

 

[Woodonglass]

Re: fiberglassing douglas fir marine ply on garvey project?

Welcome to iBoats!
At the very least you should fillet all seams with thickened resin and then use fiberglass tape to seal them. I assume you are using Epoxy resin. I hope so. I would use a 7.5 oz biaxial cloth tape for the seams. I would then recommend coating the entire interior of the boat with a coat of epoxy. The wood does not need to breath. It needs to be sealed from moisture. A couple of coats of Oil Based Paint (Rustoleum is a good choice) to finish her off and she'll last for several years. Rustoleum is easy to find and easy to touch up.
Post some Pics so we can see what you're building.

 

[luke k]

Re: fiberglassing douglas fir marine ply on garvey project?

i havent done any glass work yet but all the seams were done with loads of resin and s.s screws, i planed on glassing the seams, so u think a coat or 2 of epoxy will hold up fine on the interior? ive heard other guys take about the plywood checking but if anything i guess i could just fix it up eventually were it does and then re paint it? im concerned about any water that might sit to long on in the bottom of the boat. ill post some pctures soon but im going by a russ adams design thats been changed up a bit, you can find his boat if you google him, thanks for the help

 

[Woodonglass]

Re: fiberglassing douglas fir marine ply on garvey project?

There's all kinds of epoxy. There's a formula for High Flex Epoxy (West Systems calls theirs G-Flex) that would work well for your interior hull and the plywood should not "Check" on you. All the researching I have done on wood boat building indicates that all of the hull seams should be "Taped" both Inside and Out. Not saying you HAVE to, just saying what is recommended. I did google it and found pics. Nice little boat. If there's a possibility of any rough water I'd tape the outside seams just to be safe. What thickness of ply are you using?

 

[luke k]

Re: fiberglassing douglas fir marine ply on garvey project?

im using half inch on it and the whole exteriors gonna be glassed, i was planing on just glassing the seams on the inside. and ill most likely use the epoxy on the rest of the interior then paint over it, it should come out nice, ive just been confused on the whole debate about if i should or shouldent seal the plywood interior. i plan on putting a yamaha 20 on it will a tiller it should run good with a 20 they dont take much to plane.