Cracks in my wooden boat - good pics

[gvegas88]

A friend of mine built this 14ft jon boat from marine plywood and epoxy. He is out of the country so I can't consult him on this issue. Well on my last outing I managed to run up on a small, but rigid stump. The epoxy on the hull is so flexible that no damage seems to have been done to it, but the wood and paint have cracked. I really don't want water to get into the wood, so I'm hoping to fix this problem the right way. Also, would it make sense to add some 2x4 supports on the deck that are perpendicular to the boat and the ribs on the bottom of the hull because the boat flexes alot left to right but it doesn't flex much front to rear obviously. I'm thinking that he would have to add the supports because they would need to be epoxied to the floor I guess.

This picture is a close up of part of the most severe part of the crack. The total length runs about 16in

Pic of the boat and the word "crack" is over and parallel to the actual crack

This is a picture of the bottom of the boat. you can see the ribs and the epoxy + epoxy w/ graphite hull coating

Thanks, Tyler

 

[i386]

Re: Cracks in my wooden boat - good pics

Forgive me if I'm jumping the gun here. I don't see any fiberglass there in the thin layer atop the plywood. A layer of epoxy over wood will add little if any strength.

 

[gvegas88]

Re: Cracks in my wooden boat - good pics

Yeah there isn't any fiberglass on the boat. I am mostly concerned with sealing the cracks and potentially adding a rigid floor support like a 2x4 or something of that nature. Thanks, Tyler

 

[ghamby]

Re: Cracks in my wooden boat - good pics

Grind out that crack in a V shaped groove until you have adhered epoxy showing on the plywood on the inside. pour in some clear marine epoxy.
Layer in some glass cloth,starting witha narrow strip and increasing the width as you stack it up. Saturate the cloth with clear marine epoxy as you go.
A 1 pint kit ought to do it along with about 6' of 2"fiber glass cloth. Get the stuff on a roll that looks like tape. If you shave down the repair with a Shurform when the epoxy is at a tacky stage you will save a lot of sanding.
The blade will want to clog up, so have a pan of lacquer thinner or brush
cleaner handy. Wear some good gloves. Scrape the Shurform ridges out
with a utility knife blade. When cured sand smooth.
As to bracing, 2x4 is for framing houses.It's too damn heavy and will use up
it's strength trying to hold itself together. I would go with some 5/4 x 2 white
oak for the cross members and perhaps the same for the frames from chine
to gunnel.
The crack repair is one thing. Adding framing to this guys boat is another.
It's quite involved and will alter the boat quite a bit. If you don't know from
from wooden boat building,find yourself a proper boat carpenter.
Good luck, GH