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How do I install the bottom marine Plywood. How do I form the curve of the bottom near the bow. Do I muscle the plywood into place from bow to stern?
I plan to CPES the edge to seal, but do I use 5200 in the seam to seal the bottom to the first strake?

I guess yes, just force the plywood to bend. Maybe cover the boards in old towels and pour boiling water over them to help bending?????

I would suggest applying CPES to all the surfaces, not just the edges.

And yes, you need some type of caulk between the planks. 3M5200 is permanent. You or the next owner will have to destroy the wood to get it apart in the future. Flexible marine caulk such as BoatLife might be better.

Andreas

Rong,

I agree with Andreas on using BoatLife sealant rather then 3M 5200, CPES on all surfaces and wetting the plywood to help relieve stress in the plywood when bending it.

Also when applying your plywood start at the bow and work your way toward the stern. This will give you more leverage when bending the tight bend at the bow.

Good Luck,

Phill

thank you for the fast reply. It looks like there should be an easier way but starting from the front and working back makes sense. I will take your advice. this project is years in the works and it must get done now. Next year it must be in the water.

0ne more thing - how do i apply the sealant between the planks if I am prying and bending into place. i believe i would coat both mating edges first then wedge into place. correct?

I am glad you asked these questions I am doing the same thing. Also I i'd like to know what plywood to buy, Fir marine plywood? 3/8? Best way to cut it and scarf it to 16 feet. Best way to bevel edges. Best way to lay bow edge flush. Best way to essentially copy the old garbard and install.

Please be sure to take lots of photos, make scetches, vidio, lengthy step by step discriptions and post them. I have a 59 Seacoaster (posting the restoration on the wooden boat form) and in a few years I will probably look at replacing the hull.

Roger
Aka: Jumper
http://forum.woodenboat.com/showthread. ... y-Thompson

I second that last comment - pics video etc. I plan on enjoying her all next year, but would like to do a plank off restro at some point to include new garboards, new sister keelsons, and likely many new frames (ribs).

You might want to wait until after your plywood is completely in position before using CPES... Even though CPES is still flexible after it cures, it is epoxy.

It seems to me that if you coat it with CPES and wet/steam the plywood and then don't bend it that day, or need to retink your process a few days, you might also be fighting the cured epoxy when you get back to bending the plywood into the right shape.

In addition, it would be better to coat relatively dry wood and let the CPES wick into the pores, vs. having them full of hot water.

I was successful at scarfing the 3/8 marine ply, beveling the edges and bending it into place.
Pictures to follow. I wrapped Bath towels soaked in hot water around the bottom ply at the bow. Then used pipe clamps and ratchet tie down straps to slowly curve the plywood into place. It bent easily and I left the towels there for a couple of days to dry. Once removed the boards stayed in their new shape. It was very easy to do.

Good for you!.
Many of these task seem very difficult until you try them.
Post some pics.
Torchie.

looking forward to the pictures!

The pictures shown in the link (if i did it right) should show the stages of bottom prep.
First I ripped a 4x8 sheet and planed the ends with a power planer. To scarf the 3/8" marine ply I choose (a little more than the 1-12 ratio) a 5" scarf.
Tip - to know if the scarf is even, make sure the layers of ply look like parallel lines across the length of the scarf. (see Photo)
Then used West Systems epoxy plus filler mixed to mayonnaise consistency. I applied the epoxy to both sides, aligned the pieces, lined the outside with plastic and clamped between 2 metal straight edges (5" wide) using pipe clamps.
Note - do not clamp too hard, as you don't want to squeeze all the epoxy out of the scarf.
Once glue set, I sanded the scarf smooth and using the old bottom as a template traced and cut out the pattern.
Again using the power planer I followed the old bottom to create the beveled edge on the new bottom.
The bottom bow ends were wet using hot water soaked bath towels and pipe clamps to slowly bend the plywood into position.
The towels were left to dry then removed to allow the wood to dry in place.
The bottom pieces were then coated with CPES and left to dry until no longer tacky then put back into position on the boat to maintain proper curve.
Once completely dry glue and screw.
http://imageshack.us/g/1/10218476/

I am not sure if this will help for everyone but this is what worked for me.

Rong,

Nice job looks good.

A suggestion for bending the planking on the curve like what you did here is to start at the bow and work your way back toward the stern. In this way you have the long length of the plank to use to help bend the plank to conform to the curve.

Good Luck,

Phill