Mahogany Planking over Plywood Skin

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ctboater
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Mahogany Planking over Plywood Skin

Postby ctboater » Thu Dec 18, 2014 10:12 am

Hey Everyone,

Looking into a few designs and was wondering what everyone's thoughts are on strength of mahogany planks over plywood skin.
I'm looking at the Bravado and it has 3/8" plywood sides. If I were to put 1/8" mahogany over it, could I reduce the plywood skin to 1/4" so the total thickness would equal 3/8",or should the 3/8" plywood still be used with 1/8" planking over it?

I know a few people have planked over the plywood skin, and am interested in what people think.

http://www.boatdesigns.com/17-Bravado-d ... ducts/309/

Mike

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Bill Edmundson
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Re: Mahogany Planking over Plywood Skin

Postby Bill Edmundson » Thu Dec 18, 2014 10:55 am

Mike

That has always been my thought on it.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

Jopip
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Re: Mahogany Planking over Plywood Skin

Postby Jopip » Fri Aug 11, 2017 12:28 pm

Unsuccessful in search for 1/8" mahogany for my barrel back.

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Bill Edmundson
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Re: Mahogany Planking over Plywood Skin

Postby Bill Edmundson » Fri Aug 11, 2017 12:33 pm

I've always cut my own. 3/16", then plane and sand.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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galamb
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Re: Mahogany Planking over Plywood Skin

Postby galamb » Fri Aug 11, 2017 2:34 pm

On my last build I put 1/4" mahogany strips over 1/4" plywood to (make up) my 1/2" sides - over that I put 4oz cloth and clear finished.

On my current build which calls for 1/4" sides (3/8" optional) with 3/8" bottom - all plywood, I plan on using 3mm plywood covered with 1/4" bead/cove Western Red Cedar (canoe strips) - so 9'ish mm total (essentially) 3/8", again covered with 4oz cloth (for the sides - the bottom will get 3/8" plywood).

The look I am going for in this second case is the cedar strip construction that was popular in late 1950's runabouts.

I (believe) that the 3mm plywood "backing" will provide the support for the strips (since they will run between frames instead of closely spaced ribs) until all the epoxy sets up. Then with the 4oz cloth over top should certainly be as strong as/stronger than 1/4" plywood (minimum called for) and possibly even stronger than 3/8" plywood that is not covered with cloth on one side.
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

JimmY
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Re: Mahogany Planking over Plywood Skin

Postby JimmY » Sat Aug 12, 2017 5:47 am

I asked Glen L the same question on for a Squirt with 1/4" sheeting, and the answer I got was that 1/8" plywood would "sag" between the frames. I think with 1/4" sheeting on the size boat you're looking at would be okay. You just need a good bond with the mahogany.

I ended up centering with 1/42" mahogany applied with a vacuum bag.
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!


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