New Deck Support Question

[John F.]

I need to make new aft deck supports. I'm planning on using mahogany for the verticals--that's what I think the old vertical supports were made of. For the horizontal supports that run fore/aft from the rear engine bulkhead to the transom, I was planning on using two layers 3/4" marine ply ripped to 3" or 4" widths and glassed together--so the support would be 3" or 4" x 1 1/2" by whatever length. I do have a 4x8 x 1" thick sheet of some type of PVC board. Should I use that for the horizontals instead? Maybe rip that to 4" widths and epoxy two together to make a 2"x4" plank? Any advice?

[Pete Fallon]

John,
I am doing the same thing, replacing deck supports, my 1961 express has original mahogany, 1'' x 7'' boards, they tapper from 7 1/2" forward to 5-1/2" aft and are 98" long on all 4 pieces that thru-bolt to the stringers. The section under the teak transom trim was 3/4" marine plywood tabbed to the transom with FRP, that section is 7'' wide by 106" across the interior transom. The teak trim board is screwed from the under side of the plywood into the teak with #8 1-1/4" bronze fasteners.
I looked into using Coosa board, but you still has to seal the edges to keep the water out, mahogany was less money, I figured if the old stuff lasted 48 years and I won't be around that long. I am coating the wood with 3 coats of E-expoxy (thinned expoxy). Make sure your rudder tables and steering linkage supports are still good, it's easier to do everything at the same time. Good luck with your project.

[Rawleigh]

I still like the idea of using the structural epoxy members from Mcmaster Carr instead of wood.

[Carl]

I played with the idea of using wood again myself when redoing the deck.

But as Rawleigh said, Structural Fiberglass supports are the way I went. Price was inexpensive from McMAster, delivered to my door the next day, easy to cut, bolted them together then glassed together after I checked the fit of deck. True the originals lasted years, but know I don't have to worry about sealing the deck seams, screws etc.

[John F.]

OK--if I go with the fb glass stuff from McMaster, what should I get? I've never worked with this stuff. Thanks. The appeal of the PVC board is no rot, and I have it sitting im my garage (free).

[CMP]

Pultruded fiberglass i-beams and Plexus glue are the way to go. Fast, stronger and lighter than traditional methods-without a doubt a better solution. Worked great for me on both Berts I did. Here's a link to teh company from which I buy...

http://www.frpcomposites.com/

CMP

[Carl]

http://www.mcmaster.com/#plastics/=oqpe4

I used the the 1 x 3" fiberglass U channel as per link. Fastened the solid back to the stringers and bolted the channels back to back.

Dave Kosh used box tubing in the same material, although I don't think he liked the hollow tubing for joining together.

Free is great, but not sure how much structural strenght you will get from PVC.