Replacement decking 1/2" or 3/4" marine ply

[Pst76]

I am tossing my options in decking replacment on a 19ft 1984 four Winns I/O cuddy. New stringers are installed and glassed in ready for decking. Original floor was 1/2' plywood probably just exterior grade. <br />Looking at either using 1/2" marine which was original decking thickness or going to 3/4". Both of which will be glassed in. I like the thought of 3/4" floor for the strength. But also thinking if I go 3/4 with the extra thickness using exterior grade instead. Any thoughts on this would be welcome.

 

[Buttanic]

Re: Replacement decking 1/2" or 3/4" marine ply

I would use 3/4 treated exterior, just let it dry for 3 or 4 weeks before glassing over it.<br />You would not gain any advantage using marine ply.

 

[Boomyal]

Re: Replacement decking 1/2" or 3/4" marine ply

If your boat was originally constructed with 1/2" that's what I'd use. I just redid mine with an imported 7 ply 1/2" exterior grade board. By the time I glassed it over, using 10 oz cloth w/ with two coats of epoxy, there is hardly even any flex on the 24" wide gas tank cover. (no center support)<br /><br />What ever you use. be sure to seal it good. I gave mine two coats of CPES then rolled a coat of epoxy on top of that.<br /><br />

 

[Pst76]

Re: Replacement decking 1/2" or 3/4" marine ply

I have a frame that I build that will support the area over the tank. I built it as that if I had a problem with the tank I would be able to cut through glass and plywood and remove only that area of the floor. Also built a frame around where access hatch to tank connections will be. <br /><br />I have 6oz cloth and was going to double up layers along outer seam in strip fashion and then top layer the whole deck. Material would will be sealed and coated prior to install.

 

[Lou C]

Re: Replacement decking 1/2" or 3/4" marine ply

You can e-mail 4 Winns to ask them what they recommend. I did this when I replaced a section of floor in my 1988 200 Horizon. <br />Like Boomyal said seal it up well. I also used CPES and the layup and laminating epoxy resin sold by rotdoc. Really good stuff and made a strong repair. BUT, the CPES has tons of solvents in it, so wear a fume respirator! and good chem resistant gloves for the epoxy since some people develop a strong allergic reaction to it.

 

[Pst76]

Re: Replacement decking 1/2" or 3/4" marine ply

Thanks Lou, I had contacted Four Winns before I started the project. Great company. They sent me every peice of doucumentation available for the boat right down to the original blueprints. I got all dimmensions for stringers, bulkheads,decking the works. Even have spec for uphostery of the seats and cabin area.They were great to work with.

 

[Pst76]

Re: Replacement decking 1/2" or 3/4" marine ply

In answer to your suggestion they felt that the 1/2" would be suffient exterior or Marine. Forgot to add in last post.Thats probably the dirrection I will go. However I am using Poly Resin as opposed to epoxy. Stringers are polyed in as well.

 

[BillP]

Re: Replacement decking 1/2" or 3/4" marine ply

Weight difference between 1/2" and 3/4" ply is appox 25lbs a sheet. I used 3/4" pt in a 17' ob for the floor and couldn't tell the difference in performance. Top speed is still the same too.