Cockpit Floor Material

A couple of years ago I laminated a plywood cabin top, similar to what you are doing. The dimensions were 10' long x 8' wide. I used 2 sheets of okoume ply 1/2" to form the laminate. The top had a crown so I had to make up formers to support it during the build. Once I placed the bottom sheet and secured it to the perimeter using silicon bronze screws/epoxy I got to work on the lamination. I mixed a fairly large batch of epoxy with slow hardener (actually multiple batches) and thickened the mix to a ketchup consistency. I applied the resin with a mortar spreader such as you would use to spread thin set mortar for tile work. I marked the stop sheet for stapling using a pattern of a staple every 4 inches, used a "sharpie" marker to make the grid so I could keep track of what I was doing. I then laid the top sheet of ply over the bottom and using 1/4" narrow crown staples worked from the inside to the outside. Since I was standing on the top as I went along my body weight helped hold the ply together as I stapled. Just be careful not to staple your tootsies! Some resin squeezed out the edges so I assume I mixed enough to get a pretty good bond. Finished the top with some 4 oz. glass cloth and then painted. It's been finished now for some time and I can't find any problems with it.

For your application you could use 5/8" staples.

MIA

 

Fortunately my cockpit floor is completely flat (versus cambered like my flybridge floor). I am increasing the slope by 1%, as the old floor did not drain well toward the aft scuppers while at rest. This of course creates extra work in modifying the existing floor support structure to accommodate the increased slope. Using Google Sketchup, I've created a 3D model of my cockpit floor including floor supports. This has helped me to realize that by adding one additional floor support, I can minimize the number of floor seams. And all of the seams will be fully supported by the floor supports.

In taking this approach I can get by with three large floor sections built at home. The down-side is these larger sections will be heavy to transport and manipulate into place. The weight is dependent on my final selection of plywood. Regarding Meranti marine plywood, my preferred (Canadian) website lists 4x8x3/4” BS1088 at 60 lbs, BS6566 at 82.5 lbs, and BS6566 13 Ply at 100 lbs. I need to confirm these weights – seems like a really big difference to me. Regardless of the ply that I choose, I am thinking I'll have to build a rough overhead tower that I can use to help me suspend each floor section while I manipulate and glue each section in place. The adventure continues.

 

Since weight is an issue (and your back) you might want to reconsider the 3/4" and look at the 3/8" laminated option that PAR mentioned in a previous post here. Along with my cabin roof I did a laminated foredeck a couple of years ago and it also worked out fine. As Michael said you can measure carefully and cut your parts out in the shop or garage. Coat everything with epoxy (I do three coats), lay bottom sheet in the boat, install the top sheet, secure, fill the seams, sand and lay your fiberglass cloth. If you're off a little bit on the edges, trim to fit or if the sheet is slightly small you can fill the edge with thickened resin. Once you put the cloth down it'll look fine.

You're doing everything right. Sealing and minimizing any standing water (increasing pitch) is the right idea. I understand that you want to do a first rate job. You will. Don't over think it.

Have fun,

MIA