Deck Materials/Design Question...

Hello all,
I recently found this forum, and quickly realized what an amazing resource this place is for the amateur boat builder. Since I’m in the early stages of my own boat modification project, I’m hoping that I could get some design/material pointers before I get too far in the wrong direction.
Compared to many of the projects I’m seeing on here, mine is relatively simply. I’ve got a small fiberglass flats boat that I’m adding two new decks to, one in the bow and one mid-ship.
The bow deck is roughly triangular, 30” wide at the base, extending 54” to the tip. The longest unsupported length would be 41” down the center of the triangle.
The mid deck is trapezoidal. 39” at one end, 32” at the other, and 55” long. The longest unsupported lengths would be 33” in one direction and 37” in the other.
Both decks will have two hatches in them, and they can easily be supported along the entire perimeter of the decks if necessary. There should be at least 12” of uninterrupted deck between hatches and from hatch to nearest support.

Now for my questions…

Could someone help me determine the best materials to use for my application, how thick and how many layers?

Will I need to provide additional support toward the center of the decks, or will supported edges suffice?

I’m thinking some type of epoxy over ply, since this is my first attempt at marine fabrication and those materials seem easy to obtain. It’ll need to support a 250lb. guy, plus gear and hopefully the occasional weighty fish. I’d consider alternate core material, if it’s not too costly or difficult to obtain.

Thanks in advance for any responses!

 

Well, I've checked this forum every day to see if anyone replied, and I must say I'm underwhelmed by the response. I'm amazed that I didn't even get a "welcome to the forum".

Sorry if you feel my project doesn't live up to your standards and warrant a response. I shall not post again...

 

deck material design question

Sorry no one has responded. Some times it takes a while. I know I posted once and it took a week to get a response.

Any way. I think you are on track with plywwod and epoxy. Keep it simple. Marine plywood uses water proof glues so even if you don't do the best job sealing it it is less likely to delamainate. Plus you can use regular tools to work the material. I would think plywood with a thickness of 1/2" may work with out additional support but for a few extra $ you can go to 3/4" and be positive it will support a 250lb person, gear and some fish. Cover with 4 or 6oz. cloth and epoxy and that should give good abrasion protection and water proofing.

 

I built a very similar deck on a plywood johnboat with a similar hatch opening in it. I used regular 2 x 4's the length of the deck along the sides of the hatch for support and a couple of 2 x 2 's about 14" away from them. I used epoxy for the glue and exterior rated 1/2" plywood. It has the same glue as the marine grade wood but it is not as goos since it had voids that can get water in them and rot faster. I did not glass it but should have. I weigh 230 and it barely flexes with me on it. A layer of woven glass on each side would make it much stronger.

JIM

 

You may feel more comfortable with some structural supports installed, to keep this new fore deck from flexing and relatively light weight (the big issue, in small boats).

Attach a piece of one by stock at the back of this fore deck along the edge, so that it will have something to sit on along this edge. Do the same down the centerline.

You can put plywood over this and have stowage underneath or cut some lockers into the top (rod, bait or live wells etc., with hatches for covers.

Another method would be to make a plywood bulkhead at the after end of the fore deck, which also could have access/stowage holes/lockers cut into it.

The midship deck can be a box of plywood or using the same one by stock on the unsupported edges thing, I mentioned first.

This is the down and dirty way to get things done. There are many methods you can employ, some could include: a solid 'glass laminate, a composite laminate, wood core, all wood, plywood sheathed (mentioned), among others.

The key to using wood, as you may have noticed in reading previous posts here is to seal it up, usually with epoxy, so moisture doesn't get at it and cause rot.

After fitting all the pieces (1/2" plywood and 1 x 3's are all you need) and temporarily attaching it with fasteners, remove it and epoxy the crap out of it (three coats) especially the end grain. Reinstall it and tab it in place with cloth tape. It would be wise to skin your efforts with a light 'glass cloth to protect it from dings and nicks, 4 to 8 ounces being fine.

There are many previous threads on the subject of applying and installing wooden pieces to 'glass boats, so use the search tool some more and get a feel for it. Also try the epoxy manufactures (particularly the one you'll be using) web sites, as they also have tips and advise about these types of installations.