Plywood flooring

[Tex51]

I am putting a new floor in my boat and it is a small 16ft sidewinder look a like. I was going to go to home depot and just buy 5/8" treated plywood and paint the bottom side with a good oil base paint and the top side would be glassed in with new carpet. Will this work or should I go buy marine plywood for this? Thanks tex51

 

[minuteman62-64]

I wouldn't think you'd need marine ply for flooring. Maybe a BCX? Not familiar with that boat, but if it's aluminum, stay away from the treated ply.

Can you actually bond poly resin (or epoxy) to treated ply? The stuff I've seen in Home Depot is pretty nasty and wet looking.

 

[Rickmerrill]

Agree with minuteman. If it's not aluminum you could use PT but you'd have to dry it out for weeks and keep it from warping to get anything to stick to it. Most here use an exterior grade ply. Anything from BCX to marine will do with Arauco ply and MDO as popular choices. You would waterproof it with poly resin and CSM, 1 layer on the bottom, 2 on the top. See Woodonglass' write up on Decks, Stringers and Transoms http://forums.iboats.com/forum/boat...r-flamingo-splashed-w-pics/page42#post5550980 for more info.

Of course, all this assumes you know your stringers, bulkheads and transom are good. If you have soft spots in your deck they may not be.

 

[kcassells]

Like they said use exterior grade bc...treated stuff is never dry when you buy it from a big box store. Adhesion is 0. There are also alot of price--e-r woods available. Like marine grade or aruco.... BC is perfectly fine if you seal it properly. last 20 yrs.

 

[Bob_VT]

Okay my side winder is in the turtle position since it will sit till next year. If I remember right the entire piece of decking is only what 30-40"wide and nice single straight cut. How is your single keel stringer? The plywood I used was exterior grade since the resin sticking to PT is iffy at best.

My deck was fastened to the center stringer and I used csm and resin to glue it down on the two edges and then a layer of glass over the edges.

Since you are inside there be certain to check the position of the drain holes for the hull into the bilge. One of the problems I discovered was that the srains are drill almost an inch above the hull bottom and would prevent complete draining. Fix that before you re-deck! I did.

Here is mine http://forums.iboats.com/forum/boat...and-hull-repair/594601-sidewinder-cobra-16-ss and sorry I did not take pictures of my new drain holes but you will see the direction I went.

 

[btravlin2]

Oil-based paint on the underside?! Myself, I would glass both sides, with the first coat of resin being thinned for maximum penetration, especially on the edges.

 

[Woodonglass]

It's a proven fact that thinning the resin actually does more harm than good. Poly resin has a low enough viscosity so just precoat the wood first and put down one layer of 1.5oz CSM and you'll be good to go. There are other alternatives if you don't want to glass it, but resin coating and glassing is the best. If you're interested in sealing the wood and painting it though post back and we can discuss that method too!!!

 

[bonz_d]

Read this and then do as I did and research some more!

http://forums.iboats.com/forum/boat...ding-and-hull-repair/8390186-plywood-question
http://forums.iboats.com/forum/boat...pair/8596473-plywood-question-further-insight

 

[Woodonglass]

AMEN!!!^^^^^:tape2:

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[Tex51]

Thanks everyone, my boat is fiberglass and the flooring is only about 30" wide. Bob_VT you are right on the sump pump area. My boat has no drains into the sump pump area and no way to drain water from under the floor once water gets under there. I removed the floor to find the bow area of the floor open to the under Neath. I am going to seal the floor at the bow to the bottom of the boat so no water from the bow area can get under the floor. I have cut the front of the sump pump area open so the sump will drain the water from under the floor. I had no spray in foam under my floor only some foam bats that looked like 2x4's laying under the floor (2 of them 4ft long) and they were water logged and I have removed all of that. I was not going to put any spray or foam back since there since was none to start with, so is there any reason to put it in the boat? The transom and the stringer are hard and show no sign of rot. The stringer in the floor of the boat is only about 6ft long and the boat is 16ft long. I will glass the new floor to the stringer and screw it too. Does this sound like a fix, or should I work at it from a different angle. I am going to the forums suggested. Any ideas are great. This is my first attempt to floor or repair a boat. PS the electrical is missing from the boat too. My education is getting a career change.

 

[rickryder]

Pictures would be great to see what your working with.

 

[bonz_d]

Tex51. Best of luck with your project, you are in control and there are many here that can and will help with any roadblocks you may incounter. If you read those 2 links I'd posted you should see that my opinion is that there is no sure fire perfect solution to repairing/replacing the plywood that is used in decking. There are perfered ways, good ways and poor ways. But none are fool proof.

Some come here to find help with repairs and are on a limited budget, which some members seem to have a problem with. Even with a limited budget it doesn't mean repairs cannot be effected and the finished repair be functional and last many years. Then there are those like me that just don't want to follow the crowd because they all insist that that is the only way it should be done to be done correctly.

I myself am not one to freely spend others money and yes rebuilding/rehabing a boat involves many decisions on how we spend OUR money and resources. Much of which comes down to what is the finished product that you are trying to achieve. Are you repairing to be functional or are you doing a full restore to original. Are you building something you can use or are you building a Monument?

In my case I boat to fish so I lean more to the functional side. If I was to boat for pleasure then I would be leaning more to an old classic and would lean more to the Monument. I have watched many projects come thru this forum, some are painstakenly beautiful, others just very functional and useable. Neither is better or worse they are just someones persective on how to complete their project.

Just remember that the member knowledge base if this forum is tremendous which is what makes this forum so great.

 

[Bob_VT]

The flotation foam in my boat is under the gunwales and quite a bit of it and some under the bow. I did not have any below the decking. My keel stringer was solid and ran just about as far as it could towards the bow (longer then 6').

I used epoxy resin on mine and I coated the decking with epoxy resin on both sides. If you use exterior plywood and put a few coats of oil based paint on it......yeah it will work but just not last as long. I have a friend that used oil based paint on exterior plywood last year....... this year the wood had shrunk a bit and you could see cracks in the top layer.

You can do anything you like to the deck - it is dealer's choice. Just consider the environment, abuse and conditions that the decking will see........ water above, condensation below (and water), weight above and pounding below. Be very certain to attach that decking secure to the hull because it provides allot of strength to the hull.

In reference to your PS. I replaced all the wires in a few boats and I buy "Pre-tinned" wire (aka marine wire) from interstate battery in my local town. wiring is not bad as long as you keep track and label everything.

 

[bonz_d]

I'm kind of familiar with the type of boat you are working with, there were 2 local builders that were building that class of boat. One was Switzer and the other was Hustler. Lots of go fast hulls. They also did not leave a lot of room for flotation foam but then back then that was the norm. I think you should try to get as much foam as you can inside that thing. Many things have changed since then including laws from the EPA and state DNRs as far as who and how much one is responsable if there is a sinking. Kind of a CYA approach in this case.

Agreed that when glass boats are built some concideration is taken as to the strength added by the decking and why it is joined to the hull. I also see a differance between glass boats and aluminum boats. On most glass boats the bottom, stringers, transom, decking are all sealed off. many have little or no bilge area for water to escape to so when it gets under the deck it gets trapped. Has no air movement under the deck and therefore has a hard time removing moisture and drying out. Also many times the pour in foam is completely filled in the whole space and has contact with the deck boards.

With aluminum boats the decking is not joined to the sides which as small as it is still provides a space for moisture to evaporate out. But at the same time because it is not sealed into the sides it provides an area for water to enter into the ends of the ply. Also with the Lunds and Alumacrafts that I have had experiance with the pour in foam does not fill the whole area under the deck and there is usually a large open bilge in the stern.

I also agree that conditions and use should factor into how a plywood deck should be treated. In my case the boat is not left outside uncovered exposed. It is also not left to sit full of water, leaves, wet towles or tarps.

For example, a number of years ago I bought a Lund S14 that has a factory installed flat deck. When I bought it it had been left outside uncovered, exposed. It even had small trees growing inside it. There was also a spot about 15" around that was soft but not a break thru.. 2 years past before I got around to repairing it and after storing it the way it should be when I pulled up the plywood it was all dry though deteriorated from previous exposure. So my experience with aluminum boats is even though they will get wet they also will dry out if treated properly.

 

[Tex51]

No Title

Here are photos of the boat with the flooring removed. There is only about 4" of depth at the 2x4 area in the center of the boat.

 

[Bob_VT]

Do not foam under that deck. foam under the gunwales............ plenty of room and probably have foam in there now. DO NOT foam in the drivers side because controls and wires go there

Hows the transom?

 

[bonz_d]

Pretty much as I expected to see, not much you can do there. Up side is that it looks like it should be a pretty quick and easy repair.

 

[Tex51]

The plywood type was throwing me a curve and I will get CDX from Homedepot and cut it up and glass it to the sides and the stringer and also put screws thru the flooring into the stringer. I am going to build 2x4 frame work and glass that to the floor to mount the seats so I do not screw into the new floor and take a chance of screwing straight thru the bottom of my boat as the previous owner did. Thank y'all for your help. When I get another thousand handy to put into the boat I will post up date of my progress.

 

[Tex51]

Gel coat is not good. I have started on the gel coat by sanding and trying to smooth out the rough spots. I have a 220 grit sand paper on my sander and this gel coat is pretty thin. This is my plan. I am going to sand down one side of my boat and then remove the wooden runner and let the boat set on the rollers. Then go to the other side and let the wooden runner down about 4 inches so this should tilt the boat so I can get all the way to the rollers with the sander to clean the bottom. Then I can paint or regel coat the bottom with out taking the boat off the trailer. Then do the same for the other side. How does this sound? Who has tried this and did it work? There is no way for me to flip the boat by myself unless my wife will pull the motor and flip the back end of the boat while I try to hold and flip the front. I do not see this happening. She claims at 58 years old and 4'9" tall and 129 lbs she is not able to pick up a 115 mercury and the back end of my boat and flip it for me. I guess I am on my on. So is paint easier than gel coat or will gel coat be my best way. I am going to paint it on no matter which way I go. I can sand and polish. What is a good paint or gel coat. My boat is gray but the color my change and that is not a problem. This boat is a 1978 and I probly can not match the color.

 

[fhhuber]

Gelcoat is easier in the mold... spray mold with relase agent... then spray gel coat, then lay up the boat on top of the color.

Applying Gel coat outside the mold is a pain in the neck. Lots of work to get it to look good.

Its better to fill as needed, sand it to get it rough (not glassy smooth, even 400 grit is rough enough) then apply a good quality paint. Paints do some "self leveling" of the surface and will look good with very little work after application.

I'd consider box style seat mounts and putting foam in there if not needed to hide the battery and gas tank. Empty hull you have a lot of options for the interior.

Be careful to brace the hull straight while you install the floor and any structure that could lock in a warp. (another recent poster put in his structure with the hull twisted.)