Marine Plywood for Deck

[minaret]

Originally Posted by kazenza

Thanks everyone for the great feedback. One more question is I've seen several references to the Gougeon Brothers method for adhering a teak deck w/o fasteners, but can't find a summary of it anywhere. Book seems to be out of print, and don't know that I want to buy another boat book (have quite the library now). Anyone with information on this, I would love to know more of the details.

Personally I don't think the Gougeon Bro's system is all that great as it uses screws and washers for clamping. But that is because as a pro I have access to hundreds of specialized clamps made just for the purpose of laying teak decking without sticking a bunch of screw holes in the substrate. For the DIY job Gougeon makes good sense. Here is a link to an example of the method, and another for an example of more traditional laid decking instead of sprung.

http://www.epoxyworks.com/20/pdf/Ew20_Teak_deck.pdf

Building Peterson's "Susan" #8

[Lojanica]

Minaret. If I may float a question. I am refitting fuel/water tanks in my boat which necessitates rebuilding the cabin sole and floor bulkheads. Which material would you use? I was going to use plywood. Which type do you recommend? Over the top of the plywood I was considering IPE. Again any thoughts? I am interested in a good job at a decent price.

Regards.

[minaret]

Originally Posted by Lojanica

Minaret. If I may float a question. I am refitting fuel/water tanks in my boat which necessitates rebuilding the cabin sole and floor bulkheads. Which material would you use? I was going to use plywood. Which type do you recommend? Over the top of the plywood I was considering IPE. Again any thoughts? I am interested in a good job at a decent price.

Regards.

Floor bulkheads are properly called simply floors. For them I would use in most cases a 5 lb. Airex foam core, which is very easy to shape and bond together in any desired thickness, laminated heavily. The layup and tab can happen all in one go, it's stronger that way. In other words the encapsulating laminate can tab onto the hull. Then I use 1" fiberglass tube glassed in with a couple of matts for the limber holes. After glassing hit the whole thing with a grinder real quick to clean up any imperfections and brush a couple of coats of gelcoat on. It looks factory, can never rot, and is very strong.
As far as the sole you put on top of the floors goes, there are numerous products which will fit the bill nicely. Which one you use will probably depend on which is most easily available to you and match's your existing sole. One disadvantage to a foam/fiberglass floor arrangement is that you can't use screws to fasten your sole to the floors. But that's half the point, no penetrations into the core. It's actually very easy to use adhesives instead, and in places where you really want to screw or even bolt you can put in some ply or even steel or alum before glassing and screw or drill and tap into it. I really like modern methacrylates for bonding in situations like these. It takes practice because open times can be as little as ten seconds depending on which product you use but methacrylate bonds have to be destructively tested to be believed. I prefer Plexus. The layman's option would be WEST epoxy.


Plexus - Structural Adhesives

[Lojanica]

Originally Posted by minaret

Floor bulkheads are properly called simply floors. For them I would use in most cases a 5 lb. Airex foam core, which is very easy to shape and bond together in any desired thickness, laminated heavily. The layup and tab can happen all in one go, it's stronger that way. In other words the encapsulating laminate can tab onto the hull. Then I use 1" fiberglass tube glassed in with a couple of matts for the limber holes. After glassing hit the whole thing with a grinder real quick to clean up any imperfections and brush a couple of coats of gelcoat on. It looks factory, can never rot, and is very strong.
As far as the sole you put on top of the floors goes, there are numerous products which will fit the bill nicely. Which one you use will probably depend on which is most easily available to you and match's your existing sole. One disadvantage to a foam/fiberglass floor arrangement is that you can't use screws to fasten your sole to the floors. But that's half the point, no penetrations into the core. It's actually very easy to use adhesives instead, and in places where you really want to screw or even bolt you can put in some ply or even steel or alum before glassing and screw or drill and tap into it. I really like modern methacrylates for bonding in situations like these. It takes practice because open times can be as little as ten seconds depending on which product you use but methacrylate bonds have to be destructively tested to be believed. I prefer Plexus. The layman's option would be WEST epoxy.


Plexus - Structural Adhesives

Thank you. I am unlikely to be able to do what you described however of the following if you had to use plywood for a repair which would you choose? Should it be sealed with epoxy prior to installation?Douglas Fir marine plywood Meranti "Hydro-tek" marine plywood Meranti "Aqua-tek" marine plywood Okoume "Joubert" marine plywood

[minaret]

Originally Posted by Lojanica

Thank you. I am unlikely to be able to do what you described however of the following if you had to use plywood for a repair which would you choose? Should it be sealed with epoxy prior to installation?Douglas Fir marine plywood Meranti "Hydro-tek" marine plywood Meranti "Aqua-tek" marine plywood Okoume "Joubert" marine plywood

I'd go with the doug fir. But for building floors I would generally speaking also totally encapsulate ply floors as well, which means that it's actually materially cheaper and faster to use a foam core. The only real difference is that the foam core is much faster and easier to fit, but will require a heavier laminate schedule. Plus you won't be doing this again in ten or twenty years because the ply rotted. I have seen plenty of un-encapsulated ply floors, but mostly while I was cutting them out because they were rotten. I've also cut out miles of rotten encapsulated ply floors and stringers, usually due to poor forethought in the limber hole department. If you do build ply floors be very careful how you limber them. Sealing with epoxy is the very least I would consider, but then you need to tab them in with an epoxy laminate as well.
Incidentally ,what sort of boat are we talking about here? Hard to give good info when you don't know. I would probably suggest different solutions for a $2000 24' boat than for a $200,000 40' boat.

[DSDman]

This is a great thread. among my many projects replacing the sole is one. I was going to wait and do it but since I will also be replacing some of the furniture and other woodwork I'm thinking of moving this chore up the list. also gives me a chance to really inspect and replum the tanks. I had not even considered going with the foam core panels. where can I buy those? I like the idea of gluing the wood floor, or imitation vinyl right to it. my boat is 60 ft so it s going to take a bit. mineret if I were going to pay someone to do this what do you think it would cost?

[goboatingnow]

Originally Posted by Lojanica

Thank you. I am unlikely to be able to do what you described however of the following if you had to use plywood for a repair which would you choose? Should it be sealed with epoxy prior to installation?Douglas Fir marine plywood Meranti "Hydro-tek" marine plywood Meranti "Aqua-tek" marine plywood Okoume "Joubert" marine plywood

Why are you unlikely to be able to do what minaret says ( which is spot on) . I would avoid plywood for floors especially in areas subject to standing bilge water.

Dave

[minaret]

Originally Posted by DSDman

This is a great thread. among my many projects replacing the sole is one. I was going to wait and do it but since I will also be replacing some of the furniture and other woodwork I'm thinking of moving this chore up the list. also gives me a chance to really inspect and replum the tanks. I had not even considered going with the foam core panels. where can I buy those? I like the idea of gluing the wood floor, or imitation vinyl right to it. my boat is 60 ft so it s going to take a bit. mineret if I were going to pay someone to do this what do you think it would cost?

I think there may be some minor confusion here. I was suggesting a foam core for structural floors rather than cabin soles. There are however all sorts of premade sheet materials for cabin soles, including some with foam or balsa cores. These tend to be very expensive. There are ways to produce similar panels at home but either way is extremely time consuming and expensive. Most good methods involve vacuum bagging as among other things a way to minimize "potato chipping" and insure a flat panel. That is a different and more complicated discussion though. For most people sticking with a premade ply paneling with teak and holly laminated to it (for example) and carefully fitting and trimming it in a more traditional manner will be by far the most efficient method to achieve a new sole. Only those who are really concerned with weight savings usually look at composite sole panels.

[minaret]

Originally Posted by goboatingnow

Why are you unlikely to be able to do what minaret says ( which is spot on) . I would avoid plywood for floors especially in areas subject to standing bilge water.

Dave

So many people feel comfortable working with wood and have no experience with fiberglass laminates and are thus a bit afraid to try. I see it a lot. The method I am suggesting here can be done by any intelligent person with a little research and study. I have trained a lot of young guys in the yard who in some cases didn't have good english (ie none) or weren't the sharpest tool in the shed (the bosses nephew). It's really not rocket science at this level. The internet is rife with info including the ubiquitous YouTube videos to show you how.

[Lojanica]

I am cutting out only part of the floor. The rest will remain as the existing 3/4" marine grade mahogany faced "Meranti" ply. The reason for this is that the refit would be much larger were I to remove the entire sole. The "subfloor" will remain mostly intact. I like the idea of composite or coosa or plastiboard, or FRP foam core but the problem there will be tying it into the existing strcture because as you say it will have to be bolted not screwed or nailed and that may represent a challeng. So I suppose I will go with the Doug fir cca treated marine ply, epoxy sealed, followed by a bilge paint coating both sides. Then maybe a solid teak raised removable floor in a shower grate style.

If I was removing everything and starting over I like your method better but such is not the case.

[Lojanica]

Originally Posted by minaret

Yes, that is one of it's strong suits. It sticks amazingly well with zero prep. It's a high density foam with fiberglass laminate in it, so the surface is kinda porous. Perfect for laminating to and takes coatings very well. I have used it for over a decade now in all sorts of marine applications, it's great stuff. Lighter than ply but stronger and guaranteed to never rot. Comes in several densities and amounts of laminate for different applications. Much cheaper than regular cored composite panels, but obviously not as light as a high end composite panel. For a deck ply replacement I would use Coosa and laminate a couple of plies over the top to provide durability and a proper seal all around, making sure to tie in to existing laminate everywhere. About a thousand times better than a ply deck for the same money. I would probably use the Bluewater 26 for a deck, but the 20 would be fine.

So after much hemming and hawing I am indeed following this sage advice and rebuilding with Coosa and glass and foregoing the plywood. Tabbing into the laminate of the hull.

Now one more question. Vinylester or epoxy? And I read by an amatuer that he had adhesion problems from the COOSA mold release? Do I need to wipe with acetone or some solvent prior to glassing?

Thanks for the tips Minaret.

[minaret]

Originally Posted by Lojanica

So after much hemming and hawing I am indeed following this sage advice and rebuilding with Coosa and glass and foregoing the plywood. Tabbing into the laminate of the hull.

Now one more question. Vinylester or epoxy? And I read by an amatuer that he had adhesion problems from the COOSA mold release? Do I need to wipe with acetone or some solvent prior to glassing?

Thanks for the tips Minaret.

Smart man. I've never had a problem with mold release on coosa, but I do always wipe with plenty of 'tone on general principle. Coosa builds knowing your going to glass to it, I can't see them using a liquid wax for release. I would use vinylester or even isotropic poly resin (not orthotropic), either is perfectly appropriate for this job. Using a poly resin will make the whole job much quicker and easier, the only drawback is the high level of stink. If you have zero laminating experience the long open times of an epoxy layup can be a lifesaver, but if your project is of any size you will save a ton of money using poly. Don't forget you can't fasten to coosa, throw in a strip of ply or even the metal of your choice along the top edge before glassing and then encapsulate it with the rest. When your done glassing hit it with a grinder real quick and then brush on a couple of coats of gel, it'll look factory. You don't need to worry about tubes for limber holes with coosa, just limber it up before brushing gel and make sure to gel the inside of the limbers, makes them easier to keep clear and clean. Good luck and feel free to ask for any help you need!

[Saltyhog]

Minaret, Is Baltek Airex PXc the same as Coosa? See PXc . I have some of this and I'm doing some similar projects. Just want to be sure I'm not using the wrong stuff. Thanks!

[minaret]

Originally Posted by Saltyhog

Minaret, Is Baltek Airex PXc the same as Coosa? See PXc . I have some of this and I'm doing some similar projects. Just want to be sure I'm not using the wrong stuff. Thanks!

It's almost the same, but it costs more and doesn't come in a variety of densities like coosa. Should work out fine for most uses, I would compare the numbers before using it for anything really structural like bulkheads.

[Lojanica]

Whoa!!! Yeah priced out the cost of poly vs. epoxy vs. vinylester and yes tons of money will be saved by going with poly......

Thanks again