Replacing a Wooden Floor in a Boat

Weather the plywood in a sunny spot for a couple of weeks minimum first to get it as dry as possible before coating with polyurethane. Give it a light sanding, wipe with a tack cloth, then apply a couple of thin coats. Polyester resins will stick to damn near anything (however, not so good on untreated polyethylene). You won't have a problem with adhesion to the polyurethane coating.

As for Rhino lining, unless you need the abrasion resistance, that would not be my first choice due to its weight more than anything else. Also from an aesthetics point of view the stuff isn't pretty, but then again if this is a lobsta boat or something, you probably don't care about the weight or the looks.

****Brainstorming**** How about this. Using NO plywood. Use the insulation as a base and go between the runners and lay fiberglass between the runners (long ways). Fill up runners by laying mat or cloth and build up to 1/2" thickness. After it dries (layer per layer) becomes a solid fiberglass floor eliminating any chance of rot (no wood). Attaching it to the runners would make it very solid and you can do runner at a time. If you have to replace a runner - Lowes has a PVC board 1" thickness (various sizes and lengths) - has a lifetime warrant and will adhere to fiberglass. This can also be used in the transom which is next. Finish product will be smooth because you can sand - then paint or overlay carpet. Might be a little more expensive but end result would be a fiberglass floor. Now what do you think about that??????

Can you say ouch, glass splinters on bare feet really, really hurt, whereas wood splinters just hurt the once.

If you use the cloth after putting down mat - you will not have glass splinters. Smooth as silk. Can't run glass up under your toe nail - but wood splinter is a killer@*&*^%@!!!!

Yep,. If the material is covered on both sides and completely sealed where no water or other oxidizing chemicals such as salt can migrate into the wood or metal it will hold up for a good while.

However; If there is any small unprotected area that allows moisture, salt, or other oxidizers to penetrate the wood the wood or metal will degrade rapidly due to being sandwiched inside the layers of Rhino Lining.

I have observed treated wood and metal completely rot out within a period of 3-4 months form the date of coating due to unsealed small penetrations such as screws, nails, and bolts and from abrasive contact points.

Preparation and detailed execution is vital to the longevity of the coating.

Just a thought but what about using the composite plastic based decking products?

***Brainstorming *** How about this. Using NO PLYWOOD. Use the insulation as a base and go between the runners and lay fiberglass (long ways). Fill runners by laying mat and build up 1/2" thickness. After it dries (layer per layer) becomes a solid fiberglass floor eliminating any chance of rot (no wood). Attaching it to the runners would make it very solid and you can do runner at a time. If a runner is bad (which mine aren't) - Lowes has a PVC board 1" thick (varies sizes and lengths) has a lifetime warranty and will adhere to fiberglass. Finish product will be smooth because you can sand - then paint or overlay carpet. Overall result - a solid fiberglass floor which is which is my goal. Might be a little bit more expensive but ... Any Comment???

BOAT Break Out Another Thousand

Don't coat the wood with PU and then glass over it.

The polyester or epoxy resin (not fiberglass) will adhere better to the bare wood.

Don't know about Rhino but 10/years in a boat would be good I'd say.

Off the phone now.

Don't coat the wood with PU and then glass over it.

The wood's pores will be sealed by the urethane and not absorb any of the resin used to wet the glass cloth later. So, you have an unnecessary barrier coat between the wood and fiberglass/polyester composite matrix.(To get technical)

One or the other, not both. Sealing the wood, well, with anything is what's needed.

I'd vote for Rhino over the fiberglass layer.

Lyn ****Brainstorming> Why can I not use my foam and a base and fiberglass over it from runner to runner longways. By doing this I will have eliminated plywood completely and any chance of rot. Fglass will be about 1/2 thick which will make a solid floor and water tight. By doing this I can also sand paint or lay carpet over it. My overall goal was to have a fiberglass layer on the top anyway. I know that cost maybe a factor. If I have a bad runner (which I don't) I could go to Lowes and get their PVC board which comes in 1 X 10 x 14. Various lengths and sizes. By doing this I could doone section at a time. Biggest question would be to use either matting or cloth. Which would you recommend?

Oh!

PU foam? That's entirely different. No problem there with adhesion.

For a lay-up that thick, it's definitely matt to make up the bulk of the thickness, then cloth on top for a smooth finish.

You might consider a non-skid finish by laying a very thin layer of sand on the last coat of resin before it dries, but then you'd be walking on wet sand paper. Carpet is the way to go, for sure.

Both my former boats were carpeted and that was nice.

Off to bet on the Belmont, back later.

Good luck.

Glad you agree. I appreciate your POSITIVE FEEDBACK. and carpet would be best.

B-O-A-T Break Out Another Thousand

Be aware that polyester resin ("Fibreglas") dissolves polyurethane foam. You need to use epoxy resin over PU foam. For this, you need to use cloth (woven roving) because the viscosity of the epoxy resin makes it difficult to completely wet out mat.

Notwithstanding that there are thousands of reinforced resin clad plywood boats there is a marked tendency to delaminate due to the difference in coefficient of expansion ('glass/plywood) and also the swelling of the plywood - should it get wet through a bolt hole or screw.

If you decide to go the plywood route, you could consider true marine plywood (not for sale at Lowes). Look up the nearest vendor of Bruynzeel (usual disclaimer). This product has been around for over half a century - and there's a reason for that - although it is a tad expensive. Bruynzeel is of a West African wood called "Okume". There is also available a plywood of "Meranti" wood reputedly better than Okume but I have no experience with that product.

I am suspicious of the effect that treated plywood chemicals would have on the bond strength. Better go bare.

A point of vulnerability is the seam where the cockpit sole meets the vertical. I think that your Rhino idea is brilliant. It seems to solve all of the problems. Reconfirm it is compatible with a Lowes plywood substrate.

This is not correct!

It is downright wrong, in fact!

Maybe you mean polystyrene foam. As in Styrofoam.

I don't have any beef with using epoxy resin instead, but don't confuse the issue.

You are absolutely correct. What I recall as the "great centerboard trunk fiasco" involved the application of polyester resin to STYROFOAM

Old-Salt must be taking a nap somewhere!

Not napping, although that is always a good idea. Was out sailing on my Sunfish, about the most fun you can get from any sailboat!

Need more information to make a good suggestion. What are the materials of construction of the other parts? Is this in an cockpit in the open or an semi-enclosed or enclosed cabin? Will the area be open to the elements? Will there be holes in it for fittings/posts, etc. to pass through it? What type of boat is it? What is it used for work/pleasure? What size is it? Does the floor have any bends/curvatures to it? Is the floor located above the water line? Is it in the heavy moisture/wetness/water of the bilge? What was the old floor you are replacing made of and what finish did it have on it? A few others would be good also.

PT marine plywood is the only type that should be attempted and even that may have problems. The biggest difference between the very good grades of interior/exterior plywood and marine plywood, such as A/C or A/B is the inner plies of the marine are filled and there are no voids within them. This is especially important along the edges of the plywood. There may be gaps on the int/ext that go from the edge to the center or entirely across/lengthwise of the sheet. Obviously this is a problem you don't want. PT ext. plywood has the same problem. For this reason I would not use it except on a work boat that will be given a lot of floor abuse. Another big problem is the VERY EXPENSIVE COST OF PT MARINE PLYWOOD. A 4'x8' sheet of 1/2" or 3/4" untreated fir/spruce costs over $100/sheet. If you decide to use any type of PT plywood make sure you dry it in a cool dry location for at least a month or more. They are going to be wet and need to dry before putting a finish on them.

Sand well before finishing. An appropriate primer and one-part polyurethane paint is OK to use since it is now the lowest grade of marine paint readily available. For the upper side of the floor board eventually use an anti-skid compound (looks and feels like sand) either mixed in the paint prior to brushing or after brushing by shaking it from a salt shaker. Before painting fit and temporarily install the floor. Remove it, paint, dry and reinstall. Make sure there are no cracks or scratches in the paint. After installing, paint over all screw holes and screw heads. Best to fill over them with some sort of trowel cement (an old term similar to marine wood filler) and repaint these spots.

If you are going to use fiberglass DO NOT PAINT ANYTHING UNTIL AFTER ALL GLASS HAS BEEN PUT ON AND CURED. Any paint will substantially lessen the holding power. Either paint after the glass is installed or if you are real good put a pigment in the final coats for the color you want. If you glass make sure you use stainless steel screws to install the plywood. Anything else you can afford will present corrosion problems later on.

Personally, unless this is a work boat which I expect to replace the flooring every couple of years, I wouldn't install this. There are much better choices for recreational and fishing boats, both in strength, wear characteristics and longevity.

What is done is entirely up to the boat owner and what he is satisfied with. I would not use rhino. Doesn't work well with the flexing of wood.

Good Luck, Old Salt

****Brainstorming**** How about this. Using NO plywood. Use the insulation as a base and go between the runners and lay fiberglass between the runners (long ways). Fill up runners by laying mat and build up to 1/2" thickness. After it dries (layer per layer) becomes a solid fiberglass floor eliminating any chance of rot (no wood). Attaching it to the runners would make it very solid and you can do runner at a time. If a runner has to be replaced ( which it don"t) Lowes has a PVC board 1" thickness (varies size and lengths) - has a lifetime warranty and will adhere to fiberglass. Finish product will be smooth because you can sand - then paint - or overlay with carpet. Overall object is to have a fiberglass solid floor. Might be a little more expensive. What do you think?? Comment

BOAT - Break Out Another Thousand

Sailor Rick!

Before we all go any further in our pursuit of the suitable material for your boat floor we need some very important information. Information which could mean the difference between a great floor or a totally unsuitable installation that was a waste of money, labors and time.

What type of boat are you talking about? from post #8--->

Need more information to make a good suggestion. What are the materials of construction of the other parts? Is this in an cockpit in the open or an semi-enclosed or enclosed cabin? Will the area be open to the elements? Will there be holes in it for fittings/posts, etc. to pass through it? What type of boat is it? What is it used for work/pleasure? What size is it? Does the floor have any bends/curvatures to it? Is the floor located above the water line? Is it in the heavy moisture/wetness/water of the bilge? What was the old floor you are replacing made of and what finish did it have on it? A few others would be good also.

Nautical wise, we might be speaking of the sole or grate but certainly not the floor. There is no floor on a boat. Also need more description of what you are calling a "runner". Do you mean the portion of the frames that the bottom planks/plywood are fastened to? You would NEVER want to fill in that portion of the bilge with insulation that has been fiber glassed or anything else. Do not do what you have proposed in #18. It will not work for several reasons, several very important reasons. There is no kind of boat suitable to have that installed on it.

Before you go any further give us more information. Without it you will definitely be making your boat a bottomless bucket for your wallet. Many of the responses are somewhat good and many are trash (no offense intended to other contributors) that will waste your time, money and probably your boat forever. Your life and that of your family/friends could conceivably depend upon what you do to that boat.

Start with: is this a 8' pram or a 75' heirloom cruiser with all polished brass and rubbed cold varnish or something in between? Does it use a thumb in the water or a taffrail log or a pitot tube or a fancy GPS device for speed measurements? You can't get good answers without good questions. Do yourself a favor, give us more info!

Good Luck, Old Salt

1. 16' fiberglass Ski Barge boat. Since it is A BOAT not a Heirloom Cruiser, it has a floor if it was bigger then it would be called a DECK.

2. The foam that is in there is the same foam used under decks at marinas which are now outlawed in many states.

3. Fiberglass does not shrink - is waterproof - and will seal any hole FOREVER. Otherwise they would not make boats with it.

4. The boards that are in the middle are called runners by the boat manufacturers. Under floor is runners. Above floor is guides. At least what the manufacturers are calling them.

5. Cost wise marine plywood is VERY EXPENSIVE. I have talked to Bass Cat & Ranger Boats and on some of their boats THEY are using the same concept to a degree as what I am planning,-. Although they form and spray boats with fiberglass with mat.

Thank you or the additional information about the boat. This will get you more applicable and better answers.

Nautical terms, including the parts of a boat, seldom have the same meaning as "landlubber" terms. Those that have been presented concerning the boat, including the manufacturers, apparently are landlubber terms or ones unique to that manufacturer(s). Very often almost identical terms mean very different things. Example, a fireboat puts out fires but a fireship creates fires intentionally. A plank is the boards on a scaffold but also the boards the make up the hull of a wooden boat.

floor (n): 1) The bottom of the ocean. Seabed. 2) A transverse member mounted across the keelson of a wooden boat tying opposing frames and keel together. (usu: plural.

sole (n): The deck of a cabin or cockpit

A Heirloom Cruiser is a boat not a ship unless it is a relatively large ocean going vessel.

Fiberglass does not last forever. Go through a boat yard that has older fiberglass boats and look at all the cracks in hulls, gel coats that have faded or worn off, etc.

Marine plywood is very expensive but it is very good. You get what you pay for compared to other materials.

Runner: Checked with at least ten nautical searches and the closest found was a "Rum Runner". Also checked with design personnel of boat yards that do extensive and complex modification and repairs. The closest they could come to it was a "wave runner".

Its your boat, you can do with it whatever you want to. Just don't blame CR4 if it doesn't work out or doesn't have the life you were expecting out of it. Nautical terms for boats/ships are more explanatory than "landlubber" or a "local terminology". I don't make up the nautical terms nor do you. Use what there are to describe boats/ships and you get what you really want.

http://www.seatalk.info/cgi-bin/nautical-marine-sailing-dictionary/db.cgi?db=db&uid=default&FirstLetter=s&sb=Term&view_records=View+Records&nh=12

Good Luck, Old Salt

old salt,

It is a, "16' fiberglass Ski Barge".

In other words, it's a boat with a floor, terms the landlubber would use.

I've sailed on ketches and sloops, got lost below deck on the QE II, and only knew what a sheet was when I was told.

Let's just use terms we all understand.

lyn-

Well taken. Personally I am not a purest of nautical vocabulary, but when describing parts of a boat it is often better to use specific terms and not landlubber terms that could mean numerous different things. As in my original post, better questions get better answers. More information was needed in the OP to do even a fair job of recommending what would be best. This could be easily seen by some of the answers. Just trying to illustrate how ambiguous questions get poor answers and the better the question the better the answer. Same as saying "The Winner of the Preakness" or "American Pharoah" .

The term 'Ski Barge" is a good example. Doesn't look much to me like a barge that would be secured to a Moran tug boat. Also it was only popular for a short period of time and was mostly a regional design.

After a long winter I still have to remind myself that "port and left" mean the same and are shorter words than "starboard and right". Now about the term "Larboard"..............

Good Luck, Old Salt

Thank you and I WILL NOT BLAME CR4. I appreciate all the replies. I spent 8 yrs in the Navy and was on every type ship they have (Admiral's staff - jump from ship to ship every week) (5 Med cruises - 3 trips to Cuba - PR - Virgin Island & etc). You are right about different names of things.

I am just not wanting to use plywood. This is my 3 boat that has had issues with wood rot and I got rid of them. The idea with fiberglass I think will be great because it will be covered up with carpet not exposing it to the sun. About the foam issue - I am giving that much thought also. When I took the floor out of the boat the whole sheet of fiberglass that covered the plywood came off in one piece. I am going to cut into strips and lay them on top of the insulation that way I should not have an issue with it. Plus I will be getting rid of the waste that I would have had to throw away anyway. I am also only going to seal each section so that water cannot get into the channels. Wires had been laid down loosely under the flooring which I am going to run in PVC pipe. This should last me for 10 more years at least!!!!

Lyn

Just finished the transom. Fiberglass the transom twice then the boards that I cut for the transom I also F-B. Then I liquid nailed the board to the transom and then LN the board to board. Then FB the 2 boards to the transom and extended it 6" around the sides. The transom is SO STRONG that I can pick up the boat by the back tie down straps and NOTHING GIVES. To the lake and checked for leaks before I start putting the flooring in. Not one speck of water. Next week - Insulation (foam) and then start laying FB down long ways in the runners. I am impressed so far and am making great progress. I did use a whole can of resin on the transom and 2 packs of mat on purpose.

Sailor Rick

I would not use plywood...Nylosheet, flexiteek, Plasdeck, or any of the many specialty products offered...

Wait a minute.

Let's not build a deck for a yacht when we're talking about a dingy.

My friend just put a floor in his 12' aluminum boat.

Let's get some perspective here.

Sailor Rick, how about some details?????

Sorry about being gone so long. I will comment later.

All traditional plywood is made from peeling some kind of comparatively lower lignin,higher cellulose/hemi-cellulose wood. Whatever the interlaminary glue, the wood itself is inherently not suited to the marine environment, even if it is called marine grade.

About two years ago at a commercial flooring exposition I saw a piece of plywood made from shredded bamboo reconstituted with some form of polymer binder enveloping all of the fibers and binding the cross layers. It was represented as having minimal shrink-swell in various immersion cycles, good UV resistance, comparatively low flame spread, good surface abrasion and was exceptionally strong in the various structural properties. All I can remember is that it was made by a Japanese company...and it was not cheap...but it was very attractive.

***Brainstorming***** How about this. Using NO PLYWOOD. Use the insulation as a base and go between the runners and lay fiberglass (long ways). Fill up runners by laying mat and build up 1/2" thickness. After it dries (layer per layer) becomes a solid fiberglass floor eliminating any chance of ROT (no wood). Attaching it to the runners would make it very solid and you can do runner at a time. If you have to replace a runner (which I don't) - Lowes has a PVC board 1" thick (varies in sizes and lengths) has a lifetime warranty and will adhere to fiberglass. Finish product will be smooth because you can sand - then paint - or overlay carpet. Overall result - solid fiberglass floor which is my objective. Might be a little bit more expensive but.... Any comments?????

BOAT Break Out Another Thousand

If your heart is set on wood, then start your search for the latest and greatest here:

http://cenews.com/post/7282/consortium-receives-grant-to-explore-use-of-bamboo-as-an-urban-construction-material

It appears, as usual, that 'OP has left the building'.

Pre-Prime all your wood with a 2 part penetrating epoxy first. It soaks in well (viscosity approx that of diesel fuel). Once dry, it acts as the best primer you can get. I use Smith's, although Jamestown has it and also a company know as Dr. Rot, (same stuff, re packaged.) Spoke with a fellow , on a team of shipwrights, who helped restore an old 100 ft schooner on the East Coast, and they went through 55 gallon drums of the stuff. As a carpenter, former shipwright, and a Craftsman house restorer, we use this penetrating epoxy on ALL exterior wood, as a sealer and a wood restorer. All windows get surfaces and edges done twice, as well as doors, sills, trim, porches, lookouts, exposed beams etc. Also , a great site is Progressive Polymers…Be careful..Once into this site , you will find it hard to leave. Lots of boatbuilding info and products as well as other uses. It is out of New hampshire and he ships all over. Enjoy your project.

****Brainstorming**** How about this. Using NO plywood. Use the insulation as a base and go between the runners and lay fiberglass between the runners (long ways). Fill up runners by laying mat or cloth and build up 1/2" thickness. After it dries (layer per layer) becomes a solid fiberglass floor eliminating any chance of rot (no wood). Attaching it to the runners would make it very solid and you can do runner at a time. Lowes has a PVC board 1" thickness (varies size and lengths) has a lifetime warranty and will adhere to fiberglass that can be used for runners if any are bad which none are. . Finish product will be smooth because you can sand - then paint or overlay carpet. May cost a little bit more but then I would have a fiberglass floor which is my whole objective. Now what would be better Mat or Cloth ????? Comments??

Unless you are using 6 Lb. density or higher foam, the composite will weigh a ton.. Plywood is fine, and as others have mentioned , stiff, light , easy to work with..I have poured in so much foam , but not in structural areas. Is weight an issue? If not, just go to 3 / 4 inch marine ply, or 1 / 2/ inch , depending on the distance between the supports., and epoxy primer seal both sides. drill a few holes, pour expansive urethane foam and be done with it. All of the other layup methods, and complexities are time and money consuming. Go to Glen - L, and see what they have on their site--Good company , been around for years, and deal with a lot of plywood construction boats.

Aren't most rhinos on the endangered species list?

Yes you can apply it, but do you really want something that mud fence coyote ugly on your boat?

Look at my other replies about using fiberglass runners. The guy at rhino said that they can spray a floor in it and it would be very smooth. Most people think of bed liners which are hard and rough but the technique that they use in boats is a different technique and truck shops do not know how to do the procedure. I decided to not go that way because I would still have to put wood in it and I DON"T WANT WOOD in my boat to rot out again.

B-O-A-T Break Out Another Thousand

UPDATE ON BOAT FLOOR - Well I did not get away after all from wood in my boat. I did end up using 1 x 10 boards and fastened them down to the runners. I hated the idea of using wood BUT!!!!. The reason that I used 1 x 10's was because if I ever had problems with a weak floor - all I would have to do is replace one (1) board . I fiberglass generously over the top and sanded down any rough areas - not many - pretty darn smooth. I put in 2 drains off the floor in the back which allows any water to drain out. There is NO POSSIBLE WAY for water to get into the bilge area because each compartment is sealed individually. AS far carpet - I am going to use carpet with rubber backing from Cintas. These can be gotting in 5' widths and 12' lengths. My boat is only 16'. The other part I will have a platform on that is 4' wide. I can take up the carpet when needed and in winter time. Makes cleaning a breeze. Can spray out boat also. The console will not be a problem because it will attach to the innerwall. I think that I have well planned this out. After a few uses out in the water I will see how everything works. My cost is approx $350. NOT BAD!!!!!!!!

Just letting you know how the floor went in the boat. I ended up using 1 x 10 boards for the flooring. I DID NOT WANT TO USE WOOD BUT !@##$!@#$. I sealed all of the compartments of the bilge so that they are WATER TIGHT. Then I put the flooring down and fiberglass generously. Had a few rough spots to sand down but nothing serious. I put 2 holes in the back of the transom even with the floor so that water would run out. Sealed very well. I will be painting the floor and then for carpet I will be using throw rugs down that I can buy from CINTAS. The size 5' x 12'. Leaves 4 foot which I will be reinstalling the platform on. The carpet has rubber backing. I can easily roll up or take out and spray off. This makes maintenance very easy. The reason that I went with 1 x 10 is because if I ever have a problem with the floor, then all I have to do is replace just one (1) board and not a whole bunch. The console will be reinstalled to the innerwall which will not be a problem. I'm sure that I will have to make some changes (designs) as I use the boat but that will be simple. I have approx $350.00 in the repairs. Pretty cheap AND THE BOAT IS SOLID.

Congrats on the completion! Congrats on the use of wood, the first material used for boats, floating logs. I'm a somewhat pessimistic boater, for good reasons, keep an eye on those WATER TIGHT bilges. Nothing in boating is without risk (Murphy's Law of Safe Boating).

Enjoy the time on the water!

Good Luck, Old Salt

Good show!

Nothing wrong with wood. If it is allowed to dry after getting wet, it will last a long time. Any photos?

Now, one question about semantics. You said, "Then I put the flooring down and fiberglass generously".

As I said earlier, "fiberglass" is the cloth/matt/chopped strands that are dry until wetted with the liquid resin, either polyester or epoxy.

So, is it just the liquid that you painted on to seal the wood, or is it a "layup" of glass fiber and liquid resin.

Happy sailing in either case.

Don't be a stranger.

I used resin over mat (not cloth). I would say that it is about 1/4 to 3/8" thick with resin. Did not feel that I would need to add cloth to it. Am I wrong?

No. If it's smooth that's all that matters. The courser surface of the mat will probably be better when it is wet. Less chance to slip.

Cheers.

I feel that I got away with the repair rather cheaply do you think? Also I have not taken any pictures yet. I thought that I might wait until I get it totally finished. The only picture that I do have is one where it is totally stripped to bare ribs. Just a reminder of where this boat has come. Will be a surprise when it is totally done.

All that counts if that you like it.

After all, where boats are concerned money is no object. (As long as the wife doesn't find out)

Sounds good. Nothing wrong with wood as long as it has a chance to dry out if it gets wet from time to time.

I did have a problem with the motor mounts in my bow rider where the manufacturer had glassed over the plywood boxes that formed the pedestals for the mounts. Water got into them but didn't dry out very well. They should have drilled drainage holes along the lower edge. Long story short, the plywood eventually rotted and the engine mounts dropped down about two inches before I noticed the problem and by then the gimbal bearing was trashed.

Created new pedestals by bonding sections of pressure treated 4x4's and cut to fit the hull profile, etc. Now solid wood, and only glassed along the bottom edge with no gaps or pockets to hold water. Should outlast the rest of the boat.