repairing boat floor

[fishinphyl]

Hey guys I need help. We have a older model Silverline fiberglass boat that has some soft spots in floor. I have a not very handy man husband. He wants to just put a new plywood floor with carpet over the existing floor - which is what a guy that repairs boats suggested also. But what kind of plywood? Is the treated plywood which you can purchase good enough or should it be treated with something else? Or do you have a better plan of attack? Thanks!

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Phyl

[Guest]

The easiest thing to do is just to go over the existing floor.The correct thing to do is to replace the floor.(I would be just going over the floor)The plain green treated plywood that you get at Menards or Home Depot will last a good long time but it is very heavy and will add a lot of weight to your boat.You can get marine grade treated plywood which is much lighter but costs about twice.There is a place in St Paul that you can get some,can't remember the name right now.(I will look it up if you need it)

[hydro]

Go with the plain treated plywood and don't waste your money on "marine grade" plywood. The marine grade specifies that it is made with the core veneers plugged to eliminate voids and other that that it is the same as ordinary plywood, same glue and veneer. The treated material will not rot (that's why your floor is "squishy") and when dry is the same weight as any other plywood of the same thickness. It is also easy to find locally.

If you are going to do the job, do it right. Disassemble the boat interior to the point where you can remove the old floor. Save it for a template and replace it piece by piece. You can re-carpet it with exterior grade carpet from the local home store. Use "Pop" rivets instead of screws wherever possible.

I did the floor in my 17' Alumacraft a couple of years ago and while it was a big job, it really was not that difficult.

[Surface Tension]

Your going to speed up the rotting peocess by covering the old floor up. It will never dry out when it gets wet. In time all your fasteners holding the new floor on will fail also.
Pull out the chairs and make a template of the floor out of tar paper. Remove the floor. Note all the points where the new floor will be screwed to. Put your seams on these points. Also note where your seats will be and decide if you might need more backing to keep the new or old ones from tearing loose.When you have the floor tore up replace the wiring and any hoses.
Buy 5/8ths or 3/4 green treated plywood ahead of time to allow time to dry out. You can buy stain made for green treated plywood. I would use it on the top side only to help it to stop sucking up water when the floor get wet. Dont put plastic to try and keep the foor dry , you will just trap moister.Buy a good outdoor carpet that will breath. Any wood will rot or delaminate if it stays damp and cant dry out.
After you have the floor cut out and dry fitted then carpet it. Wrap the carpet around the edge's. Pull and staple the carpet to the botton side. Use the longest stainless steel screws you can to fasten the floor.

[wastewaterguru]

OK, I'll ask the stupid guy question.

Is the existing floor wood or fiberglass?

If it's a fiberglass floor in the fiberglass boat (which seems more likely to me) then I would cut out the softening fiberglass to prevent the softening from continuing. Then I would repair the hole (if less than a foot) with a fiberglass repait kit or insert a cubby or equipment locker. Sand and paint the entire floor to match.

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John K., a.k.a. wastewaterguru
Prior Lake, Minnesota

[hydro]

Here's another thought- use an inorganic board for the flooring. Try Space Age Synthetics in Fargo or Recycled Plastics near Alexandria for materials. Both of these companies produce board mterials that can be used for boat flooring.

[cdnfisherman]

Phyl

I am currently doing the same project as you guys. Actually just brought the boat in the garage to thaw this weekend.

My boat has a fiberglas floor with weak spots. I bought treated plywood and outdoor carpet. My plan is to tear the old carpet up, and lay the new plywood floor on top of the old fiberglas floor.

I will glue and carpet the plywood before laying it down.

I plan to take up this project this coming weekend. If you want me to let you know how it goes, I will post here when it is completed.

By the way, I purchased all the carpet/plywood/glue at Menards for under $140. A cheap fix that will last a few years until I can afford the new boat!!

JC

[fishinphyl]

Hey you guys are awesome!!! I will pass on all of the above to the husband - and then run! You see this is my boat and he is not exactly fond of fishing. I assume the floor in it is plywood but don't know if he has checked it out. We purchased new seats for it last year and did not screw them down because we knew we had to do this, so that saves a little bit of work. Now the big problem is that he was layed off all winter and didn't get it done - but he got called back to work today - ask me how happy I am? Oh well, just hope the marriage can survive another home improvement project! Summer better get here pretty soon!

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Phyl

[Guest]

The thing about fiberglass boats is that the floors are most times not only screwed in but set on the stringers and foam core in a bed of resin(glued),then a layer of fiberglass and resin is layed over the floor.If your boat is older they more than likely used polyester resin which is not completly waterproof.Minor cracks and the resins allow moisture in but trap enough to start the rotting process.Today they use epoxy resins that are more resistant to water and moisture.
Standard green treated plywood will breath to let out the moisture and will not rot.It is actually designed to maintain a higher moisture level than standard plywood even after it has dried further from the time you bought it,and will be heavier than standard or marine plywood.The kind of marine plywood I have had access to is treated and rot resistant.Again this may not be an option as the price is expensive.If you plan on keeping the boat for many years rip out the floor and replace it with new marine plywood set in a bed of epoxy resin.If you do this I am sure you will find that you may need to replace some stringers also and may even want to check your transom.Otherwise just lay a new floor over the old use it for awhile untill you get the bug to get a new boat.I am sure the easy fix will last as long as the rest of the boat.

[Surface Tension]

You mean you dont know how to get you hubby to do things for ya. Geez my wife uses her secret weapon. You got one too.

[This message has been edited by Surface Tension (edited 03-25-2002).]

[fishinphyl]

So Surface Tension what size club does she use?

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Phyl

[cdnfisherman]

Fishhead,

Do you have any ideas on how to strenghten the transom? I have noticed that mine is not all that strong, but am unsure about how to fix the problem. I was thinking about strapping some kind of board across the back to spread out the weight of the motor. What are you thoughts here??

Thanks
JC

[Guest]

I had an old 72 trihull that had a bad transom.You could move the top of the transom about 2 inches and I did not trust it to hold the motor.the right fix would have been to tear out the entire transom and replace the rotting wood.This would have included removing all the fibergalss around it and essentialy taking the entire back of the boat off.More work and money than the boat was worth.So the quick fix was to strengthen it and prevent it from moving.I ran a 2"angle iron the length of the transom and bolted the top motor bolts through it.About 3"to the outside of the motor bolts I ran 1" steel square tubing(one on each side) from the angle iron through the splash well to another angle iron that ran under the front of the splash well.I did the same thing to the bottom of the transom at the bottom motor bolts with the tubing attached to an angle iron bolted to the floor. Painted everything up nice and pretty and sealed around the holes that the tubing ran through.The transom was stronger than it had ever been,even though most of the wood in the transom was rot.I used the boat for another five years and never had any problems with it.You may be able to get by by just using the angle iron along the top of the transom but I just tend to over build things.

[Polar Bear]

Screwed down 1/2" treated plywood right over the old floor on my 16' fiberglass boat 8 years ago. Covered it with carpet and haven't had a problem yet. One thing though: make sure you use exterior carpet glue (solvent based). The interior stuff is water based.
Polar Bear

[Valv]

Well, I did my SeaRay 26' last fall.
It had same soft spots, I ended up cutting out entire floor, cleaned up area and installed new treated 3/4" plywood which I covered with fiberglass first. It's not a tough job, just working with fiberglass makes you itch all over, so protect yourself. You can buy plain fiberglass resin and fiberglass mat at most auto part store, WalMart, Menards, Fleet Farm, etc.
Once you cover plywood with fiberglass it will be a tough waterproof shell around it.
Screwed new floor ove stringers (they are the long beams running back to front on bottom of hull) with stainless steel screws, then covered it all with another coat of fiberglass. Outdoor carpet or Marine carpet will finish job easily.

Leaving old rotten floor below it, won't help much since rot will spread more and weaken even plywood above it.

I know it doesn't sound a lot of fun, but many hubbys like it best if it has a case of favorite "brewsky" laying around. Just be sure to give it to him after he cuts boards....cutting lines will be straighter

One more thing, before you lay new floor, be sure to make some pass through holes on bottom of stringers, so water will flow easily to back of hull and won't re-rot again.

One more alternative is to visit a boat dealer, they have many great deals laying around, you know...a nice Lund with 4 stroke motor....

Gooood luck.

Val

[This message has been edited by Valv (edited 03-27-2002).]

[fishinphyl]

Thanks Val! I already figured out the beverage part of it - that is how I get him to go fishing! As for the new boat - well it took me long enough to work him into this one. I figure if he actually catches a couple of big ones MAYBE I can get a new boat. I really want one of those deck boats. Then he can sleep on the long seats and I can fish! Thanks so much everybody for all your advice. Now if I can just get this stubborn Norwegian to listen to them. He hates doing anything with a hammer and saw and complains for hours or days - depending on the job - before he can start on it. I just need to wear ear plugs.

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Phyl

[Surface Tension]

Sounds like you may need to use viagra along with the secert weapon.