Help!! Fixing rot in floor.

[detchon]

I have a 1994 Rinker Captiva 170 with a Mercury 115 outboard. I decided to change the carpet on the floor and when I stripped it all off, the floor under the captains chair is completely rotted. The section is about 12" by 18". I tried looking underneath the floor to see if I could see any cross beams but it is completely full of spray foam and I can't see anything. I need some advice on how to replace this section of floor.
Also, the whole inside is covered by a layer of fiberglass. How do I replace the fiberglass after I have fixed the hole?
I have attached some pictures.
Thanks for any suggestions.

 

[drewpster]

Re: Help!! Fixing rot in floor.

First do a good assessment of the extent of the damage. The best method in my opinion is to do some drilling in the deck around the rotten area. It may not be necessary to drill very deep or to use a large bit. You also want to be careful not to drill through the bottom of the boat. Be very careful at the edges of the deck and pay close attention to the deadrise where the deck meets the side of the hull. It is very easy to go completely through in these areas. In fact, stay clear of these areas altogether when drilling.

The idea is to take a good core sample of the area using a small bit. Go just deep enough to penetrate the fiberglass and a little in to the wood core. I would start at the perimeter around the rotten area and work out ward until you find good wood. If you get wood dust out of a hole, your good. If you get wet, black wood out of a hole that's bad. After you get an idea of how extensive the damage is, we can move forward with a way of fixing it. Don't get to worried about it, it can be fixed. But you need a good idea of how extensive it is.

 

[dozerII]

Re: Help!! Fixing rot in floor.

If you can drill some 5/8" holes in inconspicuous spots through the floor, then using piece of 1/2" copper pipe take core samples of the foam to see if it is water logged. This will tell you if the stringers and wood are surrounded by water.
Glen

 

[Cadwelder]

Re: Help!! Fixing rot in floor.

Not to be the bearer of bad news, but you'll be extremly fortunate if you don't have totally rotten stringers along with that deck. Heed the advice above and take good samples throughout.

 

[Yacht Dr.]

Re: Help!! Fixing rot in floor.

Also try not to drill into any tanks that might be lurking under there .

YD.

 

[detchon]

Re: Help!! Fixing rot in floor.

Okay, I drilled holes and at the moment I think I am lucky because it appears that the extent of the damage is limited to an 18" by 18" square. The foam underneath looks fairly good and it looks like the rot is just in the floor board.
Now how do I proceed?

 

[idonthaveaname]

Re: Help!! Fixing rot in floor.

Now how do I proceed?

Telling you how to proceed is not a one step answer. Obviously, you'll need to remove the rotted wood, cut a pattern and replace it. You will also need to ensure there is proper bracing, the wood is prepared for marine/water use, probably glass the floor area you've torn up, etc. There are many threads here that will show you what others have done in similar circumstance, but you're going to have to search around. There are also a number of books on the market regarding fiberglass work, wood replacement, decking, etc. Here's nice link to start with;

http://www.fiberglassics.com/restoration/book-part-2-transoms-floors-and-stringers


Also, look below in the Similar Threads box for others with similar problems. Enjoy and don't be afraid to post more pictures.

 

[Bob_VT]

Re: Help!! Fixing rot in floor.

You can just get by with a patch if it is limited damage. There are multiple methods you can use.

These will all require fiberglass or epoxy to seal all your wood from future rot.

You can use plywood and make pieces to support a new deck piece and apply that resins. Your deck needs to be cut at a 45 degree angle to support the repair piece. OR you can consider replacing the entire deck section..... your choice.

 

[Woodonglass]

Re: Help!! Fixing rot in floor.

Here's how I would do it. First cut out the rotted area with your saw beveled @ 45 degrees, making SURE that there are NO obstacles of any consequence underneath. This beveling will make the patch stronger when you apply it. I would then try and determine if there is anyway to get support to a stringer. Since the Captains Chair depends on this portion of the deck it is critical that it be rigid. If the Foam does in fact make contact with the deck then this will aid in the support issue. I would then use 3/4" cdx plywood and cut some 4" wide cribbing strips. Coat them with epoxy and glue and screw them to the under side of the cut out. leaving a 1 1/2 " stub out. I would then fabricate the patch to match the hole and the thickness of the deck. I would coat the patch with a couple of layers of 1.5 oz fiberglass mat on both sides and edges and use either epoxy or poly resin (Poly is cheaper, epoxy is stronger.) I would use epoxy. Make sure to allow enough space for the mat and resin when you make your patch. It's ok if you have a 1/4" gap. You can use some thickened resin to fill the gap and smooth things out.
Click on Pic to see what I am talking about.


I'm just sayin...

 

[SawDust{RM}]

Re: Help!! Fixing rot in floor.

I would ripp up all of the carpet to make a full assement, I took my Donzi all the way down to the hull except the foam & had to cut out the stringers with a chain saw, the factory foam job musta been done on a Monday as there were alopt of empty spaces, I only was going to see what was up with the fuel tank & fix the floor & carpet, if I hadn't been going after the fuel tank I would had never noticed the stringers were rotten just wet, but the tank was foamed in & no drainage so I was getting water in the top from the sending unit, I had to chip all the foam from around the Tank, thats when it was apperent the whole thing was shot, better if you pull the carpet so you will know what you have & work from there, if you do have to replace the floor I would suggest using Plascore, simply glass both sides of the plascore, do any refoaming, screw it into the stringers with stainless screws, glass it all in & recarpet, then you will never have a rotten floor again. If it turns out you only have that small spot to fix, you can use a mixture of Resin/BondO/chopp to fill the void you create.

"Never Go Straight, Go Forward"

 

[Yacht Dr.]

Re: Help!! Fixing rot in floor.

Yea..I did not see Any rot in the pics ( especially pic 3 looks fine to me ).

I would cut some strips of ply ( 4" wide and length needed ) for the underside of the cutout.

There called "cleats" ..

Resin coat them and then bed them down with 4200/5200 under side of the cutout deck ( half of the cleat exposed to the hole you cut out ) using SS screws.

Fill the hole with treated ply then screw and glue this square ply to your cleats.. Apply 1 or 2 layers of 1.5 oz mat/resin over the Whole 18x18 repair Scab.

PM me if you have any questions.

YD.

 

[oops!]

Re: Help!! Fixing rot in floor.

yeah.....yd has it.........we call them backing flanges.

ok.....

now.....you are not done your inspection yet. .....the top of the foam allways looks good......but not underneath.........get a 2 inch pvc pipe and cut 2 "teeth" in one end.....drill the pvc pipe on a angle so you get down toward the stringer hull joint......and just pull it out....push the foam in the pepe out and look at the bottom where the teeth are.....this is a core sample.....dry? (most likely)....re insert and fix (ill expand on YD's method)

wet?....BAAAH HAAAA HAAAA....(sorry could not resist)

ok.....your damage is most likely caused by the screws from your seat base not sealed in the wood.....they just drilled the holes, screwed it down and that was it.....each hole in the deck is an entry area for water.....they need to be sealed with the proper stuff.

dig out a little foam around the area of your hole....if its 12 x 12....then dig out a bit wider underneath. (this is to give room for your backing flanges)
add the backing flanges....i would screw them into the deck as well as 5200....(again...do not use bare wood, seal it with something and each hole you drill...fill with 4200 then add the screw..
now its time for your patch.....glass the underside of the plywood....add 5200 all the way around your flange.....and drop in the patch....drill and screw it down....again....seal the screw holes.

glass over the whole thing....i would use one csm and a 1708 6 ins wider than the patch (this is for added strength for the pedestal seat) lay your carpet.

there is one other thing you can do if you want...before you glass the patch in,,,and after its screwed ...using a small hole saw.....cut a hole directly in the center of the patch...keep the cut out. shoot spray in foam in the dug out area...let it expand out of the hole. ....re insert the cut out....seal with 5200 and then glass the patch in.
the foam will give added support under the repair...(not much....but some it will also re seal the foam)

now....do the other seat base !!!!!!

re carpet....done

 

[tyblack]

Re: Help!! Fixing rot in floor.

It looks like I will be needing to inspect my foam underneath my deck once I get in there. I'm stuck with the total black wood after I had ripped up all my carpet and peeled back the fiberglass off the deck. Great info on your post that I am taking notes on.