First floor repair ever... (help me not screw this up!)

[Sixdekkers]

I apologize if this isn't the right forum, i didn't see one for "repairs".. I have a 70's 16' Larson I just got for fishing. Outboard, V-hull.

Issue:
i found a soft spot. i pulled the carpet back and found that someone had drilled a few small holes whenever and water seeped in rotting a area. seems about 24"x12" or so. the glass wasnt adhered to the wood there and crackling up, and squishing some water up from the soaked plywood underneath,

Sooooooo... seeing as how thats obviously needing to come up i took my skill saw and cut just deep enough to go through the glass a little larger than the bad area, and removed the glass.. then did the same with the water soaked rotten plywood. i hope this was right?? i just couldn't see glassing more glass over water soaked plywood that was rotten..

now... i can see foam (that seems a little water soaked, is this ok?) and also a stringer (?) .. that has a kinda soft spot but small and not through and through..

so pros, what from here? do i toss in a piece of good plywood, and just glass over it, or is there more painful summer ruining work ahead?

[Sixdekkers]

you get the idea...:(

[lazeyjack]

if it were me matey, I would get on ebay and buy another, better, bigger and with no problems, and have a happy summer get on the briny, fishing rod at hand, slab of beer, and , nice bird and there you are, no more worry

[jimslade]

How much do you like the boat? Its a lot of work. The stringers are probably gone and the transom too. Major work, but can be done. Lots of grinding and itching. Most cheap boats are soft and rotting.

[Sixdekkers]

Ok i think everyone got the wrong idea, this is NOT the whole floor.. its one side, one spot, and the section is only 24 inches x 12 inches total and thats with over cutting to get to dry solid wood all the way around..

[SamSam]

Screw some cleats on the underside of the floor around the edge, toss in a piece of good plywood, screw it to the cleats, and just glass over it.

[Bergalia]

With SamSam on this - but try and put opposing bevels (scarfs) on the 'new' insert - and the existing decking, to give that little extra strength to the repair.

[SamSam]

With SamSam on this - but try and put opposing bevels (scarfs) on the 'new' insert - and the existing decking, to give that little extra strength to the repair.

I was going to suggest that but it didn't look like enough room for the saw. It wouldn't be too awful hard to do though, even if some of it had to be done by hand and it wouldn't have to be an exact fit with the cleats to back it up.

What it means Sixdekkers, or at least what I mean, is the hole in the floor would have say 45 degree sides and the ply patch would have 45 degree sides so the patch could sit in the hole by itself without falling through even if the cleats weren't there. The sides would be buttered up with thickened resin to fill spaces and then the patch screwed to the cleats, then the works glassed over.

[the1much]

they say that once your foam has been water saturated that its useless after that, gives no boyancy, and they( engineer wonders) say it should be replaced. and how "much" water has been in there, does it look like its been a swimming pool for awhile? i'd want to find out if it was jus regular seeping or if i had a water prob,ie-leak, or if my sump pump wasnt workin correctly

[USCGRET/E8]

A couple years ago I removed all the saturated foam from under the floor on a Correct Craft ski boat. It probably weighed at least 500 lbs.

[Sixdekkers]

cleats? what are they?

[Sixdekkers]

Samsam-
i don't have the room for a saw to do a 45 on the side near the innner wall, and that sucks because thats the side that only has foam and no stringer near the wall..

i can get cleats, anyone got a picture of how these are installed?

USGRET-
the center strip front to rear of the boat is hollow under the floor, with foam on the sides only it appears, and only finding wetness on the damaged side, i went back to the sump / drain plug area and drilled a small hole at the lowest point going into that cavity, and maybe a cup of water came out, thats it, although the foam still is kinda wet.. i talked to a boat shop by my work, their tech said patch it and glass it, he said that the foam will never lose the buoyancy..

i suppose i could go drop it in the water and see if it lists from extra weight :D

[Sixdekkers]

just found this cool page, for anyone with foam questions..

Pour Foam FAQ's

Q. How do I know how much foam I need to float my boat?
A. Great question! Get your calculator ready, you will need it. A cubic foot of foam will float about 60 pounds of "dead weight". The wood parts of your boat will probably float, so you don't need flotation foam to offset that weight. The fiberglass parts of your boat will barely sink, so you really don't need much foam to offset the fiberglass- maybe one cubic foot of foam per two hundred pounds (or more) of fiberglass hull. The metal parts of your boat are what you really need to account for. A small (4-6hp) outboard may weigh 45-55 pounds. A 50hp outboard will weigh about 200 pounds.

So a 16 foot fiberglass skiff with a 50 horse outboard will need about six cubic feet of foam to keep it afloat. A 12 foot plastic kayak will only need one cubic foot. A 30 foot fiberglass sailing sloop with a diesel engine and lead keel would need about 150 cubic feet of foam. Actually, very few 30 foot keelboats have positive foam flotation, but it's not out of the question- especially when you consider all of the air pockets that would exist, as well as all of the wood interior components that provide some positive flotation.

Q. Do I need to paint or fiberglass over the foam?
A. You can, but it's generally not necessary. Urethane foam will absorb a small amount of water, because some of the the cells are open (95%+ are closed, though). Painting or glassing will seal the foam and prevent any water absorption, but it really shouldn't be necessary unless the foam is constantly immersed in water, such as in a boat with bilges that are always wet. The foam is not UV resistant, so it should be painted if exposed to sunlight.

Q. Is the urethane foam resistant to fuel, oil, and solvents?
A. Mostly yes- It is resistant to gasoline and diesel fuel, although it will absorb a small amount because no pourable foam can be guaranteed to be 100% closed cell. A strong solvent such as acetone or toluene would eventually break the foam down, but it would take a long time.

[SamSam]

Samsam-
i don't have the room for a saw to do a 45 on the side near the innner wall, and that sucks because thats the side that only has foam and no stringer near the wall..

i can get cleats, anyone got a picture of how these are installed?

You could do a 45 with a chisel or something, it doesn't have to be perfect. Thickened resin would take up any spaces.

You might be thinking of the wrong kind of cleats. What I'm talking about would be say 1" x 3" x ?? lengths of wood that you would glue and screw to the underside of the hole so half the width (1 1/2") of the strips/cleats would stick out and they would form a lip/ledge around the hole that the patch would sit on. The patch would then be glued and screwed to the cleats also. Do you see what I mean?

[the1much]

you could 45 it with a jig-saw, they have blades made just for fiberglass,, they thick ones that look like they got a bunch of dirt glued to em, and pretty cheap for a pack

[Sixdekkers]

You could do a 45 with a chisel or something, it doesn't have to be perfect. Thickened resin would take up any spaces.
Do you see what I mean?

ok i see, basically supports underneath. I thought you meant cleat nails. The only problem with that is theres no room unless i chisel out foam. Ill figure it out. I just applied the crystallizing epoxy to the small soft spot on the stringer and that stuffs sweet :D

how do i make thickened resin? just add more hardener?

[Sixdekkers]

well i got my plywood cut perfect, and there seems to be a slight warp needed for the piece, and right near the side wall where theres nothing to run a screw into either, :rolleyes:, figures, so i will have to use some sort of cleat that goes from under one side all the way to the other side hence having to carve out some foam..

[alan white]

Samsam-
i don't have the room for a saw to do a 45 on the side near the innner wall, and that sucks because thats the side that only has foam and no stringer near the wall..

i can get cleats, anyone got a picture of how these are installed?

USGRET-
the center strip front to rear of the boat is hollow under the floor, with foam on the sides only it appears, and only finding wetness on the damaged side, i went back to the sump / drain plug area and drilled a small hole at the lowest point going into that cavity, and maybe a cup of water came out, thats it, although the foam still is kinda wet.. i talked to a boat shop by my work, their tech said patch it and glass it, he said that the foam will never lose the buoyancy..

i suppose i could go drop it in the water and see if it lists from extra weight :D

Of course you don't have room for a saw. You must use a 40 grit sanding disc on an offset grinder and cut the angle that way, using the edge of the disc (whick will get right into the corners too). A good eye and a steady hand will approximate 45 degrees. Then adjust the patch to fit so that it lies 1/16" below the surface, allowing a thickened epoxy to create a good bond between the two mating surfaces. Maintain the exact height required using two sticks across temporarily drywall-screwed into the patch. When it cures, use the grinder again to sand a six inch by 1/16"-1/8" deep dish along the four sides, epoxy some mat into that, and then grind and fair and glass over the whole thing.

Alan

[the1much]

ok i see, basically supports underneath. I thought you meant cleat nails. The only problem with that is theres no room unless i chisel out foam. Ill figure it out. I just applied the crystallizing epoxy to the small soft spot on the stringer and that stuffs sweet :D

how do i make thickened resin? just add more hardener?

they have all kinds of stuff for thickening, i use stuff called Fiber Fill,, its a powdery substance that you mix in your resin till it gets the thickness you want, ie; like a bondo type paste <sorry for the "B" word

[Sixdekkers]

so let me get this straight, you thicken it to fill gaps/mating surfaces? does that harden and bond better like that? my glass skills are amateur and start and end with the Schucks box of resin/hardener with cloth:D :P

[SamSam]

You must use a 40 grit sanding disc on an offset grinder and cut the angle that way, using the edge of the disc (whick will get right into the corners too). A good eye and a steady hand will approximate 45 degrees.
Alan
Yes, that will work good. I didn't think of grinding, as it is always a last resort for me. I think it may be a good thing to do at Guantanamo.

[the1much]

so let me get this straight, you thicken it to fill gaps/mating surfaces? does that harden and bond better like that? my glass skills are amateur and start and end with the Schucks box of resin/hardener with cloth:D :P

you thicken it to fill gouges, gaps, used as a filler. you shouldnt need to thicken it just to lay mat. it doesnt make the bond any stronger, it just makes a really hard filler;)

[Sixdekkers]

well i went to the local boat supply and the people there are very uninformed :( they knew nothing of a thickening product.. and i do have some gaps to fill. i am using a polyester resin according to the can. i just laid my seal coat, i can do another before i do cloth if i know what will mix with it to thicken it.. :confused: and i have decided to just go this route til salmon season ends in January then gut the floor and foam totally the right way..

[Bergalia]

well i went to the local boat supply and the people there are very uninformed :( they knew nothing of a thickening product..


Poida swears by roo **** - and that's probably widely available in WA. But personally I'd use a spoonful of 'flexible' car body-filler well stirred in - or even a small measure of talcum powder (choose perfume to your preference) :)

[alan white]

As said, your patch ought to be glued with thickened epoxy. If you are using polyester exclusively, don't bond the patch with it. It is not an adhesive. Without epoxy, the patch should be screwed down, meaning cleats as mentioned before. A simple 45 degree bevel will only work with epoxy--- thickened because edges soak up so much, and cuts may not be accurate.
It is fine to laminate mat and glass over the patch with polyester.
The thickening material can be fine sawdust (as produced from 240 grit sandpaper). You can buy this "wood flour", but then, if they have wood flour, they probably also have high strength filler powder or microballoons, or various other micro-materials like micro-fiber. Talcum powder is at Wal Mart for cheap.
If it's just for the season, patch OVER the hole and use construction adhesive and screws. Five minutes.

Alan

[the1much]

well i went to the local boat supply and the people there are very uninformed :( they knew nothing of a thickening product.. and i do have some gaps to fill. i am using a polyester resin according to the can. i just laid my seal coat, i can do another before i do cloth if i know what will mix with it to thicken it.. :confused: and i have decided to just go this route til salmon season ends in January then gut the floor and foam totally the right way..
stay away from that boat store,, any boat place should know about cavasil<prob wrong spelling, try an auto body place, and remember, not this time because u say it gonna be jus for season, but when you do a final patch, use filler after you mat, never mat over filler on a final job, everything,filler and mat, will crack. and another thingy,, dont forget to sand between layers of mat if its been over 24 hours since the last one, within 24 hours you'll still get a chemical bond, after 24 hours you need to grind and make mechanical bond

[Sixdekkers]

You can buy this "wood flour", but then, if they have wood flour, they probably also have high strength filler powder or microballoons, or various other micro-materials like micro-fiber. Talcum powder is at Wal Mart for cheap.
Alan
Thats what they had but the guy didnt know what they were for :rolleyes:

Its all good i decided since im going to just use it til November then gut it so i dont have waterlogged foam, I went ahead and filled with the "B" word, sealed again, then laid matt, its now the strongest part of my floor :D

time to go fishing...

[jimslade]

stay away from that boat store,, any boat place should know about cavasil<prob wrong spelling, try an auto body place, and remember, not this time because u say it gonna be jus for season, but when you do a final patch, use filler after you mat, never mat over filler on a final job, everything,filler and mat, will crack. and another thingy,, dont forget to sand between layers of mat if its been over 24 hours since the last one, within 24 hours you'll still get a chemical bond, after 24 hours you need to grind and make mechanical bond If you use an unwaxed resin, you can bond to it as long as it remains tacky, usually 30 days. Waxed resin always needs a mechanical bond. Cabasil and talc are good fillers. Patches are best done with epoxy.