Fiberglass Boat Floor Replacement

[nielbales]

Hey All.. I just purchased a 1969 Larsen Bowrider Tri-Hull. Hull is in fair-Good condition, and I'll be re-painting and filling and repairing fiberglass in some areas. The Floor however was soft and needed replacing. Can anyone tell me whether or not I should clear out all the foam??? What should I use to replace it?? As you can see in some photos, some has come up already, but in cleaning up and trimming back the glass, I found more, and it's pretty water logged. Any suggestions?

 

[KnottyBuoyz]

Re: Fiberglass Boat Floor Replacement

If it's got water in it, it should be replaced. There are two part pourable foams that are USCG approved for flotation.

 

[nielbales]

Re: Fiberglass Boat Floor Replacement

I guess "Great Stuff" Spray Foam is out of the question???

 

[Tail_Gunner]

Re: Fiberglass Boat Floor Replacement

Yes, some will agree but that foam was never intended for that type of use try US composite's.......Do a search under foaming you will have hour's of reading

http://forums.iboats.com/search.php?searchid=660112

 

[nielbales]

Re: Fiberglass Boat Floor Replacement

Thanks Tail_Gunner. I've looked at many posts and sites abou the projects. I'm working on a really tight budget compared to some and didn't expect I would have to change all these "unexpected items". I'm working with My Home Depot and Lowe's on this project, Butget doesn't allow Marine Supply.With all the other items I replaced I really can't spring for it.

Is there some way I can go about replacing the Stringers as a temporary fix until I can re-do the entire floor?? Stringers are wet - Solid... but wet none-the-less. . 1 side is worse than the other. Port Side Stringer is Slightly worn down.Looks like they used a 2x8 Stringer Glassed into the side of the Bilge(center Hull).

This is my first Boat repair, but I'm typically pretty handy... Found a great resin Fix for the Deck too.. I'll share that as my progress follows along.

 

[JB]

Re: Fiberglass Boat Floor Replacement

For gosh sakes replace that floor with a deck. Boats have no business having floors.

 

[KnottyBuoyz]

Re: Fiberglass Boat Floor Replacement

For gosh sakes replace that floor with a deck. Boats have no business having floors.

The only floors on a boat (or ship) are the bottoms of tanks!

Ceiling = Deckhead
Wall = Bulkhead
Floor = Deck
Kitchen = Galley
Bathroom = Head
Hallway = Companionway
Door = Port
Window = Porthole (portlight)
Basement = Bilge

Yadda yadda yadda

The only "rope" on a ship is on the ships bell. Do you know why a porthole is round? So water doesn't hit you "square" in the face!

If you want cheap flotation nielbales before you put the new deck in place put some empty and capped pop bottles (2 quart/litre size) in the space and foam in place.

Good luck.

Rick

 

[Wtrlogd]

Re: Fiberglass Boat Floor Replacement

I noticed the cosst is an issue but Keep in mind the flotation is critical to the strength of the hull. You can sometimes dry out the stringers by brilling 1/2" holes in a few inches every foot or so and giving time to dry. Then repair the holer by filling with some resin.(polyester will work). As for the foam, the pourable stuff is really pretty cheap. You can seal the bottom of your new deck with resin and chopped mat the drill a series of 1" holes and pouring in the foam. Then you cover the holes when you glass in the deck. Here is a link for the foam.
http://www.mertons.com/Floatation/index.html

 

[F14CRAZY]

Re: Fiberglass Boat Floor Replacement

Is it true, that with a trihull, you could skip stringers and just pour structural foam underneath the new deck? I read about this here somewhere and said its possible because a trihull has tri's (lol) that those make the hull rigid

 

[nielbales]

Re: Fiberglass Boat Floor Replacement

It's true the HUll is very rigid, but I dunno if I would go without the stringers. It did make them alot easier to replace, when I had a old pro come by for some help, showed me exactly how to cut them and replace the sections with the cuts in the least stressed parts. But be sure your glass is perfect, and tight, no room for gaps in the cuts, needs to be poured perfect. so there's no "wiggle " room. I'll upload photos of the progression when I can.

I'm pretty close to the finished product... should be any day now. Just gotta paint the hull, is it bad to use enamle based, or should I go with the bottom coat? What's the benefit of one over the other?

 

[SurfsideJim]

Re: Fiberglass Boat Floor Replacement

I am working with a 14' 1972 "Surf Side" tri-hull and have it down to the hull now.
A local boat repair person here told me to use non-pressure treated wood instead of pressure treated wood on the flooring, because he said that the fiberglass may not stick to the chemicals used during the pressure treating process. Instead, he said to take resen/hardner mixture, thin it with acetone, then apply it to regular plywood FIRST letting it soak in good and cure, and especially to edges of the wood. The lay floor and then apply fiberglass over the wood.

Does that make sense?

IF any experts out there have used pressure treated wood, which brand?
Also, does it have to be "Marine Grade"?

 

[Andy in NY]

Re: Fiberglass Boat Floor Replacement

Read this thread for the debate of doing a stringerless job using 4lb foam.
http://forums.iboats.com/showthread.php?t=263121

 

[lowkee]

Re: Fiberglass Boat Floor Replacement

I'm working on a really tight budget ... Is there some way I can go about replacing the Stringers as a temporary fix ... Solid... but wet none-the-less

I think many of us begin our first resto (maybe every resto) the same way.. here is a my top 10 list for resto projects for your enjoyment..

The 10 steps of restoration denial:

1. That soft spot just needs a patch
2. The foam will dry out once I seal the deck
3. It's just the deck, the stringers are fine
4. i don't have to pull the engine; I can work around it
5. The transom feels solid
6. I won't have to remove the cap, plenty of room
7. i will just buy a couple of gallons of resin
8. $1,000 is plenty for a job like this
9. I should be on the water by the end of the month
10. I need a beer! Nothing is going as planned!

Restos aren't cheap and cheaping out on them will probably cost you more in having to redo it shortly thereafter. Save up and do what you can when you can. Your life is at risk on a mickey moused boat, especially without foam.

 

[PiratePast40]

Re: Fiberglass Boat Floor Replacement

^^^^^^ - ditto

 

[rjrottari]

Re: Fiberglass Boat Floor Replacement

I also have a 1970 Larson and i also had to remove all wood and foam. Do you have photos as to how you re did the stringers and did you pour foam around them after?

​

 

[Inherited-a-hulk]

Re: Fiberglass Boat Floor Replacement

I recently inherited an old tri-hull, so old it doesn't even have a nameplate on it, but it has many of the problems talked about here. I have already removed all the interior carpet, decking, and floatation foam, then had to cover it for the winter. There doesn't appear to be any ribs or stingers in the bottom of the hull, the structure was made up of the hull, filled with foam, then plywood decking glassed in all over and around.
problem is now, since its a bow-rider with a walk-thru windshield, the consoles have sagged from the decking rotting out over the years. How can I "lift" the consoles back into place so the windshield will close properly? I know I need to lift them to install new decking under the front fiberglass floor area, but what do I brace against to jack them up? any ideas anyone? Help!!!

 

[COB]

Re: Fiberglass Boat Floor Replacement

Love to see what you're doing heree to!