Small Fiberglass Boat - Redoing the floor

ryanh487 · Mar 15, 2018

I recently made a trade and received a 14' 1991 G-Force Falcon fiberglass boat. The hull and transom are solid, but the floor has a large hole that the last owner very sloppily tried to repair by stuffing it with fiberglass fabric and pooring the resin over the top. It is letting water under the floor and causing further soft spots/rot. I'm worried that the fiberglass shells the seats are mounted on will disconnect under power and cause a safety issue, so I would like to replace the floor.

I'm thinking of removing the fiberglass floor entirely and using stained/sealed 1x4 slat wood decking (there are drain holes that would allow water to pass rearward to the compartment with the bilge pump, and gaps in the slats would allow standing water to evaporate) and mounting the seats on pedestals secured to the stringers.

My primary question is, how to I go about securing the stringers to the inside of the hull? Screws with marine sealant? What would the best material for the stringers be? Squared aluminum tubing crossed my mind but I've never done anything like this before. 1/2" thick PVC sheeting also crossed my mind, though I don't know how well it would hold up. (This stuff: https://www.homedepot.com/p/Veranda...llular-White-PVC-Panel-HDSHSM124808/301950563)

I'll try to get some pictures this evening and post them for reference.

Thanks!

WayneB · Mar 15, 2018

post photos and we can give more guidance.
Most boats are two or even three piece assemblies, remove the rub rail from the outside and begin separating the top cap from the hull.
If the floor is the third piece, it will remain once top cap is pulled, you will determine what fastening method they used then. Likely it was dropped into a bed of resin and will have to be cut out, but it may have fasteners hidden in the gunwales to spreaders. A magnet may help you find them if they were glassed over.
Be warned this is not a quick or easy undertaking, especially if you have never done it. Whatever you do, do NOT screw through the hull to mount spreaders to secure deck (not floor) to. This should be epoxied or polyester resin and glass cloth.

See if you can find a model and/or serial number on this hull, chances are there is some documentation out there that details how it was constructed, and how you can take it apart and repair it without guessing.

ryanh487 · Mar 15, 2018

Here are some pics

Full boat

Ugly repair job

Other floor pics

WayneB · Mar 16, 2018

Well, good news. it looks like a drop in deck

Pull off the rubrail and unfasten the track, and pull the topcap. Underneath you should see how the deck liner was fastened and secured to the hull.
Take the deck liner shell out of the hull and repair from underside, use polyester resin and glass cloth and glass mat. Flip right side upwards and strip and coat corners and deck to suit. Once cured out, drop 'er in and secure.

Bestest tool you could have is a 7-9 inch variable speed grinder with an assortment sanding discs with grits from 30 to 150 to scuff and remove resin. Everything else would be basic carpentry stuff, saw and maybe a router and orbital sander.

ryanh487 · Mar 16, 2018

So what you're saying is after I remove the rim from around the top (and probably the plumbing from the livewell) there should basically be a big fiberglass liner that pops out?

So i just pull that, cut a clean square around the ugly patch job, re-patch it with new fiberglass, then sand and paint?

At that point, would it be acceptable to secure stringers for a wood deck with sealed screws through the liner, or would I still need to glue them in place even though they won't be secured to the hull?

Would sealed 1x2s with 8" spacing be adequate to secure 1/2 sealed ply with carpeting or sealed 1x4's for decking, or should I use 2x2's?

WayneB · Mar 16, 2018

Pretty much.
As for the patch, cut back to unrotten wood and replace as needed. It will probably expand once you start poking it with a screwdriver or pick.
Once the deck liner is out, you can determine if you want to repair the deck or replace with something different.
If you want the look of a wood deck, I would consider a floating mat of decking that is friction fit to the inside of the deck liner, or omit the liner altogether, and secure somehow else.

WayneB · Mar 16, 2018

Some angles it looks like a drop in liner, others it looks glassed to the hull.
a couple photos from above may clarify it more better.
You could cut a hole with a holesaw near a corner and find out short of removing the deck cap.
Not a lot of info on this model boat.

ryanh487 · Mar 16, 2018

Yeah all I can find when I Google the brand and model is one newer used model for sale and a yacht company.

Here's some more pictures. Pressing on it and looking at how the transom is configured, it appears that the section on the bottom between the noticeable ridges is the only decking, and the ridges are the seems where it is attached to the hull.

WayneB · Mar 16, 2018

I think you're correct.
Holesaw near a corner and use a router with a straight bit to carve out the hole you want to repair.
If you can find solid wood near the edges, you can rabbet the edge of both the deck and your repair, and embed with resin. Be a strong joint.

Stroker · Mar 16, 2018

Looks like the whole floor was glassed in with a chopper gun to me. My biggest worry would be the condition of the floor, stringers and bulk heads under the fiberglass floor skin. If they are wood it is a good possibility they will be some damage from water penetration through the original hole in the floor and attempted sloppy repair. Been down this road several times, seen many more, quite a few were not worth the labor and material cost to save. BOAT=break out another thousand.

ryanh487 · Mar 16, 2018

It really doesn't feel like there are any stringers below the deck. It's almost trampoline-like, just a thin layer of veneer topped in fiberglass. It just feels like the deck is suspended about 1" over the hull and the platforms for the seats go through the deck and are attached to the hull itself.

I'm very tempted to strip out the entire deck, cut out the seat bases and livewell, and epoxy in a wood stringer system to secure some metal pedestals and then deck around them with 1x4's. Open up the floor area. This boat was bought with trout fishing the hooch and crappie fishing allatoona in mind, so a cooler will do for fish storage and a bucket with an aerator will do fine for crappie minnows.

WayneB · Mar 16, 2018

Stroker said:
Looks like the whole floor was glassed in with a chopper gun to me. My biggest worry would be the condition of the floor, stringers and bulk heads under the fiberglass floor skin. If they are wood it is a good possibility they will be some damage from water penetration through the original hole in the floor and attempted sloppy repair. Been down this road several times, seen many more, quite a few were not worth the labor and material cost to save. BOAT=break out another thousand.

thats what I was seeing, chopper gun in the mold, with some rolled in reinforcement strips at stress points.
Got a freind ( an exterminator) who picked up a cheap hull because it had termites. Total rebuild, no wood left.

Nothing is too far gone, if the price is right.
I wouldn't be afraid of this one, it's only 14ft and looks like a 4ft beam.

WayneB · Mar 16, 2018

3/4" plywood can span 30-32 inches without a lot of deflection.
We'll know more when you cut a hole somewhere.

Stroker · Mar 16, 2018

Old fiberglass boats rot from the inside out. There was probably water intrusion under the floor which rotted the plywood underlayment which gives the floor structural integrity. Once the underlayment rots away the thin fiberglass floor skin will delaminate and fail resulting in a hole in the floor. I've repaired some by cutting out the old floor, laying down new marine grade plywood and then fiber-glassing over it, others I've had to cut out glassed in stringers and/or bulk heads, glass new ones in and then do the floor. YMMV.

Stroker · Mar 16, 2018

A springy floor is a sure sign of underlayment failure. You need to remove the deck to determine the condition of your under floor structure. I have seen people repair your floor issue by laying new marine grade plywood over the top off the damaged floor and then glassing it in. They would throw some new carpet over it, reinstall the seats, and sell that sucker to a new sucker ASAP.

ryanh487 · Mar 16, 2018

Stroker said:
A springy floor is a sure sign of underlayment failure. You need to remove the deck to determine the condition of your under floor structure. I have seen people repair your floor issue by laying new marine grade plywood over the top off the damaged floor and then glassing it in. They would throw some new carpet over it, reinstall the seats, and sell that sucker to a new sucker ASAP.

Plan B is keeping the outboard and trailer and selling the boat only and use the cash towards a new 14' aluminum jon from academy lol.

Stroker · Mar 17, 2018

It is hard to sell a boat without a trailer. Aluminum is the way to go, if you knock a hole in it it is quick, easy to repair by someone with a TIG welder.

WayneB · Mar 17, 2018

Just picked my lil boat up from the engine rebuilder.

Stroker · Mar 17, 2018

Them 2 strokes sound bad when running on a hose. Had a neighbor who hated it when I ran mine.

ryanh487 · Apr 13, 2018

Sooo... exactly how much give should I expect in the exterior hull? I can push in a bit. Feels like the fiberglass is solid but there's either no backing or possibly rotten backing. Is it possible the hull is solid fiberglass with no wood interior or is this thing just trash?

Small Fiberglass Boat - Redoing the floor

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