Rookie repair. Fiberglass floor repair

[uffdabock]

Hey all.

I have a BeeCraft 15' Tri Hull Fiberglass boat that I have inherited 8 years ago. It has been stored outside and over the years developed a crack in the floor. The rest of the boat is in fine condition and I plan on getting this boat out to sea as soon as I make some minor repairs.

Here is some pictures of the crack.
http://i.imgur.com/yJi4Q.jpg
http://i.imgur.com/Qaopn.jpg
http://i.imgur.com/VFauk.jpg

As you can see the floor was already repaired with some kind of sealer, which must have been done a long time ago because my family has owned this boat for 15 years now. We used it for ~7 years, got it wet maybe 50-60x and it was a great all purpose boat. Sadly, our family has had no vehicle to tow it over the last 8 years.

I purchased this Fiberglass Resin kit from Farm n Fleet and the clerk there said it should be acceptable to use on my boat's floor even though it was marketed for auto repair. The boating store I visited beforehand sold a very similar kit for 4x as much. As long as the floor is sealed and is smooth I will be satisfied. Here is the kit I bought.
http://i.imgur.com/rsL7I.jpg
http://i.imgur.com/3DvYI.jpg

I have been seeking a guide on how to properly use fiberglass resin using the mesh. Does anyone have a link to show me or some general tips? Thanks in advance, much appreciated.

Chris

[lewisboats]

Before you slap resin on there I suggest you open up that crack and see what the plywood floor underneath looks like. I had something similar and had to tear it all out because the crack(s) allowed water to infiltrate and sit and rot the ply flooring underneath. The water also migrates away from the crack and tends to find resting places in pockets and hard to get to spots. Also look for rusting fasteners and possibly waterlogged flotation foam. If the boat was at an angle (to drain) check out the transom area too as the water would pool in that end, under and around the drain hole.

[pauloman]

Lewisboats comment above is right on the money. Need to see if any damage inside before surface patching.

paul oman

[CDK]

The cracks suggest that something under the glass fiber has expanded and contracted several times: probably the plywood underneath.

Lewisboats solution surely doesn't make you any happier, but it is the best way to proceed.
Check for soft areas where the floor sags when you stand on it. If there is one, cut a large inspection hole there; you can close it later with a piece of plywood if you've found the rest of the floor in good order and the bottom is dry. If it is wet and moldy down there, you have no option but to remove the whole floor.

[pauloman]

you will need to get the inside core as dry as possible if it exposed and wet. One trick is using rubbing alcohol which will blend with the water and evaporate away much quicker than just the pure water. By the book repairs for bad core material is to remove and replace, but most folks (even industry insiders) usually inject low visc epoxies that will bond to wet or damp surfaces. - But keep in mind there is no fix to rotten wood except replacement.

[CDK]

Originally Posted by pauloman

One trick is using rubbing alcohol which will blend with the water and evaporate away much quicker than just the pure water.

Fortunately that statement isn't true, because if it were Jack Daniels and Four Roses would contain only 12-14% alcohol instead of 43%.

Methanol and ethanol can be mixed with water in any ratio but evaporate much faster; because the air at the surface of such a mixture is saturated with alcohol, the evaporation of the water is even slowed down.

[PAR]

Plywood can't be effectively "dried", the glue lines prevent the moisture from having an escape route except through the relatively small surface area of the exposed end grain. I've seen water soaked plywood remain water soaked for over a year, and this was in the Arizona desert, where you'd expect the best conditions to evaporate out the moisture existed.

As an example, a full sheet of plywood has 64 sq. ft. of surface veneer area, but just a few sq. inches of exposed end grain, for the internal portions of the panel to "vent" moisture vapor.

This is why you have to hack out the plywood most of the time. Yes, many will use stop gap measures, such as drilling a thousand holes on 2" centers all over the area and injecting some magic goo in a can, but frankly this is a stop gap technique really just postponing the inevitable. I have opened more then my fair share of hulls, just to find a pool of this magic goo, all hardened up in the bottom of the bilge, having run right through the repair area and to the lowest point of the boat.

Use the search tool and look up previous threads on sole, floor and stringer replacement.