Cracks in fiberglass of bilge area

[brendanstl]

I have my motor out for a repower and noticed a few small cracks in my bilge area in the fiberglass. I was pressing on the fiberglass to see how strong everything was when I noticed some cracks that were about 1 1/2" to 2" long, when I pressed on them some ugly gooey looking water seeped out, pressed on them for a while and got them cleared out, checked the bottom of the boat under the bilge area and everything is fine there (no cracks). To sum this all up I am wondering if there is a propper procedure for prepping and fixing this problem, I know that I need to use bilge paint to repaint after the repair is done. Any help and links to material would be appreciated.

The pic to the far right is a chunk of fiberglass I peeled off of the bilge area and it clearly has rotten wood beneath it. The bilge area only has a FEW spots in it that are soft and spongy the rest of it is solid and sounds good when you hit it or tap it.

 

[Mark42]

Re: Cracks in fiberglass of bilge area

That "ugly gooey" water is a bad sign. Before having the motor re-installed, drill some holes into the stringers and inspect the wood that comes out. Use a 1/4 or 1/2 in bit. My guess is that water has gotten into the stringers and is rotting them away. Not too hard to replace the stringers with the motor out.

Post some pics, and do some searches in the boat building and restoration forum on stringer repair. Might have some rot in the transom too.

 

[brendanstl]

Re: Cracks in fiberglass of bilge area

I'm about to go dump this boat in the landfill

 

[brendanstl]

Re: Cracks in fiberglass of bilge area

That "ugly gooey" water is a bad sign. Before having the motor re-installed, drill some holes into the stringers and inspect the wood that comes out. Use a 1/4 or 1/2 in bit. My guess is that water has gotten into the stringers and is rotting them away. Not too hard to replace the stringers with the motor out.

Post some pics, and do some searches in the boat building and restoration forum on stringer repair. Might have some rot in the transom too.

The cracks are in the floor area of the bilge. I would take it that the stringers are the boards that are laying on edge on either side of the bilge area that have the motor mounts connected to them?

 

[bhammer]

Re: Cracks in fiberglass of bilge area

The cracks are in the floor area of the bilge. I would take it that the stringers are the boards that are laying on edge on either side of the bilge area that have the motor mounts connected to them?

That is correct. They run the length of the boat. Like he said, they can be fixed but it is a chore. If you think you want to do it, look over in the restoration group and start reading. There is a good chance that your transom is rotting as well. You can drill some test holes to start looking as well as using an awl and start poking at wood. If it pokes into the wood, it is rotten and needs to be replaced.

 

[Mark42]

Re: Cracks in fiberglass of bilge area

From these two pictures, I am wondering if the hull is a sandwiched plywood/glass design. That is where the hull is fiberglass on the inside and outside, but has sheets of plywood between the glass layers.

The big problem with that design is once water gets in and rot starts, it is nearly imposable to repair because the entire hull must be stripped from the inside, new wood installed, then more glass applied. This is very difficult to do right. I believe that no one has successfully repaired a boat of this design in this forum because they collapse after the rot is removed, leaving a very thin shell of a hull.

The reason I bring this up is that little piece you held with rotten wood looks like it came from the hole in the bottom of the bilge, where the hull is usually solid fiberglass, and not from the stringer area.

If that is the case, do some exploratory hole drilling to see how bad it is. If it is a wood cored hull, it is time for a new boat.

Did this piece......

..... come from that black hole?

BTW, What make/model/year is this? Does it have twin V8's?

 

[Bob_VT]

Re: Cracks in fiberglass of bilge area

Why don't I slide this into the restoration section and a few pros will chime in..... the people who have been there and done that!

 

[brendanstl]

Re: Cracks in fiberglass of bilge area

From these two pictures, I am wondering if the hull is a sandwiched plywood/glass design. That is where the hull is fiberglass on the inside and outside, but has sheets of plywood between the glass layers.

The big problem with that design is once water gets in and rot starts, it is nearly imposable to repair because the entire hull must be stripped from the inside, new wood installed, then more glass applied. This is very difficult to do right. I believe that no one has successfully repaired a boat of this design in this forum because they collapse after the rot is removed, leaving a very thin shell of a hull.

The reason I bring this up is that little piece you held with rotten wood looks like it came from the hole in the bottom of the bilge, where the hull is usually solid fiberglass, and not from the stringer area.

If that is the case, do some exploratory hole drilling to see how bad it is. If it is a wood cored hull, it is time for a new boat.

Did this piece......

..... come from that black hole?

BTW, What make/model/year is this? Does it have twin V8's?

That is exactly where the chunk of rotten wood came from and it is wood sandwiched between the hull and the interior fiberglass but as I mentioned it is only rotten in a few spots the rest of the bilge area is nice and solid, the soft spots are only where the cracks were. I was thinking about just cutting out all the bilge area fiberglass this winter and replacing everything then re fiberglass and paint. Is it dangerous for me to patch these holes I have made now along with the cracks and run the boat for the season?

The boat is a 1989 Ebbtide Campione with a single 350 mag and alpha one outdrive.

 

[Mark42]

Re: Cracks in fiberglass of bilge area

If you believe the rot is only in a few spots where the cracks are, then go ahead and make a repair. Not sure how to go about cutting through the top layer without cutting through the bottom layer of glass too. Maybe a die grinder?

I would cut back to solid wood, and when laminating new ply back in, be sure to build up a few layers of CSM on the inside covering a larger area to help give the patch strength.

Once you start cutting in, you will have a better idea what the condition is.

If you make good patches, no reason it wont last many more years.

 

[brendanstl]

Re: Cracks in fiberglass of bilge area

If you believe the rot is only in a few spots where the cracks are, then go ahead and make a repair. Not sure how to go about cutting through the top layer without cutting through the bottom layer of glass too. Maybe a die grinder?

I would cut back to solid wood, and when laminating new ply back in, be sure to build up a few layers of CSM on the inside covering a larger area to help give the patch strength.

Once you start cutting in, you will have a better idea what the condition is.

If you make good patches, no reason it wont last many more years.

What exactly is CSM? I figured a die grinder would be a proper tool to use and I'll grind a half inch up from the floor of the bilge all the way around so I dont have to worry about going through the hull.

 

[Mark42]

Re: Cracks in fiberglass of bilge area

CSM is Chopped Strand Mat, or sometimes called just Mat.