Chris wrote:

Howdy all,

I've got some visible cracks at the bottom of my hull on my 16ft runabout.
This past summer when using the boat I was getting a bit of water in it
after having it sit for a while in the water (the bilge pump easily took
care of it). I'm now thinking that these cracks may be the cause and water
slowly seeps into the boat.

Now, my question about how I should attempt to fix this giving the following
considerations 1. It's an old boat. 2. I use it a 4-5 weekends a year.
3. I don't want to spend a lot of money as its not worth it.

My ideas have been the following:

1. The ugly job
- rough up the area around the crack and put a few fiberglass patches on
it (poly resin & cloth)
- paint over it

2. Cleaner job
- grind out the crack and a bit of the area around it (make a V)
- fill with fiberglass resin, or epoxy resin using a filler
- not sure if a cloth patch on top of this would be necessary.
- paint over it

What do you guys think given the considerations?

Close, no cigar. Grind the Vee on the outside, feathering out 5
times the thickness of the glass, leave it rough. Wash it with
acetone. Laminate several layers of glass, starting with a narrow
strip, covering with wider strips until you fill up the Vee. Smooth
and paint / gelcoat. Wet the glass, but try to use more glass and
less resin. Squeeze the bubbles out (don't mix the goo too
vigorously, just thorougly) using a serrated roller made from 2
sizes of washers loose on bent threaded rod with locked nuts. Clean
tools with acetone.

You should also do the same on the inside, or could just lay a
couple of wider strips on the roughened inside, where you can,
washing the cleaned inside with acetone before laminating.

You will find polyester strong enough, if you get enough thickness
and surface area covered and well bonded. Epoxy would be stronger,
but is overkill, and will make the question of refinishing the
exterior gelcoat into a can of worms, because poly gelcoat doesn't
stick to epoxy, so you would need to redo the entire hull with epoxy
paint to achieve a Bristol appearance.

Polyester Gel coat is just catalyzed polyester resin with pigment
and a little thickener, like silica gel, or, I am sure others have
their favorites. You can brush it on with several / many thin
freshly mixed coats applied while the hull is still tacky and buff
it flat and smooth. It is self levelling, especially if you can turn
the boat so you are painting on the level. If you get a good colour
match (on the bottom? who cares?) you won't be ashamed of it. Don't
use bondo, it just isn't as good as it could be, with automotive
fillers, etc.

Are you sure the cracks go right through? If so, gring the crack a
little beyond the torn glass. You may only want to redo the gelcoat,
if that is as deep as they go.

Water collects in boats, even condensation can get inches deep, and
rain could be getting in, too.

Terry K