Easy way to seal some cracks in gelcoat / surface causing rain to leak into cabin?

[jimTheSailorMan]

My little $500 boat has some spider cracks in the gelcoat that cause the closed up boat to leak rainwater into the cabin. Worst place is a small storage area that looks like a live-well. Has a 1" round hole which I put a rubber stopper in but the storage area drips rainwater into the cabin through the cracks.

Will silicon caulk work?

Without doing a complete rework of the gelcoat, what is a what easiest way to seal these cracks - a 1 year solution is ok.

[Sailmonkey]

If you’re leaking water through spider cracks in gelcoat into the boat, you’ve got more than spider cracks.

It may be that a fitting that has caused flexing and become loose needs to be re-bedded, but don’t use silicone. The problem with silicone is that it contaminates the surface to the point where nothing else will adhere unless the silicone saturated area is removed (ground out).

[travellerw]

Yes, what Sailmonkey said. Its not possible for a spider crack to leak water. A spider crack is a crack in just the gelcoat, with the fiberglass underneith being intact.

Like he said, your leak is probably from somewhere else.

[jimTheSailorMan]

Originally Posted by travellerw

Like he said, your leak is probably from somewhere else.

Maybe I used the wrong term - it's a series of small cracks that propagate through the fiberglass thus allowing water to drip through. There is no structural load - not sure what cracked this in the past but I sat in boat in the backyard during the rain and watched it drip through at this spot.

[gmakhs]

The easiest and cheapest way is to fix with fiberglass, can you provide some photos ?

[Terra Nova]

Originally Posted by Sailmonkey

If you’re leaking water through spider cracks in gelcoat into the boat, you’ve got more than spider cracks...

This. You need fiberglass repairs, not silicone caulk.

[rbrentp]

I am about to get yelled at for giving bad advice. There were key words in the post. $500 dollar boat, last for a year. Silicon is definitely bad.


There is a plastics two part superglue. There is also the regular stuff. If you drip it in, it will build a strong bond and effectively seal the area.


Best thing to do -no, permanent - no.


If they are small enough to look like spider cracks it can work - short term - and does not give the headache in later repairs like silicon.


Yes I have done it. Yes it worked for about a year...probably a heat cold cycle.

[FionaJC]

If it is a really narrow crack that leaks then Captains Tolleys is a useful start but its the nature of the cracks that's important. Definitely needs photographs. there are cracks and then there are cracks.

[travellerw]

Since this is a 500 boat, then I think this is a great learning experience for you.

Now without pictures, we can't really make an accurate suggestion, but I think I understand your problem. If it was me, I would take this opportunity to learn how to do some fiberglass. It sounds like this problem could be solved by a couple of layers of fiberglass on the backside to seal up the crack. After that, you can decide if you want to try a gelcoat repair to fix the cosmetic issue on the top.

Again, its a $500 boat, why not use it to learn on.

[guyrj33]

smear polysulfide caulk in the cracks. LifeCaulk is my favorite polysulfide.

an alternative would be to apply a layer of fiberglass over the area, if using epoxy resin paint over the repair to provide UV protection to the epoxy.

[ramblinrod]

Originally Posted by jimTheSailorMan

My little $500 boat has some spider cracks in the gelcoat that cause the closed up boat to leak rainwater into the cabin. Worst place is a small storage area that looks like a live-well. Has a 1" round hole which I put a rubber stopper in but the storage area drips rainwater into the cabin through the cracks.

Will silicon caulk work?

Without doing a complete rework of the gelcoat, what is a what easiest way to seal these cracks - a 1 year solution is ok.

If the mechanical stress in the area have caused cracks through the fibreglass, there is no adhesive -sealant on the planet that I know of, that will fill the cracks and stop them from reforming.

It would take an inspection of the actual cracks to recommend a proper solution that will last long enough to warrant your time and effort to execute.

Got photos?

(Inside and out.)

[roverhi]

You've got spider cracks radiating from a hole. These cracks allow water to seep around a cork you've stuffed in the hole. Do I have that right??? If that's the case Liquid Life Caulk or the Captains stuff may solve the problem.

Other caulks may work but only use sillycone if you don't like yourself. It's a crappy caulk that seeps into the gelcoat and makes having anything stick to the gel coat in that problematical. It is also notorious for losing it's adhesion and leaking. It is hard to work with because it skins so quickly and clean up/removal is a mess as solvents won't cut it. To remove you have to carefully scrape it off to bare glass which is time consuming and then lightly sand the area to remove residue that has migrated into the glass before you can use a real caulk or paint the area. Sillycone belongs in boobs not boats.

[jimTheSailorMan]

Here are some photos

Looking from back of boat - area with old plywood hinged cover is the storage area that's leaking




This is what the plywood cover looks like: - it has a long piano hinge holding it on.

Finally, looking down into the storage area - noticed that somebody tried to fix this before. Feels like home latex caulk (not silicone). Top right has a stopper I added to plug the 1" hole. Red rectangles show the cracks with previous caulk repair and where it leaks into the boat cabin.



Is this to store anything special. Cover feels weird since you have to stand or put a foot on it when dealing with the boom/mainsail. I don't really need the storage since the whole cabin is empty but I would rather have good footing when reaching for the sail / boom connections to the mast.

Wonder if reason for cracks is somebody might have used it as a stepping point in the past?

[Bleemus]

The leak is caused by rain getting past that poorly fit plywood lid.

I bet that was designed as a cooler. The hole you plugged should have the ability to attach a hose to let the melting ice to drain to the bilge.

[jimTheSailorMan]

Another picture - area around windows frame leak too but I think I can fix those:

Here's the boat