gelcoat cracks and water leaks

[Rockter]

To my surprise, it looks like a series of thin cracks around the dorade "risers" are leaking. I am surprised, as only the gelcoat looks cracked, and with very thin cracks at that. All four dorade risers... three are shown here...

Image of North of Oban, heading North, Summer 2007 - Photobucket - Video and Image Hosting

....have got wee cracks running along the sides of the base of the risers where they meet the deck.

On the inside of the ship, close to the risers, you can see the water damage developing.

I am surprised that the cracks would get right though the GRP resin, but maybe I am wrong? It does not seem a highly-stressed part of the ship and the hull does not get worked hard.

It is a white paint on there at present, but the cracks are obvious now. I wonder what sealant would do it.
I am loathe to paint over the top of the cracks, but I may have to.

Thanks.

Rockter

[JHJensen]

Rockter,
Are your dorade boxes (what you call risers) screwed to the coach roof? I think you will need to remove the boxes and look underneath. I have seen this in the past on some boats where the screws were leaking or there was leak from a penetration under the box.

Are all four dorades leaking or just one? Can you access the overhead inside the cabin and see where the water is coming in or are you just dealing with stains on the headliner... if so you need to get above the headliner. Also what kind of vessel is she?

Testing with a hose and someone underneath in the cabin watch should help you fine the leak.

John

PS...Don't just go and start putting caulking on things....I see people do this all the time and it just makes the job of finding the leak more difficult

[Rockter]

JH :

Thanks.
The dorade boxes are moulded on there and don't have any formal fasteners.
The inside of the cabin roof is a series of teak stringers laid onto a painted roof. It is very pretty and I am loathe to take a crowbar to it as it will need skilled finishing to recover it.
The ship is a Union Polaris 36 ft, from 1977, one of the early ones, about the 7th of about 160, I think.....

Image of Crinan Canal Summer 2007 - Photobucket - Video and Image Hosting

It is 31 years old but there still there is a lot of boat there. It's a bit of a paradox that ship. Often you see really good workmanship and it certainly is a stable ship, but the build was fraught with the most awful short-cuts and the repairs have been agonising. They welded my stainless water tank without the obligatory chrome-rich electrodes, for example, and it leaked like a sieve. You want to try fixing that one in an afternoon, or 5 weeks.

[xort]

Is captain tolleys 'creaping crack filler' still available? It might be the solution

[JHJensen]

Rockter,

Sorry I was off there She looks like a nice vessel. This is the kind of thing I love to chase! To bad you are not in my neck of the woods!

The only other thing I would suggest is to put some paper towels inside the the box and then test again and see where the problem might be in the box. Are all of them leaking or just one?

Another thing to check for is any other hardware on the decks that is up hill from where the stains are appearing.... leaks sometimes travel.

Best of luck and do let us know what the story is. One of those things I like to keep in my notes.

Could also put a photo or two of the interior stains?

J

A possible repair which I have used in other situations is to clean the cracks with a dremel tool and then fill them and paint over. I know you don't want to do it but that may be the fix in the end.

It also maybe worth probing the cracks and opening some up to see what is going on.

[Rockter]

JH...

3 out of 4 of them leak. I am surprised that the gelcoat only needs to crack and the resin does not stop it getting in there.
I will take some pictures next time I am there. It's a 200 mile round trip.
I have been considering moving the ship a bit closer, perhaps to a 100 mile round trip. I need to do more maintainence.

[sailingdog]

I'd second this stuff. It's basically a very watery, low viscosity epoxy that will seek out cracks via capillary action and fill them.

Originally Posted by xort

Is captain tolleys 'creaping crack filler' still available? It might be the solution

[Rockter]

I will give it a try there Saildog. Have you had success with it? Given time, a drip cam nake quite a mess.

[Capnblu]

Rockter, the cracks you see in the gel around the dorades is due to the manufacturing technique of your deck. When the guy who laid up your deck sprayed in the gelcoat into the deck mold, he paid extra attention to all the little bumpy things in the mold and gave em all a real heavy coat. The next bunch of fellows came along and laid down a whole bunch of Fiberglass mat, or used a choppergun. Next some guy came and pressed some wood into and onto most of the surface, followed by more glasss and resin. Of all of the things in the sandwich they created, the gelcoat is the least flexible. Everything moves a bit, compared to the gelcoat. It cracks when it moves. You can waste your time trying whatever crack cream someone will sell you, but if you still have an uneven surface, Not completely uniform (like around a dorade, or where the cabintop turns up) you and everyone sooner or later will develop them little cracks. Thicker gelcoat = more bigger cracks. Thinner gelcoat = smaller cracks. The only way I know of getting rid of the cracks for certain is to sell your boat.

[Rockter]

I am surprised that if the gelcoat cracks, it leaks. I thought the resin and mat below it would continue fighting the leaks after that. At this stage I am not certain that's where the leaks are coming in, but I can see no-where else at present.
It seems so consistent around the dorades, that I looked for some common factor, and the fine cracks seemed to be common.
I will put a cover over it this week-end. Covers are not too expensive here in Scotland.