I have a 2003 H356 which has lots of hairline cracks on the coach-house roof, particularly on the port side. see picture example. Does anyone have a similar issue & is there a good fix. I am thinking I may need to re-gelcoat the entire surface.
Gelcoat cracks
- Thread starter Lance Dias
- Start date
Is the cabin top soft there? Does it flex when you step on it? Is that the only spot with those spider cracks? Thinking sun angle at dock.
Spider cracks like that aren't generally a problem other then looks, but they may indicate an area with poor support such as degenerating core when they appear in a place like a cabin top. Often you see them where cabin and cockpit seating come together or other transition spots.
Minute flexing is usually the cause, but UV can also contribute. Or, there's a minor flaw from the factory.
It isn't usually hard to gel coat over them. Sometimes, the underlying cause will reassert itself.
- Will (Dragonfly)
Spider cracks like that aren't generally a problem other then looks, but they may indicate an area with poor support such as degenerating core when they appear in a place like a cabin top. Often you see them where cabin and cockpit seating come together or other transition spots.
Minute flexing is usually the cause, but UV can also contribute. Or, there's a minor flaw from the factory.
It isn't usually hard to gel coat over them. Sometimes, the underlying cause will reassert itself.
- Will (Dragonfly)
The spider cracks are in the non skid portion , it appears. It is very difficult to replace that to look like the original.. and pretty expensive. I would consider just resurfacing the entire nonskid area with a product like KiwiGrip.... I recently covered all my non skid with it.... my old decking was worse than yours...and I was very pleased.... made the 40 year old boat look like new.
Another popular method is to cover the areas with a tile like product such as this Treadmaster.
If you google "yacht non-skid systems" you will find many choices.
That said.... I would not be afraid to try brushing on a thinned primer that will sink into the cracks... then finish with a similarly thinned coat of non skid deck paint.... if that doesn't work to your satisfaction you can go to the cover method.
Another popular method is to cover the areas with a tile like product such as this Treadmaster.
If you google "yacht non-skid systems" you will find many choices.
That said.... I would not be afraid to try brushing on a thinned primer that will sink into the cracks... then finish with a similarly thinned coat of non skid deck paint.... if that doesn't work to your satisfaction you can go to the cover method.
Last edited:
Thanks Guys & the deck is rock hard which is good. I understand spider cracks are usually caused by rough treatment of the deck (or hull) when the manufacturer is removing the item from the mold or, something hits the fiberglass. In my case, I have the cracks all over the coach house top & unsure what caused it apart from a defect in manufacture.
Kiwigrip looks interesting even though its water based. I would be interested to hear from other H356 owners on their experience.
Kiwigrip looks interesting even though its water based. I would be interested to hear from other H356 owners on their experience.
Cracks like you show are quite common on sailboats your age. They are most commonly found at curved surfaces and I believe that they are mostly cosmetic cracks in the gelcoat. It has been said that you can fill them but that they will return. I have some on my 1997 h40.5. Wish it weren't so, but that's life.
My last boat had a bunch of cracks on the cockpit floor. I used kiwi grip. It covers finer cracks. If the cracks have wide crevices, say enough you could stick your fingernail in you should fill them first. It’s been 4 years and still looks great.