cracks in gelcoat

I purchased a used Scot manufactured in the mid-eighties. Bought it about four years ago; never sailed before so we are learning. Since, it has developed massive number of hairline cracks across the fore deck perpindicular to centerline. At one boat shop I was told that you don't usually get so many hairline cracks on a deck. more at corners and stress points. They said that when it happens it is usually because the gelcoat was applied too thick originally. Does anyone have any idea if this is true? Or other explanations? We've taken good care of the boat, always covered it, have hit the dock a few times coming in but nothing massive, my crew stands on the foredeck to tend to the jib. And in addition, what is the threat to the wood underneath?

Sounds odd. I have some hairline cracks, like crazing on my deck, but they are near the edge of the deck and they look like they are impact points, where the gunwale hit a dock or piling.

Harry Carpenter told me that they are at the edge of where the balsa starts in the deck and that the deck is solid glass outboard of the stress cracks. Thus, the deck shows this from a horizontal shot on the aluminum rail.

All over the deck sounds strange. Is your boat a Douglass?

Phil Scheetz
FS 4086

No, this is not a Douglas. And I am baffled by it. The only explanantion I have ont he table so far is that the gelcoat was laid too thick at manufacturing. But I am ignorant--no idea.

It is true that cracks in gelcoat may occur if it is too thick. This is likely to be only cosmetic and not effecting the glass layup of the deck and core. To be sure you could tap the deck with the handle of a screwdriver to see if you get a dull thud. You may also go inside the bow and look up at the underside of the deck. Usually wet or rotten balsa will appear darker than when dry. I doubt you will have any problems.

But does anyone have any idea regarding how the foredeck would develop massive number of hairline cracks if not from the gelcoat being too thick? what else could if be from?


Like the above post suggests, I would call Harry Carpenter at Flying Scot and ask him for possible reasons and corrections. I heard about the thickness of the gel coat, but since it happened all of a sudden, I doubt that the thickness issue caused the hairline cracks.

Post your results. Many of us are curious too. [?]


FS 4957

Hello I am also interested in the reply, and the fix to the problem, as my boat is starting to get a few cracks in the gel coat on the deck. At WRSC we had a boat, since sold, that had a real bad case of the cracks. A mid 1970's boat with all cracks running athwarthship 3 to 4 inches apart on the entire foredeck. These were real gel coat cracks, not crazing. Gabor Karafiath FS 3512

I have contacted Flying Scot, and they have offered no reason as to why. My cracks run perpindicular to centerline and the number is massive and have happened under my watch in the past several years. I have taken good care of the boat, with cover, cleaning etc. No idea why. The only impacts have been banging the dock a bit coming in and my crew standing on the foredeck to tend to the jib, or climbing on board. I was told by a repair shop that age should not have caused this massive cracking even though the boat was built in the mid-eighties. I am ignorant and do not know if this is even true or not.

What type of set up are you using - loose, snug, or tight rig? And, if you are using something other than loose, when did you switch?

bought with and continued with loose rig

Wow, this is strange. [:0]

What did Flying Scot say about the possible threat to structural integrity? Do you have any pictures? Have you inspected the bottom of the deck?

FS 4957

I did some research on gel coat and cracking. For anyone interested, getting many parallel cracks can be from thermal expansion and contraction. The cracks could also come from standing on the deck with the gelcoat brittle from years of weathering. So perhaps the combination did it. Flying Scot Co said they have not had this be a widespread problem, so they do not think it is from the gelcoat being too thick. And the boat is over 25 years old. Any other insights out there in sailor land would be welcomed.

Several years ago I was in the market for a used Scot. A local marina was advertising one that was mid-eighties vintage at a very reasonable price. The reason it was low priced was that the ENTIRE boat had significant gelcoat cracks, and I do mean cracks, not spider web crazing that you associate with banging into a dock, etc. Both the deck and hull had deep cracks running in virtually every direction. Needless to say the dealer had no explanation and a call to FS Co. shed no light as to the cause. Because there were so many cracks in so many areas, in so many directions, I cannot believe physical stress was the root. Nor do I think that temperature gradients would create such severe results. I can only speculate that the actual gelcoat and/or application of same is the real culprit.


The blocks of balsa in the deck are about 2.5" wide and about 4" long laid into the deck like bricks. On my boat, you can see them from under the deck, through the clear glass and resin.

Is there any pattern to the cracks? Do they have any relationship to the layout of the balsa blocks? Have you tapped on the deck to see if you have balsa problems?

Phil Scheetz
FS 4086

I also have a 80's Scot and see small cracks in the gelcoat. These are perpindicular to the centerline both on the deck and the hull. On the deck most are around the mast step and on the hull most are rear of the center board opening. Also some which I chalk up to impact; dock, etc. I am wondering if these are due to flexing of the boat overall and at stress points in particular and also gelcoat fatigue. Can anything be done or does this warrent a complete regelcoating of the boat?

Have you ever thought about sanding off most of the gelcote and fairing the whole boat to paint it with a two part polyurethane type paint?

Joe Brake/Fleet Captain #78

According to a shop I have the boat at, the explanation that seems most plausible at this point is that my crew stands on the foredeck to bring the jib down as we bring the boat in to dock. We also leave the boat by stepping onto the foredeck. Likely, the previous owners had not done that. So the combination of age, the thickness of the gelcoat, and my crew standing on the foredeck to bring the jib down, in recent years, likely caused the damage.

I was advised to wax the deck to fill in and protect the balsa underneath. I do not want to go to the expense of refinishing at this point. Waxing however runs the risk of slipping. So any other feedback or advice is welcomed.

If the cracks are limited to the gelcoat (most likely) it really is a cosmetic issue only. If the cracks are in both; gelcoat and the layer of glass (unlikely) it should be repaired to prevent water intrusion into the balsa. Sounding the deck and visually inspecting it from below should confirm if the cracks are limited to the gel only.

If it is found that the balsa is wet, applying wax will not help, it would need a proper repair.

One last thing I would check is that the wooden stanchion is still positively attached to the underside of the deck and to the trunk at its base.


I do understand that a small boat will get stress cracks, but I have been advised by others who do this for a living that the massive number I now have on the foredeck is way beyond normal, and likely due to what I have already explained--gelcoat too thick and the crew standing on the foredeck. I was told that a small number of cracks is expected at stree points, but not like this.

At any rate, thanks to all for the feedback--it has been helpful.

My hull #287 "Yellow Submarine" also has hairline cracks throughout the deck surface area. [:0]I did see a video from one of the paint suppliers showing how to prepare the surface for recoating with a resin. I wish I saved it, this fall I plan to paint my entire hull with a 2 part roller applied self level-paint.
For now I want to enjoy the rest of the sailing season.
I havn't even figured out how to flip the boat and put it back on my trailer upside down for painting.. [8]I don't want to damage the hull but I don't want to paint upside down either..[?]