Gelcoat crazing or delamination?

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CarolineSE

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Hi everyone, first time on ybw forum, first time yacht owner..

Problem.. noticed vertical cracks all over the hull. She is standing on land and the cracks are most prominent on the side facing south (exposed to higher temperature and UV, I’m thinking)

Previous owners had her repainted Dark green, professionally, with a two pack paint from akzo nobel. That was about three years ago i think. I dont know if it s epoxy or polyurethane.

I find the cracks or crazing alarmingly deep in some places and hoping it is not a case of delamination!

Can someone kindly shed light over this? Trying to attach photos...

I’m planning to test damp levels and dremmel the cracks to see whats going on underneath.

If it is a case of gelcoat crazing what do you recomend to use as a filler?
International’s watertite epoxy filler?

I see that many are using epoxy resin filler. My boat is from 1970 and made with polyester resin.
Why is predominantly epoxy used and not polyester gelcoat filler? Does anyone know?

Thank you in advance ?
 
I had what sounds like a similar problem on a similar age boat. It turned out to be overthick gel coat on a dry layup. I also thought the problem was exacerbated by being very dark blue which got very hot even when the air temperature was very cold. Lighter areas of the hull were unaffected. Because the gel coat was overthick in some cases 2 to 3 mm the cracks also appeared alarmingly deep. Dremeling out and filling the cracks with either epoxy or polyester filler (I tried both) did not work for two reasons. One the filler shrinks slightly so it's extremely difficult to hide the crack. Secondly it just cracks again due to differential expansion in the sun. The repair method which worked was rather brutal. I ground out the cracks with an angle grinder tapering the edges over a width of about 50mm then repaired using woven glass tape and epoxy resin. Maybe 8 layers or so. Finally sanding and surfacing with an easy to use and sand car body polyester resin. It actually turned out easier to get a good surface finish than filling narrow cracks. This seems to be lasting well but I did not change the dark colour. That's the next job on the list. This is my experience with my boat it may not be the same problem but I hope it helps you come up with a satisfactory solution.
 
Welcome to the forum and congratulation with becoming a yacht owner.

Cracks comes from excessive stress. This can be internal stress from shrinkage, or from external forces. Sometimes there is a clear clue in the crack pattern and where they are found. I'm not sure what vertical cracks all over the hull says. I can tell about two cases.
One such boat with a lot of cracks was actually the mould plug - the first male hull that the female mould is build upon. It was strongly built, but it had a ton of fairing compound (literally). If I remember correctly most of the cracks was vertical. Could it be that your hull too is actually a plug?
In the other case, the topsides were stiffened with vertical plywood stiffeners. To each side of the stiffeners was several vertical cracks, quite straight close to the stiffener and curved further away. The likely reason for these cracks was deformation of the topside from fenders placed somewhere between the stiffeners.
Are your vertical cracks just straight or slightly curved? Are they uniformly distributed or grouped close to internal stiffeners?
Pictures will help a lot.
 
Welcome to the forums!

More detail needed - boat make, boat model, location, pictures ideally. Was the boat standing on land facing south for some considerable time? Did you have a survey before buying? If so, what did the surveyor say?

Re epoxy vs polyester, it's generally considered that epoxy has better adhesion.
 
Thank you for sharing your experience and methods! It always got to be something! It sounds very similar. I guess also the paint adds a lot to thickness. I hope yours turn out ok! Will you choose a pale color once you paint it?
 
Eilerts and pvb thank you for replying!
The cracks are vertical but a little meandering not dead straight.
It s a Havsfidra built in sweden, about mid production so i dont think it would be the actual mould.
I know it s relatively earlyfor fibreglass and some of them might have had problems with airpockets.

Didnt have her surveyed before buying her 1 1/2 year ago. Previous owners had just been two families since 1970 and they had spent a lot of effort love and money on her.

Pvb, yea..as the boat is in sweden and i in uk, i didnt get around to get her in water until july last year..
So epoxy would stick even better than polyester then, and a better choice?
 
Have a look at the distribution of the problem and if there are any bulkheads behind that area. In the case I described above the cracking appeared in random places. Some were in very solid areas where there were no stress raisers or flexing. The areas affected were more likely to having an excess thickness of gel coat during lay up. The problem got worse during winter storage when temperature differentials were higher. If the cracks shown in the picture are only where there are bulkheads or internal structure then there may be another cause. Worth having a look at how the bulkheads are bonded to the hull.
 
This unfortunately looks like rather more than just fine gelcoat stress cracks, which are fairly common, especially vertically near bulkheads. Again - how old is the boat and what model?

Doesn't look like direct impact damage but could be "hull squeezed" between pier or heavier boats. Or has the boat fallen over on one side - bear in mind that the side away from the immediate impact often gets significantly damaged by the hull flexing. Given these photos I'm afraid there is something significant wrong here. My recommendation would be to get two different surveyors separately to look at it. Pay for an hour of each's time and verbal comments as to what they think it is and what to do.
 
Hi KAM
sounds very similar to yours cracks generally evenly distributed

Jwilson,
perhaps it was squeezed from lifted out of the water? Its a ”Havsfidra” from 1970. Yes.. i better have surveyors to look at it.

Joker,
thats really unfortunate for you. How did it go? Did you repair?

Interesting to read your answers and thoughts, thank you for taking time to answer!
 
CarolineSE said:
Hi KAM
.....

Jwilson,
perhaps it was squeezed from lifted out of the water? Its a ”Havsfidra” from 1970. Yes.. i better have surveyors to look at it.

.....!
Click to expand...

Do you have any evidence of when these first appeared? Lifting a boat using inappropriate gear certainly can significantly squeeze the hull - when we asked the yard to lift our previous boat, they refused on the grounds that they did not have a wide enough rig and there was a serious risk of cracking the hull. Do you have any contact near the boat yard that could do a bit of spying for you? You don't want to talk directly to the management at this stage - would give them an opportunity to hide any evidence. It would be interesting to get pictures of the crane and cradle that were used to lift it.
 
How recently was the boat painted? In an exchange of emails with Caroline we established that it's a substantial solid laminate, and the cracking is all over the topsides (whether it carries on under the antifoul isn't known), so not likely to be crush or impact damage.

My bet is that it's recent paintjob over a filler primer that's post curing and exacerbated by sunlight as noted. Much more likely than 1970's gelcoat suddenly deciding that it's had enough. Seem reasonable?
 
The broken reflexions puzzled me, too. It really looks like the curvature of the topsides is broken up in flat angled panels. I cannot imagine that this comes from the fiberglass. I would rather think that a wrong fairing compound is used, and this is letting go of the paint or loosening from the gelcoat... just a guess.

Try to tap with a small screwdriver, bolt or pencil horizontally towards a crack. Is there any change in the sound?
 
Toffee apple.

I suspect the fault would be with the paint job at some point, be it fairing compound (as eilerts suggests) coming away from the gel or the paint coming away from the fairing, or the gel if it didn't need fairing.

Perhaps applied too thick for the cure, or incorrect component mixture, or even a compatibility issue. Perhaps all of the above.

So much to go wrong if the prep isn't 100%

Try the tapping for sound, but really you need to take a small section off to see what's going on.

Tony
 
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It was painted 2015.

Yes paint and chemicals can be quite fussy!

I know that previous owners was covering her with a real thick and big tarpaulin, i used a lighter and smaller ones for the top mainly, leaving the sides of the hull exposed while out of the water (the season is shorter in sweden) Perhaps this is why it didnt start cracking earlier..

I didnt hear difference when i tapped last time. Will have a go when over there and take a section off.. might have aomeone to come and look at it
 
The fact that the boat was in Sweden could be significant. My problem became really apparent after winter 2010 in Scotland. It had been down well below -10C for several days. When I visited the boat there was ice on deck and everything was frozen but the sun was out and the dark painted areas were warm to touch. I think the stresses caused by differential expansion must have been very high and the damage became apparent over the next 6 months or so. Repair was carried out a year or so later and have been successful. Fortunately we haven't had such prolonged cold weather since. I still have the dark painted areas but am contemplating a lighter colour on repaint. There don't seem to have been any structural problems.
 
eilerts said:
The broken reflexions puzzled me, too. It really looks like the curvature of the topsides is broken up in flat angled panels. I cannot imagine that this comes from the fiberglass. I would rather think that a wrong fairing compound is used, and this is letting go of the paint or loosening from the gelcoat... just a guess.

Try to tap with a small screwdriver, bolt or pencil horizontally towards a crack. Is there any change in the sound?
Click to expand...

You may be right about a significant amount of fairing compound covering old damage, then painted over, and the fairing compound not being as flexible as the hull and cracking away. Hulls do flex. I still think surveyors eyes on it a good idea.
 
CarolineSE said:
It was painted 2015.

Yes paint and chemicals can be quite fussy!

I know that previous owners was covering her with a real thick and big tarpaulin, i used a lighter and smaller ones for the top mainly, leaving the sides of the hull exposed while out of the water (the season is shorter in sweden) Perhaps this is why it didnt start cracking earlier..

I didnt hear difference when i tapped last time. Will have a go when over there and take a section off.. might have aomeone to come and look at it
Click to expand...

Good plan.

I'd continue to involve the forum over having just one professional opinion mind, collectively we'll come up with the solution and the way forward.
A decent surveyor will no doubt source the problem, but you've got interested viewers to please now.
As per Kam's post, there is probably a relationship between the cold climate and (hopefully) inadequate prep or painting requirements that have caused this and not damage through lifting/stress.

Think it's safe to say there are sections of the paintwork that are beyond salvage, so nipping a small section out along one of the cracks to determine the depth is the first check.

Is it to the depth of the paint, any fairing, the gel coat, or the grp, the deeper you go, the deeper pockets you will need.


Good pictures or videos if possible of the progress will help us to help you, I'd be making anoccasionalyachtsman lots of tea.

Tony
 
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