Cracked cabin roof, non-starter?

Tylo

Member
195
111
Sweden
Hi,

Bit of a noob question here but hopefully someone can find the time to voice their opinion on this.

With the current limitations (both government and self-imposed) on travel and sailing abroad I've been eyeing up some nice daysailers and came across one that was very enticing in terms of sailing performance. I went to look at it today and found a very nasty looking bilge (and if anyone can tell me what the cracked goo around that keel bolt is, that'd be neat).
As I turned my gaze upwards I saw that the roof had a big crack along the aft bolts of the compression post. The current owner is no help as he bought the boat a year ago and has sailed it once since. He also seems to know next to nothing about it.

Clearly water is getting in somewhere (although not in huge quantities, there's no auto bilge pump and as I said the owner is never on the boat) and I feel like the deck must have been flexing quite a bit for this crack to form.

Is it fair to assume the entire deck is water-logged and requires extensive repair, or could this be fixed by something as simple as grinding away some material in and around the crack, filling it with epoxy and glassing over?

The boat is 29 feet long and that crack is maybe 20-30 cm (8-12 inches) long.

Thank you guys in advance for your time.

IMG_6031.JPG IMG_6032.JPG

 
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PaulK

Super Anarchist
As you suggest, there is obviously something going on with the cabin overhead.  You will need to sound the area around the mast: Tap it with a plastic hammer or the handle of a big screwdriver and listen for different tones. "Ding" is good; it indicates things are still stuck together.  "Thunk" is not - it means that the deck has delaminated in that spot. How big the "thunk" area is will tell you how much needs to be fixed.  To avoid having to re-do nonskid in the deck this sort of problem is often fixed from the inside, where it won't show as much. 

In the bilge... what is it?  It does look quite funky.  It could be the remains of antifreeze that was used to keep any bilge water from damaging the hull over the winter.  Look around for more cracks, especially in the way of the tabbing - where structural members like ribs or stringers are fiberglassed to the hull. You might learn more from sounding this area as well.  

 

Tylo

Member
195
111
Sweden
Thank you PaulK!
I was knocking around on the decks around fasteners and such (with my knuckles, mind you) and thought it sounded different all over the place - mostly thunks I thought.
I guess I haven't developed the "ear" for it maybe.

I'm going to go look at another boat of the same model.
It's not for sale but perhaps having a look and a feel at/of it can tell me something about the structure of the one I intended to purchase.

 

Tylo

Member
195
111
Sweden
Sound advice. The problem is only 3 or 4 of these were built before the designer/builder passed away.

The other problem is it's a 4000 lbs boat, 1700 lbs of which is ballast and it has 430 sq ft of working sail area. Add to that a weekender-able interior and there aren't many other models that could replace it, at least not within budget. But maybe this crack actually puts this boat out of budget...

 

PaulK

Super Anarchist
Sound advice. The problem is only 3 or 4 of these were built before the designer/builder passed away.

The other problem is it's a 4000 lbs boat, 1700 lbs of which is ballast and it has 430 sq ft of working sail area. Add to that a weekender-able interior and there aren't many other models that could replace it, at least not within budget. But maybe this crack actually puts this boat out of budget...
If you have the time, materials for fixing the overhead should not be overly expensive. This depends, of course, on how extensive the delamination is, but even an area 1m x 50cm might cost less than 200 Euros if you  fix it yourself. Once opened up, cleaned, and dried out, it might only take a weekend.       If there are other issues... it could be different. 

 

12 metre

Super Anarchist
3,944
739
English Bay
Thank you PaulK!
I was knocking around on the decks around fasteners and such (with my knuckles, mind you) and thought it sounded different all over the place - mostly thunks I thought.
I guess I haven't developed the "ear" for it maybe.
Knuckles probably better than nothing, but the edge of coins work reasonably well in a pinch - the bigger the better.

As for the sound, it's hard to differentiate until you have actually heard the unmistakable thunk of delaminated glass.  The sound is just so completely different that unless you hear that thunk while tapping out, I would assume it is fine even if the sound is not uniform .

That's not to say the core is not rotten - just that it has not delaminated and the core is still doing it's job for the most part.  Unless balsa core has turned to soup even rotted balsa has strength.  But if it has turned to soup, it has effectively delaminated so you will probably hear that thunk sound.

 
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Tylo

Member
195
111
Sweden
Alright, situation update.

I've been on board the sister ship now and it felt pretty much identical in terms of a slight flex in the deck when walking on the big open areas of it.
The laminate just isn't very thick I guess. 4000 lbs at 29 ft should have told me that from the start.

As for the crack the owner of the sister ship reckoned it would be fine to just grind/sand it out at a very shallow angle, fill the crack with epoxy and glass over it. He said rather than worrying about the crack as it is, I should investigate why it appeared in the first place which makes sense. By the looks of things the laminate has been pulled apart so maybe someone got a bit too zealous with the running backstays...?

If you have the time, materials for fixing the overhead should not be overly expensive. This depends, of course, on how extensive the delamination is, but even an area 1m x 50cm might cost less than 200 Euros if you  fix it yourself. Once opened up, cleaned, and dried out, it might only take a weekend.       If there are other issues... it could be different. 
Thanks again for the input. If it's as simple as I'm hoping to fix I'll definitely manage it myself. We're rapidly approaching colder temperatures here in Sweden and we typically keep our boats on the hard during the winter months, so the boat will be out of the water soon no matter what. I'll have plenty of time to work on it then. If it turns out that the crack is an easy fix I'll probably go buy the boat next weekend.

Knuckles probably better than nothing, but the edge of coins work reasonably well in a pinch - the bigger the better.

As for the sound, it's hard to differentiate until you have actually heard the unmistakable thunk of delaminated glass.  The sound is just so completely different that unless you hear that thunk while tapping out, I would assume it is fine even if the sound is not uniform .

That's not to say the core is not rotten - just that it has not delaminated and the core is still doing it's job for the most part.  Unless balsa core has turned to soup even rotted balsa has strength.  But if it has turned to soup, it has effectively delaminated so you will probably hear that thunk sound.
Thanks for the input! I'll try and bring something better than knuckles next weekend if I go back to it. I'm glad to hear the sound doesn't have to be completely uniform though.

The boat is completely cored with divinycell except below the waterline and where the jammers/winches attach where it's solid glass. If this were a balsa boat with this kind of damage I probably wouldn't have even considered taking on such a project. 

 

PaulK

Super Anarchist
Alright, situation update.

The boat is completely cored with divinycell except below the waterline and where the jammers/winches attach where it's solid glass. If this were a balsa boat with this kind of damage I probably wouldn't have even considered taking on such a project. 
Actually, because the grain in balsa runs at 90º to the laminate and soaks up water, it tends to wick less and spread delamination less than foam core does. The foam doesn't absorb water, so if  25cc's leak into the core, it spreads all over the place and when it freezes: delanimation all over the place. If 25cc's leak into balsa core, a good bit of it is absorbed by the wood, so there is less delamination when it freezes.  

 

12 metre

Super Anarchist
3,944
739
English Bay
Actually, because the grain in balsa runs at 90º to the laminate and soaks up water, it tends to wick less and spread delamination less than foam core does. The foam doesn't absorb water, so if  25cc's leak into the core, it spreads all over the place and when it freezes: delanimation all over the place. If 25cc's leak into balsa core, a good bit of it is absorbed by the wood, so there is less delamination when it freezes.  
Yes,  balsa remains bonded pretty tenaciously unless it has turned to soup.

Foam has more of a tendency to delaminate which is why core bond or some similar product is used on polyester boats.  Even then it needs to be applied properly. 

I live in an area that seldom gets below freezing especially near the ocean and the foam core deck on my old boat was delaminated in  about a 2x6ft area and the core bond was applied somewhat spottily IMO.  Most of the deck was wet as far as I could tell although not delaminated.  The foam was Klegecell.  I took a bunch of the cut out cubes home and even after 6 months of drying out I could still squeeze water out of the cubes.  So even though the term "closed cell foam" implies it is impermeable to water, Klegecell at least would absorb water.  However I doubt being wet in itself has any impact on it's mechanical properties like it would with balsa.  Delam is the killer for foam cores.

One last thing, if you think you've identified an area of delam and if it is the outer skin that is delaminated, you will feel movement if you press down on it with your hand since you are basically down to one thin skin which has very little stiffness.

 
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Bruno

Super Anarchist
3,958
136
Your photos are somewhat obscured, the bilge looks like maybe dried salt or something, looks like there's been a lot of water draining throught here with all the rust etc.

But if you're set on buying the boat you might want to consider just overbuilding that area, never mind a few extra kilos. That transverse cracking, all that leaking, the throughbolts along the crack, mention of highly loaded rig etc makes me inclined to suggest just cut it open until the cracks stop, glue in a suitable piece of plywood, glass it solidly, and go sailing. Essentially you're saying the cabintop in folding across the compression post which would mean it's not stiff enough.

Working from above is easier and faster, build a form in place below, mask it well, confine all the mess to ondeck, kiwigrip that area and it could be a long weekend job if it's dry and clean already. Formica can be a quick form supported by a couple of contoured ribs, hot glued, wedged or held up with bent sticks or battens.

 
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Tylo

Member
195
111
Sweden
Your photos are somewhat obscured, the bilge looks like maybe dried salt or something, looks like there's been a lot of water draining throught here with all the rust etc.

But if you're set on buying the boat you might want to consider just overbuilding that area, never mind a few extra kilos. That transverse cracking, all that leaking, the throughbolts along the crack, mention of highly loaded rig etc makes me inclined to suggest just cut it open until the cracks stop, glue in a suitable piece of plywood, glass it solidly, and go sailing. Essentially you're saying the cabintop in folding across the compression post which would mean it's not stiff enough.

Working from above is easier and faster, build a form in place below, mask it well, confine all the mess to ondeck, kiwigrip that area and it could be a long weekend job if it's dry and clean already. Formica can be a quick form supported by a couple of contoured ribs, hot glued, wedged or held up with bent sticks or battens.
Yeah, sorry about the photo quality. There was approx. 3-4 liters of water in the bilge, not much considering there is no automatic bilge pump and the owner hasn't used the boat all year. The "cracked" stuff around the keel bolt is submerged. I'm beginning to think it has to be some kind of galvanic reaction going on between the keel bolt/nut and the metal plate (aluminium?) underneath it. Not great.

I think I will do as you suggest. Some of my colleagues have suggested the same thing; cutting it open, reinforcing it and glassing over again. The few extra kilos don't bother me more than the deck flexing to the point of cracking.

Just curious. What kind of boat?
It's an "Eloge 29", built sometime in the mid 90's I think. Unfortunately the designer passed away in 2006 and from what I can tell there were only 3 or 4 of these 29 footers built. He also designed a 38 footer which was more popular though. This 29 footer has no facilities like head, galley or refrigeration etc at all so you could see how maybe only racers or serious daysailors would buy this.

That's not promising.

 

Movable Ballast

Anarchist
6,201
249
San Diego
Hi,

Bit of a noob question here but hopefully someone can find the time to voice their opinion on this.

With the current limitations (both government and self-imposed) on travel and sailing abroad I've been eyeing up some nice daysailers and came across one that was very enticing in terms of sailing performance. I went to look at it today and found a very nasty looking bilge (and if anyone can tell me what the cracked goo around that keel bolt is, that'd be neat).
As I turned my gaze upwards I saw that the roof had a big crack along the aft bolts of the compression post. The current owner is no help as he bought the boat a year ago and has sailed it once since. He also seems to know next to nothing about it.

Clearly water is getting in somewhere (although not in huge quantities, there's no auto bilge pump and as I said the owner is never on the boat) and I feel like the deck must have been flexing quite a bit for this crack to form.

Is it fair to assume the entire deck is water-logged and requires extensive repair, or could this be fixed by something as simple as grinding away some material in and around the crack, filling it with epoxy and glassing over?

The boat is 29 feet long and that crack is maybe 20-30 cm (8-12 inches) long.

Thank you guys in advance for your time.

View attachment 386591 View attachment 386592
Looks like expansion of the core material from all the water coming in through those rusty holes and around the compression post. Take out the post and cut the inner skin away till you get to good core material. Replace the core or better yet use a non-absorbent material (closed cell foam) Glass it back in, paint and go. Had to do a similar fix around the chain plate to my boat. Not that hard to do. 

 
Looks like you may be going... underneath that nearby bulkhead to chase down the extent of the rotten core. At which point I suppose you’d be better off attacking from above and reinforcing heavily from below to deal with the crack.  Wonder if freeze-thaw cycles contributed to the cracking. Don’t like the look of those bolts. 

 

jamhass

Anarchist
783
131
Get a surveyor and an estimate for proper repairs from a competent boatyard.  Use this info to negotiate price if you are still interested.  Might save you $$$ in the long run.

 

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