Can a wet cored hull be replaced?

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palasz

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Jan 19, 2019
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23
Location
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Hello-

My wife and I are looking at 1994 Kadey-Krogen with a cored hull. The coring material is Airex?

IF the hull is wet what are my options? There were only 30 of these yachts manufactured...we only have a dozen on West Coast to choose from.. Wife likes the Whaleback which was made from 1994 to 200? The space is great inside for us.

Can the hull and coring material below the waterline be replaced? Is there anyone in the Anacortes area that I can call to get a rough idea on what this would cost?

Has anyone on this forum had a wet cored hull replaced?

Thanks,

Mike
 
There is no reason to replace the core if it’s wet. The beauty of Airex or pvc as a core material is it doesn’t rot under most conditions. If the core is wet, it can be dried out. You need to first though find out how the moisture got into the core. It’s usually through hull penetrations. A marine surveyor can help determine the extent and also suggest a remedy.
 
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Larry M said:
There is no reason to replace the core if it’s wet. The beauty of Airex or pvc as a core material is it doesn’t rot under most conditions. If the core is wet, it can be dried out. You need to first though find out how the moisture got into the core. It’s usually through hull penetrations. A marine surveyor can help determine the extent and also suggest a remedy.
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How is the core material dried?
 
Larry and I both have cored hull KK42’s (mine is hull 90). I don’t lay awake at night worrying about whether it has water intrusion.

Jim
 
What Jim said. :thumb:

Maybe do a search here on the Forum? Put in “cored hull” and you’ll get a bunch of hits. Don’t freak out but filter through the weeds. If you’re serious about the boat, pursue the it and get a good surveyor. If Matt Harris is still around, hire him or someone from Marine Consultants Inc., Bellingham.

Please keep us posted on your search.
 
Larry M said:
What Jim said. :thumb:

Maybe do a search here on the Forum? Put in “cored hull” and you’ll get a bunch of hits. Don’t freak out but filter through the weeds. If you’re serious about the boat, pursue the it and get a good surveyor. If Matt Harris is still around, hire him or someone from Marine Consultants Inc., Bellingham.

Please keep us posted on your search.
Click to expand...

Thanks Larry.

I read everything on this forum regarding cored hulls. I just want to make sure a wet hull can be repaired, roughly what it will cost and if there are companies in the PNW that do this work.

My wife and I are moving from East Coast and we have chartered a few big boats and cruised around the San Juans but we do not have any local knowledge on the marine trades around Anacortes and what can be fixed and not fixed. I have seen that boat graveyard on I-5 around Everett? and do not want to make a 500K mistake.
 
There is a company in Michigan called Dryboat that dries out cored hulls. Don’t know what their geographic limits are.
 
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palasz said:
Holy Smoke..thanks for posting...It looks like the space shuttle heat tiles.. So, is the repair with Airex again or can you just go to solid fiberglass at this point.

I wonder what that cost...
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It looks like they put airex or equivalent back in. I am sure it was not cheap.

FYI - Here is an article on dryboat done on a balsa core: https://www.boatingmag.com/dryboat-treatment-for-wet-hull-core?G5EMszXO1w3zO6lT.03

Airex can take water better than balsa i think, so as long as no delamination and no freeze/thaw damage drying out may be all that is needed as some suggest.

Krogens are beautiful boats universally loved by their owners from what I can tell. I think later models went to solid hulls at least below the waterline.
 
Welcome to TF and to the PNW. You’re moving to a boating Mecca with many yards and options for work. Anacortes, Port Townsend, Port Angeles all have highly regarded yards.

It sounds like you’re trying to understand a worst case scenario based on a pre-purchase vessel? I’d recommend contacting the Kadey Krogen folks in South Lake Union for advice and recommendations on preferred yards.

Otherwise, as other have stated, get a good survey.
 
Pacific fiberglass in Seattle is the outfit I’d call for anything serious with fiberglass. I’ve seen them pull off things others would not even attempt. As a rule, I don’t endorse firms anymore, but I’d still recommend these guys. When my boat was damaged, they put it back together, better than new. They wouldn’t even blink at a job like this, and would be the ones to tell you what it would cost to accomplish by the only folks worth doing it. Normally, this kind of endeavor is a poor idea on a boat you are looking to purchase. Find a way to be cold and impartial.
 
ghost said:
Pacific fiberglass in Seattle is the outfit I’d call for anything serious with fiberglass. I’ve seen them pull off things others would not even attempt. As a rule, I don’t endorse firms anymore, but I’d still recommend these guys. When my boat was damaged, they put it back together, better than new. They wouldn’t even blink at a job like this, and would be the ones to tell you what it would cost to accomplish by the only folks worth doing it. Normally, this kind of endeavor is a poor idea on a boat you are looking to purchase. Find a way to be cold and impartial.
Click to expand...

Don't worry...we are patient and persistent....I'll wait for a hull after #7 when they went to solid fiberglass. I'm not afraid of projects as long as there are professionals around to fix issues..
 
I also have a KK with a cored hull. Although there are various methods that yards have used to deal with the wet core issue, there are many out there cruising “with” wet hulls. Of course a dry hull is preferable, but if you’re not in a freezing climate, you may never know the difference. I recently driilled my hull, ground out some major blisters, and let it drain for over 100 days. Never got more than an ounce total out of the entire effort. Another owner drains his hull every time he gets a bottom job and tells me he gets about two gallons, but the boat lives in warm water. Still another owner had his hull pealed and vacuum drained, then deluged daily with alchohol for two weeks. When they glassed it back up, moisture was down below 10% (14% is acceptable). Then there’s Osprey Composites in Maryland who kind of developed the technique for Krogen, regularly doing 42’s and Manatees. I got an estimate for peal, dry and re-glass two years ago for over 20K with a five year guarantee. The point is that if you intent is to make a boat with a wet hull perfect, it may take a major money and time investment. If you want to re-seal the through hulls, drill and wait to dry, it might take less $$ but still a bit of time. If you want to enjoy it as is, you probably can, but all the options should still reflect your possible investment. Buying a Krogen with a wet hull is really no big deal if you buy it right to begin with. Find a surveyor who love his hammer and moisture meter, and make sure you know if it is salt water or fresh water intrusion.
 
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I do not believe the Airex can get "wet" beyond its surface.It is closed cell.

A wet reading on a meter would indicate the laminate is wet , no big deal, or the lamination of the glass is loose and there is water between the Airex and glass.

Before vacuum techniques were perfected there was always a question on the ability of the hill mfg to ensure the Airex was properly bonded with the outer hull laminate.

One technique to try to find out whats up ( besides a core sample) is to use a tuning fork and listen to the hull.

With no core attached the sound will be very different from the rest of the hull.

If the topsides and bottom sound the same , all should be well.
 
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Palasz
Why not buy a vessel that has a non saturated hull to begin with? It would seem that a wet hull that has not been repaired properly already speaks volumes as to other potential problem areas.
 
Simi 60 said:
Bloody contour foam
Voids very rarely get filled during the layup.

I have done repairs before where we drilled a 2 inch hole through the skin, removed, fitted vacuum pumps and sucked out several hundred litres of water over a week.
Foam was fine and still attached
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Several hundred liters from a single 2" hole? impressive..
 
IMO the strength of a cored hull comes from the box structure created by bondind an outer and inner skin with a web created by core. Similar to an I beam. In those PIX the outer skin is loose from the core so there is not the box structure strength.
 
That is why I preffer older boats with no core.
 
palasz said:
Do you know if KK used solid glass around the thru hull fittings? I found this article very informative...
Click to expand...

Our 42 has solid glass at the hull penetrations or at least on the five that we’ve removed (transducers and/or thru-hulls). What I don’t know is if the core was removed before or after the hulls were laid up.
 
Ok.. Lots of great information and feedback.

Are there any trawler makers that have solid fiberglass hulls AND solid superstructure and or decks?

Thanks in advance for replies.
 
If you link my google photo album, I would appreciate if you linked the blog as well to explain what is happening, and give them contact information to answer questions vs. everyone speculating about what they are looking at.
 
I would talk to Tom Button at Kadey Krogen. He’s been around longer than most of the staff there. IIRC, the later models of KK42’s were solid below the water line but I don’t have information on the hull number when that changes. Tom would know.

http://www.kadeykrogen.com/our-story/staff/
 
palasz said:
Ok.. Lots of great information and feedback.

Are there any trawler makers that have solid fiberglass hulls AND solid superstructure and or decks?

Thanks in advance for replies.
Click to expand...

I wouldn't worry about the cored superstructure and decks. A large percentage of the members of this forum have them. ?
 
It`s significant imo that KK went from cored to solid below the waterline.
I explored this issue in relation to a Beneteau,all of which are balsa cored below the waterline. I decided that cored above, and cored superstructure, were fine, but cored below is a :nonono: no:nonono: no. At a minimum, every skin fitting comprises a risk.
 
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