Cruisers Yacht hull delamination advice appreciated

[Moon rise]

Hi ya,
Had the similar problem with the Morgan 45 I bought, on first inspection the hull looked good but once I started picking the problem got big and then bigger and bigger to the point we I remove the complete underwater hull down about 4 mm, it came off in sheets with a crowbar. The hull was then filled and sanded, then 3 layers of fiberglass put back. luckily I was in the Philippines where labour is relatively cheap and the yard had some idea what to do. hole job was about 4k GBP

[minaret]

Originally Posted by boatpoker

Unfortunately this is not uncommon on Cruisers. One I inspected last year had severe core decay from bow to stern. Repair was estimated at $80k to remove bottom skin and old core then re-glass the bottom. I was called in when a contractor hired to install a bow thruster found the core so rotten he could not secure the tube. Cruisers often installed throughulls right through the balsa and sealed them with what I am pretty sure is just silicone ..... not good.

I was involved with another cruisers that sank when the throughull fell out, yes ! fell out. Again installed with silicone. Photo of that throughull below.

Yes, this. Last Cruisers I did had severe and extensive core rot. Sure it's not wet? Moisture meter readings are?

[UNCIVILIZED]

A guy (surveyor) who's certified with a Thermal Imager can tell you a lot about the state of things as well. And if you do a search for such on here, or as a last resort, a post requesting info & assistance on said topic. Then you should be able to find a good bit of info as to what they can discern, complete with pics.

Ditto via some standard online searches. And there are even NDT (Non-Destructive Testing) forums, which will cover a multitude of related topics to this. As well as, of course, websites & companies which specialize in such "magic" tricks & info discernment.

Though, like many others, my concern (aside from a wet, & thus, dead core), is why did such massive delamination take place? And what's the plan to prevent such in the future, if it makes sense to salvage her.

Plus, & assuming that her core's been wet, I can't see how it would make any sense to try & bond skins onto a core which has such a history. Especially as it's likely contaminated to some degree by water intrusion. Thus rendering it non-viable for bonding.

[mealsonreels]

Moisture readings overall are 6-8%. These are over the Some isolated areas are 14-16% I assume in those areas the core will need to be dried or replaced if needed. I think replacing large sections of core would be a deal breaker but isolated sections should be a tolerable job.

[minaret]

Originally Posted by mealsonreels

Moisture readings overall are 6-8%. These are over the Some isolated areas are 14-16% I assume in those areas the core will need to be dried or replaced if needed. I think replacing large sections of core would be a deal breaker but isolated sections should be a tolerable job.

That's quite dry. Meter model?

[mealsonreels]

I don't have that info. Professional surveyor , it was yellow, I think he said it was about $600. I watched him check the calibration before the survey. He didn't seem too concerned about the 16% readings either but I assume it's too wet for epoxy to properly adhere to?

[minaret]

Originally Posted by mealsonreels

I don't have that info. Professional surveyor , it was yellow, I think he said it was about $600. I watched him check the calibration before the survey. He didn't seem too concerned about the 16% readings either but I assume it's too wet for epoxy to properly adhere to?

A Tramex. Good meter. 16% is borderline, damp core, not wet. This may be the rare case where injection may actually work. I would carefully map out moisture meter readings before considering it though.


Perhaps some research on this forum for injection methods is warranted. A grease gun with zerk fittings is a good start.

[mealsonreels]

I contacted West Systems tech line. They said the same thing that injection may work. They suggested ketchup consistency and a warm shop.
I think it would be prudent to try it on one section to see if it "sticks". Then proceed to the rest of the boat.

[minaret]

Originally Posted by mealsonreels

I contacted West Systems tech line. They said the same thing that injection may work. They suggested ketchup consistency and a warm shop.
I think it would be prudent to try it on one section to see if it "sticks". Then proceed to the rest of the boat.

Oh, it'll stick. The question is, for how long. If the core is damp enough, it may well eventually rot. Maybe take some pics and post them. Mark out areas of delam with chalk first. Make sure you personally hammer sound. Mark out moisture meter readings too.

[boatpoker]

Moisture meters CANNOT give a percentage of moisture in core through glass.
All readings are relative and you have no idea how that meter was calibrated (if calibrated). If the core has completely disbonded from the laminate the meter will show low or no moisture as the moisture must be in contact with the skin for the meter to read it. Suggest you take a look at Moisture Meter Mythology.

[minaret]

Originally Posted by boatpoker

Moisture meters CANNOT give a percentage of moisture in core through glass.
All readings are relative and you have no idea how that meter was calibrated (if calibrated). If the core has completely disbonded from the laminate the meter will show low or no moisture as the moisture must be in contact with the skin for the meter to read it. Suggest you take a look at Moisture Meter Mythology.

Dude, in this case you just take the reading from inside. It's not rocket science. As all readings are indeed relative, and in this case most of the boat reads dry, wet readings should most certainly be accurate and indicative of moisture. I have mapped out square miles of wet core with a meter, have never been wrong yet. When I peel the top skin the wet core always perfectly matches my map. Pretty far from cannot give a percentage!

[mealsonreels]

I agree. We could clearly see the different readings in different areas. I don't put much importance in the number itself but give more weight to how the readings relate to each other.

[minaret]

Originally Posted by mealsonreels

I agree. We could clearly see the different readings in different areas. I don't put much importance in the number itself but give more weight to how the readings relate to each other.

As you should.

[boatpoker]

Originally Posted by minaret

Dude, in this case you just take the reading from inside. It's not rocket science. As all readings are indeed relative, and in this case most of the boat reads dry, wet readings should most certainly be accurate and indicative of moisture. I have mapped out square miles of wet core with a meter, have never been wrong yet. When I peel the top skin the wet core always perfectly matches my map. Pretty far from cannot give a percentage!

Dude ??? you're kidding right ?

First you agree that readings are relative then you say "Pretty far from cannot give a percentage" ??????

Not sure if you are familiar with that Cruisers model but there is extremely limited access to the interior hull out side of the engine compartment. If the core has suffered from serious decay and has turned to dust, moisture levels will still read low like this one ......

[leftbrainstuff]

Originally Posted by mealsonreels

Hello,
I bought a 2002 Cruisers 3572 as a project boat. The boat is in great shape, but for whatever reason there are large sections of the hull where the outer glass skin is separated from the core. These areas start about 5 feet back from the front and continue back to just in front of the engine room.
I've been advised of a couple different methods of repair. Some say to drill holes and inject resin to fill the voids, then anchor the repair with screws until the resin cures.
Others say to skin the areas in sections, inspect the core, and glass the sections back on. All the delam is below the waterline so it's all covered by paint.
I'm favoring the second method of taking off 3 foot wide sections of the hull from the waterline to the bottom, making sure the core is ok, and re glassing the sections back on with thickened epoxy. A vacuum bag or screws would be used to hold the section in place.

Has anyone done a project like this? Any advice would be appreciated regarding how to cut the sections, split the parts of the skin from the core that are still attached, and how to anchor the piece while it's curing.


I've had a fair amount of experience with doing fiberglass work on boats. Also, the boat is inside my shop with a controlled environment.

Thank you

You'll need to remove the delaminated sections replace the core and rebuild. A very big job.

Filling with epoxy will not effect a structural bond. Vacuuming bagging will not be effective over the old skin. Screws through the hull are not what I would consider appropriate on a hull repair.

Depending on how much you cut out you'll need to ensure the hull is well supported. It sounds like the delamination is 10 to 20 feet long?

From what you've described (no pics) it might be easier to scrap the hull, buy a sister ship and make one good boat from two.

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