Cruisers Yacht hull delamination advice appreciated

[mealsonreels]

Hello,
I bought a 2002 Cruisers yacht 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. It's about 30% of the hull total.

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

[a64pilot]

Been done lots, I want comment as I don't have the knowledge base, but there are others here that do.
Minaret?


Sent from my iPad Pro using Cruisers Sailing Forum

[Stumble]

Do you have any pictures?

[mealsonreels]

I haven't got pics yet. I haven't started the work yet. Right now, it looks like a normal boat. On a survey, the percussive soundings showed the delam. That's how the owner found out about it.

[ozsailer]

Hello M on M. I think I can add some info on this as my wife and I went through this process with our old mono, a Cheiftain 38 called "Southerly Miss". In short we had owned the boat for several years before it was found that it had severe delimitation. Long story short the hull was cored and to effect the repair to a seaworthy repair the glass to the core was required to be stripped and replaced. The boat was out of the water for 10 months but was reparied better than new. Rather than type the whole story here, if you are interested I have done a report on another site called Trailer Sailer Place ( I used to own and sail trailer yachts) There is a sub forum called the Dark Siders. Go into the forum and in the search section and seach for "A cautionary tale" My tag is ozsailer. It has lots of photos and is well detailed on what occurred. I am sure it will answer a lot of your questions.


Greg and Sue
SV Sunshine

[barnakiel]

I have seen similar repair done in the boatyard that is prepping Rich Wilson's boat.

However, they show how they do it on a hull where delam was limited to smaller areas. You are talking about very large patches.

Maybe, time allowing, you could post here how you are handling this challenge?

b.

[mealsonreels]

Thanks Ozsailer, looks like a lot of information. I'm hoping to use the same skins that came off, assuming I can get them off in decent shape.

[Stumble]

As I understand it it's basically the same job as replacing rotten balsa core. Maybe Minaret will chime in but basically you have to cut it open, replace the likely damaged core and then reattach the removed skin.

[Cadence]

I hope Marinet does chime in. I am afraid you may not like his reply. I don't want to be the barer of bad tidings. Putting the shell back on an egg?

[skipmac]

No matter what happens you have a really big job facing you. Most likely many, many hours of labor and some significant money in glass, resin and more.

Before any repairs I recommend you think carefully and decide if the boat is really worth the time and money. Part of this decision would be determined by how much your time is worth and what the boat will be worth when you're done. If it's going to need engines as well as major hull work then I might consider it a right off. If you have a job that pays x$/hour and the hours you spend fixing the boat benefit you half that much then it's again a losing proposition.

If you're determined to go ahead then first step is to look at the delamination in detail. What caused it to delaminate, what is the core made of, what shape is the core in?

If the delamination is just because there was a poor bond between the skin and the core it might not be too bad. If the core is compromised: wet, rotted balsa or foam core that has turned to powder then you're looking at a much bigger job.

This may sound like a joke but I've been there and done that several times and there's more truth to this than you might think. Any major boat repair will end up costing twice as much and take twice as long as you originally estimated. I'm just finishing a 2-3 year boat project.... 6 years later.

[Three Sisters]

Otoh,

gutting the interior to gain access and doing it from the inside is the approach I'd take. The outer skin blocked fair to the rest of the hull and left intact. There's no way I'd cut this open midships and rely on bottom paint covering it all up. A repair from the outside says nothing of the internal stringer system and it's structural integrity, covered by molded in furniture. Considerering these points, I'd also look at a repair from the inside.

Not what the OP is looking at but an alternate choice.

[mealsonreels]

The sales price of the boat was at a significant discount. The motors are less than 400 hrs each. The rest of the boat checked out OK.
We thought about going at it from the inside but since the core is dry and intact , that would be a lot more work than skinning the outside, I think.
I appreciate the advice so far

[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.

[skipmac]

Originally Posted by mealsonreels

since the core is dry and intact , that would be a lot more work than skinning the outside, I think.
I appreciate the advice so far

You're sure the core is dry and not rotted? Is is still attached to the inside skin?

Any idea why the outer skin has separated? Seems unlikely that is just came apart without some significant contributing factor. It could have been poorly bonded to start but I think much more likely it was due to a wet core. That could be a big factor in the process.

[Cadence]

God bless you. I hope it works out.