Cruisers Yacht hull delamination advice appreciated

[leftbrainstuff]

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.

That's not good advice for a stuctural element like a hull that is subject to bending and torsional stresses and deflections.

You will not achieve a suitable bond. Sounds like the advice of a salesperson and not an engineer.

A viscosity of 'ketchup' is the first give away.

I assume this is a cored vessel. Even if you fill the voids the remainder of the core will grind itself away.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Cadence]

I'm glad the OP said project boat. Sounds like a great testimonial to avoid a cored hull, especially below the water line.

[Three Sisters]

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.

I like your title "advice appreciated".

If your boat is outdrive equipped it may be a good time to remove both of them to survey the surrounding transom core, also every thru-hull to supplement the findings of the moisture meter. Any hardware screwed down onto the inner hull skin such as bilge pumps could also be suspect.

Have you located any cracks along the tabbing for stringers ? What about the weep holes along the bilge, all holes sealed ?

Yes, pictures please.

Hoping the core is indeed dry !

[boatpoker]

Originally Posted by mealsonreels

I don't put much importance in the number itself but give more weight to how the readings relate to each other.

Agree but back it up with percussive soundings as moisture meters can make mistakes and do not always tell the whole story,

[mealsonreels]

Correct. That's exactly what we did. The percussive soundings showed separation but didn't sound like the dull thud of wet or rotten core. Moisture meter around the affected area backed up these findings. There's a good portion, well over 50% of the hull that is lower than 10% moisture and solid, normal percussive soundings.

[UNCIVILIZED]

Have any real samples been taken yet? In particular, the type which test the core to skin bonds in both the "good" areas, & the questionable ones. As well as testing the integrity of the core.
Plus, such would allow you to get something of a real picture of what's going on with the core itself.

[Stumble]

Wait, so the problem is so extensive that something like 40-50% of the hull is bad?


In this case there is nothing to save. Have the builder pop a new hull out of the hold and buy it as a blank. Then transfer the equipment over from your donor hull.

[mealsonreels]

No, I'd estimate 25% of the hull below the waterline is affected. I thought the beauty of fiberglass boats were that most issues can be corrected. I'm looking at it as a way for someone who can't afford a $70,000 boat to invest around $20K and lots of sweat equity and have something that's really nice and will last him for years. You don't buy much in that price range. We were looking at mostly 30-35 foot boats from 1988-1994 in that price range. A 2000's Cruisers is definitely a step up.

I'm self employed and have the ability to take off work for the next few months to work on it. I really was just looking for advice on some different methods of performing a safe repair.

Again, I really appreciate those that offered solid advice. I expected to have to dig through a lot of "don't do it's" to get to the answers.

[jeepbluetj]

Would at this stage it not be normal to bust out a hole saw and take a sample from the 'worst' section? I.e. just cut a hole and take a look?

(I am not a fiberglass pro. Just wondering at what stage it becomes "drill a hole")

[Cadence]

I've read everything from cutting out sections of hull to cutting out the interior. Has anyone considered finding the areas, drilling in from the interior and injecting expandable foam? Just a thought. It may be out in left field?

[boatpoker]

Originally Posted by Cadence

I've read everything from cutting out sections of hull to cutting out the interior. Has anyone considered finding the areas, drilling in from the interior and injecting expandable foam? Just a thought. It may be out in left field?

The core (sound and properly bonded) is an integral part of the design strength.
Foam ain't gonna cut it.

[jimbunyard]

If the delamination is not from water, the question becomes what is it from?

Not only that, but say a complete rebonding of the delaminated sections is achieved (not an easy task), what's to keep the original, un-delaminated sections from falling victim to whatever the now-delaminated sections succumbed to previously?

Seems to me the only proper fix would be to strip the outer skin off, put it in the dumpster and laminate a new skin on, provided the core is good.

To kick some numbers around, for a 1/4" thick outer skin 35'x14', say 3 rolls of 1708, 1500.00, 70 gals iso polyester resin 3000.00 and 3000.00 for incidentals/other. So for 8000.00 or so and a bunch of sweat equity, it might make sense, provided there are no big surprises...

I'd be breaking out the drill to check the real condition of the core.

[boatpoker]

2" hole saw finds badly decayed and totally dry balsa. This spot was found by percussive sounding where the meter showed low moisture. Once an area of balsa get wet, anerobic bacteria starts to eat the lignin. Lignin is the stuff that holds the balsa fibers/cells/xylem together. Once all the lignin is gone the moisture moves even more easily and can migrate to a lower area taking the bacteria leaving dry, decayed balsa behind.

[UNCIVILIZED]

Originally Posted by boatpoker

2" hole saw finds badly decayed and totally dry balsa. This spot was found by percussive sounding where the meter showed low moisture. Once an area of balsa get wet, anerobic bacteria starts to eat the lignin. Lignin is the stuff that holds the balsa fibers/cells/xylem together. Once all the lignin is gone the moisture moves even more easily and can migrate to a lower area taking the bacteria leaving dry, decayed balsa behind.

Great piece of info! Thanks for sharing it/educating us.

[boatpoker]

I have so much stuff on my website that I forgot all about this one ...
Balsa Core = Compost