HUNTER 456 (2002) - PROBLEMS WITH HULL GLASS FIBRE DELAMINATING

[a64pilot]

You Vacuum the moisture out of an airconditiong system. The way it works is of course the lower the air pressure, the lower the boiling point of water. A hard vacuum will make it so the water boils off at room temperature.
Assuming you can pull a hard vacuum and it not hurt anything, it should work?

[toddedger]

[quote name="toddedger" post=2326280]I used existing holes in some spots. Some places i drilled a hole from bottom, and some spots i had to drill in the deck. You don't need a very big hole to suck through, 1/8 " will work.[/QUOTE]<br />
<br />
That's an interesting approach. I'd always wondered how one would get the water out if it's end grain- your heat/vacuum trick would do it.<br />
<br />
1/8" shocked me though. All the boats I'd seen this done on had at least 1/2" holes. Interesting. I suppose that 1/8" would be just fine.<br />
<br />
Now, you said it took all winter, but it's not clear if this was 24/7 or on-and-off. For an example, let's say I have one wet spot 8" square. How many holes would you drill? How would you create a sealed vacuum over the hole(s)? How long would it take to dry out that spot?<br />
<br />
Thanks for the tip!

The amount of Vacuum you can pull on a core is widely variably depending on location and construction. It takes some experimentation to get good results. You need good vacuum, but obviously not perfect vacuum. I'm talking about a $1,000 vacuum pump designed to run 24/7, not a vacuum cleaner. On average I would say your 8" square would take a couple of weeks with 24/7 operation. I usually put a small square off bleeder cloth on the deck over the hole and pull vacuum there. Sometimes you need a heat sink over the area where you are pulling from to keep the temp of the tape from getting to high compared with the rest of the area. A hand held infared thermometer is a must for checking your set up. I had a special stand welded up for my light that allowed me to move it up and down, to vary the temp at the area i was working on.

[Scout 30]

Originally Posted by ramblinrod

Im a little confused by your terminology. Are the high moisture readings in the hull, between waterline and toerail, or in the deck.

In either case there are viable repair methods short of removing skin and replacing core, under certain circumstances.

Before doing anything, get a reputable glass guy to evaluate. Surveyors with moisture meters have been known to be wrong. He may charge a couple hundred bucks for consultation, but will likely save you thousands, by advising Pros and cons of various repair options, if any are required at all.

The "topsides" is the area of the hull between the waterline & the gunwale.

[Scout 30]

Here's a technology that I've seen advertised although I have no experience with it myself. Sounds like the vacuum method that's been mentioned.

Hotvac Boat Hull Drying, Osmosis Treatment, Osmocure

[rognvald]

Originally Posted by Scout 30

Here's a technology that I've seen advertised although I have no experience with it myself. Sounds like the vacuum method that's been mentioned.

Hotvac Boat Hull Drying, Osmosis Treatment, Osmocure

Very interesting video. However, even if it performs as stated, how would one determine if the core was degraded(loss of structural properties) or the presence of delamination? In either case, the core would have to be replaced(in my opinion) to assure a proper fix and the cost of this treatment may be prohibitive if the potential for a re-core is evident after drying. Water intrusion in a laminate is never good and usually requires drastic engineering. A reliable diagnosis from a qualified and expert fiberglass repair specialist must be done before any repairs are undertaken. Good luck and safe sailing.

[Scout 30]

Originally Posted by rognvald

Very interesting video. However, even if it performs as stated, how would one determine if the core was degraded(loss of structural properties) or the presence of delamination? In either case, the core would have to be replaced(in my opinion) to assure a proper fix and the cost of this treatment may be prohibitive if the potential for a re-core is evident after drying. Water intrusion in a laminate is never good and usually requires drastic engineering. A reliable diagnosis from a qualified and expert fiberglass repair specialist must be done before any repairs are undertaken. Good luck and safe sailing.

I think that if you could completely dry the core & then inject epoxy into it with a system similar to vacuum bagging you would end up with a structurally sound hull. I wonder if anyone has ever tried this. I think the hard part would be determining that the epoxy was fully dispersed leaving no dry spots or voids. I think multiple injection & extraction points might work, especially if you had a system that injected & extracted all of the different points at the same time.

[a64pilot]

Originally Posted by Scout 30

I think that if you could completely dry the core & then inject epoxy into it with a system similar to vacuum bagging you would end up with a structurally sound hull. I wonder if anyone has ever tried this. I think the hard part would be determining that the epoxy was fully dispersed leaving no dry spots or voids. I think multiple injection & extraction points might work, especially if you had a system that injected & extracted all of the different points at the same time.

Many aircraft honeycomb panels are repaired this way, however it adds a huge amount of weight of course and then the panel ends up with a hard spot too, and that inflexible spot can be problematic.
Aircraft are usually just de-laminated, or dis-bonded, never seen one full of water
A small wet area I think you may can fix with injection / infusion, but the bigger it is, I think the less chance of success you have.

Best course of action I think would be to find someone with a very good reputation, and let them fix it. Has to be a big bill though, I would assume, and once fixed, is it really fixed as in will not re-occur?

[Scout 30]

Originally Posted by a64pilot

Many aircraft honeycomb panels are repaired this way, however it adds a huge amount of weight of course and then the panel ends up with a hard spot too, and that inflexible spot can be problematic.
Aircraft are usually just de-laminated, or dis-bonded, never seen one full of water
A small wet area I think you may can fix with injection / infusion, but the bigger it is, I think the less chance of success you have.

Best course of action I think would be to find someone with a very good reputation, and let them fix it. Has to be a big bill though, I would assume, and once fixed, is it really fixed as in will not re-occur?

I repaired my bow last year. I had water intrusion due to a poor windlass installation. I left the outside skin alone & cut out everything from the inside. Then recored & glassed using epoxy resin. It's a messy crappy job but not really technically difficult. If I was the OP I'd just roll up my sleeves & get to it.

[ramblinrod]

Originally Posted by Scout 30

The "topsides" is the area of the hull between the waterline & the gunwale.

Yes, I'm aware, just verifying the OP is because so many use it for above the toe
rail.

For this very reason when I communicate with customers, I use:
A) below the waterline
B) between waterline and toe rail
C) above the toerail

When someone uses "topsides" you have to verify everyone s talking the same thing.

[ramblinrod]

Originally Posted by rognvald

Very interesting video. However, even if it performs as stated, how would one determine if the core was degraded(loss of structural properties) or the presence of delamination? In either case, the core would have to be replaced(in my opinion) to assure a proper fix and the cost of this treatment may be prohibitive if the potential for a re-core is evident after drying. Water intrusion in a laminate is never good and usually requires drastic engineering. A reliable diagnosis from a qualified and expert fiberglass repair specialist must be done before any repairs are undertaken. Good luck and safe sailing.

I agree with the last sentence only.

Expert Fibreglass Repair Specialist

[Stumble]

Originally Posted by Scout 30

I think that if you could completely dry the core & then inject epoxy into it with a system similar to vacuum bagging you would end up with a structurally sound hull. I wonder if anyone has ever tried this. I think the hard part would be determining that the epoxy was fully dispersed leaving no dry spots or voids. I think multiple injection & extraction points might work, especially if you had a system that injected & extracted all of the different points at the same time.

You really can't. The wood muck that is left over from rotten core destroys the structural properties of the epoxy. And the real demand for a core is to act a small a bridge, bonding the two skins together. If there is any core rot still attached to the skins, and there's always is, the rotten remains will just come detached as soon as load I sail applied. So you still have delaminated fiberglass but with huge amount she of added weight, and a partially bonded epoxy/rot core inside making a proper fix more difficult.


The reality is that a large area of rot requires cutting off the skin and replacement. A small area... well I have been known to instal slightly larger deck plates instead of doing a recoreing job.

[ramblinrod]

First of all, a wet core is not necessarily the end of the world as many believe.
Almost every cored boat composite more than 20 years old (life expectancy off bedding materials) has water in it. If there is no rot or delamination, just stopping the moisture ingress may suffice.

If there is rot or delamination, there are various repair techniques that do not require ripping skins off.

Consult a glass pro before making a mess that devalues the vessel.

[rognvald]

"If there is rot or delamination, there are various repair techniques that do not require ripping skins off." ramblinrod


Rod,
Perhaps you can share these techniques(not previously mentioned) to help the OP better weigh his options after inspection by a fiberglass specialist. It would also be informative to many of us who repair our own vessels. Most of us are always looking for a better mousetrap. Good luck and safe sailing.

[ramblinrod]

Originally Posted by rognvald

"If there is rot or delamination, there are various repair techniques that do not require ripping skins off." ramblinrod


Rod,
Perhaps you can share these techniques(not previously mentioned) to help the OP better weigh his options after inspection by a fiberglass specialist. It would also be informative to many of us who repair our own vessels. Most of us are always looking for a better mousetrap. Good luck and safe sailing.

Every job is different and requires thorough inspection and evaluation before a specific repair method can be recommended. A good book on Fibreglass repair techniques will be 100s of pages. After reading, one will have some book smarts, basedbelieve on one authors input, the readers comprehension, and ability to apply that with established practical skills.

[rognvald]

"Every job is different and requires thorough inspection and evaluation before a specific repair method can be recommended." ramblinrod


Agree completely, rod. However, what other "various repair techniques" you refer to earlier would be effective for the OP's boat assuming the core is wet and has delaminated that "do not require ripping skins off?' Thanks.