[craig]

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I have a question. How often does or do the owners of Carolina boats remove the glass off the bottom of their boats to dry the wood? I have a striped planked on frame that reads high on the moisture meter below the water line on the outside of the hull but inside the reading is low. The boat was glassed on the outer side and epoxied on the inside from day one. she spent most of the last 12 years in the water.
Craig

 

[THOMAS70]

Never if they are built right.

 

[uncljohn]

Just be happy you don't have a blistering hull.

Epoxy is not waterproof, which is why you have to put a barrier coat over it. Otherwise it will leech water into the ply, gradually over time. Often times boats w/ wood cores will have to have a new barrier coat applied, especially if its spent 12 years straight in the water. The bad part is that you'll have to power plane the gelcoat off, let it dry, sand, apply a new barrier coat, and apply a new gelcoat (or just paint the barrier coat w/ bottom paint if aestetics aren't important). Same process as treating blisters, just more widespread, and you need some dry time.

So, to answer your question about how often, I'd say once in a boat's lifetime, if necessary.

 

[THOMAS70]

Uncljohn, epoxy resin is waterproof. So is vinylester resin, however polyester resin is not, boats that are built with polyester are ones that should be barrier coated if left in the water. Many higher end boats are built of vinylester resin below the waterline to aviod water intrusion. Also gel coat will not stick to epoxy resin.

 

[uncljohn]

Thanks for clarifying Thomas. I don't think Ship Shape TV went into details about resin differences like that. But what do you suppose this guy's carolina boat is made with? And the fact that the moisture meter reads high from the outside but low on the inside pretty much tells me that water is leeching in from the outside and has only penetrated the outer layer of wood.

 

[THOMAS70]

I'm not positive but if I had to guess, I would say if it is a Carolina built boat the wood used is either Cedar or Juniper and depending on it's age it's problably cover with polyester on the outside. Polyester resin is about half the cost of Epoxy, and most of the boats built for work or charterboats years back where built cheap. Not saying it's cheaply built but the builders wanted as little investment in it as possible so their return would be higher.
Vinylester resin is fairly new to the market and only a few manufacterers have been using it in the last 4-8 years. There is nothing wrong with wood in boats, or polyester resin. But they must be properly taken care of. Most peoples problems occur from either ignorance or lazyness, then they want to point fingures at everyone else.

 

[mwa2006]

Craig

The moisture on the outside may only be in the polyester. The only way to tell if the moisture has gotten into the wood underneath is to strip off the glass and test the wood.

 

[Sandtiger]

craig,

Simply put the glass should never have to be removed and :

1) A moisture meter is only as good as the person using it.

2) Polyester resin is not waterproof and absorbs a certain amount of moisture. (epoxy is waterproof)

3) A boat that's been in the water any length of time must have at least two to three weeks to dry out before using a moisture meter.

Own experience: Had a surveyor come out and tell me my boat had a problem with a stringer based on his moisture meter. I looked for a second opinion and had another surveyor come out to the boat about two weeks or so later. He said the boat was okay.

I had the boat "repaired" and the wood in the "faulty stringer was so dry the saw blade actually burned the wood. I saved a pice that came out of the "bad" area.

I called the second surveyor (I believe the surveyor's name was Steve Knox from VA Beach) and discussed the situation with him. He's the one that gave me the information that I stated above in my opening remarks. Seven years later and the hull is still fine. The first surveyor didn't want to wait the two to three weeks. The second surveyor just happened to be called in about that length of time the boat was out of the water and also stated he wouldn't use the moisture meter prior to the boat drying out.

This is long and I hope I have not confused you.

I have an article that I found in a magazine that states,

"...it should be clear that no electronic moisture meter can provide an absolute measure of moisture content, although they do provide useful indications subject to certain limitations."

"......but the readings obtained shoiuld be assessed together with a number of other factors, such as the age of the vessel, the type of resins used, the length of time the vessel has been afloat, the length of time since the vessel was lifted out of the water, and from experience, the readings which are found to be normal and acceptable on other craft."

If you wish, b-mail me and I will make a copy of these articles and senfd them to you if you think it would help.