drying out hulls

[rancher44]

Looking at an older Lagoon seller says it need all the bottom stripped and allowed to dry out for an off season then mew bottom paint ,
Is this normal on older boat or does that mean the core has got water?

Any advice would be helpful ---Naturally I would have a boat surveyed and hauled but if it is something that is a problem I don't want to go to alll the expense

[pbiJim]

My only experience with that sort of thing was on a little 13' Boston Whaler. Those things have some sort of foam core with glass on both sides. They are darn near impossible to sink if you hit something, but once the glass is cracked, that foam core slowly soaks up water.

Back in the early 1980's I got my hands on one that was probably close to 400 pounds overweight with water saturation. We drilled 1/2" holes in the bottom on about 4" centers & let her sit on the hard. It took 3 years for that hull to get back to normal weight. Then she got some fresh glass, went back in the water & got sold after a season of normal use. She seemed OK after the repair.

I don't know how a Lagoon compares to that.

[boatpoker]

Make an agreement with a surveyor on a price for a bottom inspection only with the understanding that it may evolve into a full survey only after bottom condition is determined. It is imperative that you attend to discuss the condition and give him the go or no go.

Re-core work on a bottom is hideously expensive. Good luck

[colemj]

Or, depending on the Lagoon model, just walk away and look at the one sitting right next to it. Some of the models are a dime a dozen on the used market.

Mark

[Pblais]

Is this normal on older boat or does that mean the core has got water?

It means the fiberglass has a high moisture reading. If the core was rotted (as in high water content) that issue would be possible to determine. Drying out a bottom may be required. You can have the bottom evaluated but you can't always know why. A limited survey is always possible if you ask for one up front. It would usually involve the time required plus travel both ways. If you asked for a full survey with this item checked first you can usually ask for the surveyor to stop the survey with no written report at a reduced fee. I would do that and if the results are acceptable or nearly so continue with the survey and latter decide if you want the boat or not.

There is a limited amount one can determine with a moisture reading and good thumping. Visual inspection might indicate something you might not notice but you won't get much more. Surveyors don't have xray vision. They can spot warnings you might not see and those are what you can expect from a good surveyor. You could buy the boat and still have problems. A survey is not a warranty but is good insurance.

[Sand crab]

You don't say the size of the cat but the price on this one better be cheap. Stripping, drying and reglassing will be like buying a new Buick. Maybe a Caddy.

[FLLCatsailor]

I would run...

[SunnySky]

I 2nd the run comment.. Work below the waterline means time in a yard that can add up to a lot of unexpected expense even if you did all the work yourself and were getting good prices on all your materials, most of the work above the waterline you can at least be enjoying a mix of sailing and boatwork instead of just boatwork without the ability to sail. Not to mention regarding the removal of bottom paint many yards would not allow you to do any of that portion of the work yourself which equals even bigger expense.. It's still a buyers market given the state of the economy so take your time and be picky before even spending the money on a surveyor.. (and more important than a surveyor in my opinion is befriend a local catamaran owner that built their own boat because with a very quick kick-the-tires kind of visit to the boat they can help you know in very general terms what you are considering getting yourself into before digging deeper and going through the survey process..)

[SunnySky]

Also regarding Lagoon specifically, which I have only gone on a demo sail on them, you might want to check out:
http://www.cruisersforum.com/forums/...nce-87514.html

[rancher44]

This is all very useful thanks
Can this problem be avoided by using epoxy primer and then doing the bottom paint ?
Naturally on a clean hull

[FLLCatsailor]

It is always a good idea to have an epoxy barrier coat between the gelcoat and the bottom paint.

[Sand crab]

So what's the back story on this one? Deferred maintenance? Model?

Is this the one that took on significant water in the Carib. Maybe a TPI. Inside is just about trashed.

[boatpoker]

Originally Posted by FLLCatsailor

It is always a good idea to have an epoxy barrier coat between the gelcoat and the bottom paint.

Don't think I'd say "always". I see many barrier coats applied to older boats fail because they were never dried out it the first place. All older FRP boats do have some moisture in the hull and this is not always a problem. Polyester resin is hygroscopic. Barrier coating an older hull often traps moisture which will eventually blister the epoxy.

A lot of newer boats are made with isopthalic, NPG or vinylester resins which rarely (ever ?) blister. Dealers and yards still push sales of epxoy barrier coats on these boats even though they don't need it because ..... well, thats what they do.

[Cotemar]

I would 3rd the RUN, RUN, RUN comment. And do not look back as the broker may be chasing you.

[FLLCatsailor]

Originally Posted by boatpoker

Don't think I'd say "always". I see many barrier coats applied to older boats fail because they were never dried out it the first place. All older FRP boats do have some moisture in the hull and this is not always a problem. Polyester resin is hygroscopic. Barrier coating an older hull often traps moisture which will eventually blister the epoxy.

A lot of newer boats are made with isopthalic, NPG or vinylester resins which rarely (ever ?) blister. Dealers and yards still push sales of epxoy barrier coats on these boats even though they don't need it because ..... well, thats what they do.

I agree with you about failure when boats are not dry to begin with. On newer boats it is still a good idea to add a barrier coat IMO... I mean you spend a couple hundred grand on the boat, what is a few thousand to ensure you will never have to worry about blistering?