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Old 02-23-2003, 05:40 PM
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water logged floatation problems

I just purchased a 1965 Chris Craft Corsair-Sun Lounger, It is a 18' fiber glass boat. I was amazed at the perfect condition the boat, engine, outdrive was in. HOWEVER,,,,,,,,, I was going to clean the inside out. I tilted the boat up and removed the drain plug. I noticed a little water coming out. I thought it was just some water that might have slipped in with the last rain we had. Much to my surprise, the water just kept coming out. I noticed it was coming from around the front engine mount on the floor. I removed one of the engine mount bolts. That's when my dreams came crashing down around me. It appears that while it had been stored outdoors with a cover for a few years, water had penetrated the subfloor area. I called a friend who does fiberglass work. He removed a 12"x12" area of the floor. The floatation is soaked. I have put the boat in an almost straight up position. Some of the water has drained, but it appears that the whole floor has to be cut out. Then I would have to remove all the foam ??????? Is this the only solution??? Do I have to put new foam in??? It looks like it was sprayed in. I knew the boat seemed a little heavy, but I thought it was a solid boat. What to do. Will the stuff ever dry????? The floor is molded in to the boat. So it will need to be cut carefully. Any ideas??????

Thanks for any and all responses,
Mr. Lamothe
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Old 02-25-2003, 02:23 AM
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I've heard of people speeding up the core or foam drying process by:

1.) drilling a pattern of 1/4" holes and using either a shop vac or a vacuum bagging pump combined with a condenser (so the water won't harm the pump) to try and suck the water out of the core.

2.) drilling two holes, one at a high point and one at the lowest point possible. Then hook an air compressor up to the higher inlet hole and apply some air pressure to try and force the water to migrate out of the foam faster.

I have no idea if either of these methods will work, but it could be something to look into.

If the boat is stored indoors and kept on a trailer in the summer covered well, it might be ok to simply let the foam dry out, especially if itís just in the cockpit floor that itís really wet right now. The mention that ďit was coming from around the front engine mountĒ makes me worried though Ė I donít know how your boat is built but I would be concerned if the stringers, etc. are isolated from the wet floor. If they are waterlogged or rotten, you could be in for bigger problems in the long run.

If the boat is kept in the water where it will always be a little damp, or if the water is near any structural areas, e.g. the stringers supporting the engine mounts, and the boat is otherwise a nice boat, I would be inclined to address the issue now, removing the foam, replacing it with good quality closed cell foam that will not absorb water, and then re-glassing over it.

This page makes for an interesting read: High Tech Materials In Boat Building
- The Pros and Cons of Space Age Materials in Boat Building What it Means for the Consumer by David H. Pascoe, CMS
if you're on the edge trying to talk yourself into a rebuild-process. The picture half way down and the quote "The gunk pouring out of this hull is the result of complete water saturation of the foam core. Hydraulic action - panting of the inner and outer skins - pulverized the foam and turned it to black mush. Once the foam degraded, the laminate weakened and split open, sinking the boat" would probably be a good one if you're trying to talk yourself into redoing it.

I'm really not sure how severe the problem is or what all structures might be waterlogged right now or over the long run either casuing a loss of stiffness or casuing other structures to flex, rot, or fail. I wish I was more familiar with your boat.
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Old 02-28-2003, 03:51 AM
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Panel beater/auto spray painters "Baked enamel" microwave oven...park boat in and turn on...

3 mins at high or until the egg you put on the front seat is hard boiled! ;o)

Take that with a grain of salt (the egg!!)

OK - look I was jesting with the 3 mins and egg, but a microwave oven big enough to get that boat into might turn the water to vapour and expel it under pressure as a gas thru the bung holes etc...

Obviously you'd remove things like batterys and any expensive electrical equipment like sounders radios and the well as any removable seats cushions, upholstery etc.

If it works - sell it to some other sucker fast as likely the wooden stringers and transom etc are likely could tell with a non invasive moisture meter available from Tramex (do a web search) whether the transom and stringers are saturated from outsie the hull.

If they are saturated then bank on em being rotted - fresh water (rain, lakes) rots wood fast, saltwater (ocean) doesn't.

You bought a pup - sell it quick.

At least it'll be lighter and go faster when you sell it after the waters out!

caveat emptor...

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Old 02-28-2003, 06:19 AM
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OK - look I was jesting with the 3 mins and egg, but a microwave oven big enough to get that boat into might turn the water to vapour and expel it under pressure as a gas thru the bung holes etc...
This makes me ask what temperature does fiberglass start to distort at? It's relatively low for non-tooling normal boatbuilding resin, isn't it?
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Old 02-28-2003, 09:45 AM
midnightkayaker midnightkayaker is offline
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I don't have a lot of experience with drying out hulls but I am in the process of hacking my way through a deck/transom/rubrail replacement on a worthless skiff.

I'll give you my two cents worth one penny at a time:

First of all, when it comes to houses and boats ANYTHING IS REPAIRABLE.

Second, that's a cool boat and if you like the model then replacing the deck and stringers (and all the other things you discover) is time well spent.

good luck, and post some photos please.
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Old 02-28-2003, 11:41 AM
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gonzo gonzo is offline
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The only way to get a satisfactory repair is to cut out the rotted wood, remove the waterlogged foam and replace them. Vacuum cleaners and drain holes will only get the water that's sloshing around. The foam in many old boats is "open cell"; in other words a sponge. Some of the low density close cell foam will deteriorate with age and the walls between cells break. It will also absorb a lot of water.
How does the plywood look in the area you removed? It is possible to remove the foam by cutting access holes, breaking it and then using a vacuum cleaner. The stringers are structural and an area of concern. The foam is also structural because it forms a beam between the bottom and the floor.
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Old 02-28-2003, 03:12 PM
Mike D Mike D is offline
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Mr Lamothe

Near the end of your posting you ask a few questions but you full well know the answers.

What is not known is the scope of the damage but it is quite clear that is is extensive.

There is not much choice is there?
  • Cut your losses and get rid of it.
  • Spend a long time removing the damaged parts and renewing them.
High-tech micro-waving may work but then again it probably won't. Vacuuming and blowing hot air through might work but probably not. These would only dry the damage anyway, they can't repair it.

But (trouty will like this one) labor omnia vincit and at the end of it all laborum dulce lenimen

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Old 03-03-2003, 08:24 AM
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I guess the point with microwaving a hull to dry foam is this.

Some cars have fibreglass bodies - and even some metal ones have fibreglass panel repairs.

These "baked enamel" paints are then "microwaved" bye the auto body spray painter in a microwave "baked enamel oven".

The painter sould know the capabilities of his baked enamel oven.

It wouldn't IMO (no humble) hurt to ask a baked enamel oven painter if he thinks it would work.

Good luck, maybe if you put enugh eggs on the front seat, when they are hard boiled you could sell em and pay for the microwaving with the profits! ;o)

as an afterthought - you could always put a piece of wet foam and a small piece of fibreglass into the microwave baked enamel oven as a test first to see of theres any problems with either material.

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Old 03-03-2003, 10:20 PM
Tom Lathrop Tom Lathrop is offline
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All of the floatation foams usually used by manufacturers are susceptible to solvents. Gasoline is a prime example. If you pour some into the foam compartment, the foam will turn into a liquid of small volume. There are also solvents that are probably safer to use but I'm not a chemist. Might help to get a better handle on the problem without spending a lot of loot.
Tom Lathrop
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Old 06-09-2003, 09:27 PM
Black Bart Black Bart is offline
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When you get a lemon you make juice right? While cutting your losses may seem the prudent thing, few things are as satisfactory as repairing your own tub. So get yourself a decent jig-saw, and set the blade 1/16" less than your floor thickness. This is one of those situations where EXTREME patience must be used! Your problem now can be fixed, but you get too crazy with that saw and you're sunk. Don't mess around with trying to drill and dry and all that BS. Tear out the whole floor, replace it with a marine grade plywood from a reputable lumberyard(ie:not a hardware store). Be sure to get a proper seal using marine silicone and purchase a 2 part foam kit. Oh yeah, leave a de-humidifyer in the shop the whole time. Not a bad few weekends of good ol work and you'll be back on the water, and proud of yourself to boot. Good Luck Man!

**And if you biff it up, say hello to Davey for me! HAR HAR HAR ME MATEY'S!
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Old 06-26-2003, 09:32 AM
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wet core

Have a look at <>
These folks have found a way to fix your problem, and there are several places that have their equipment in use. I have no idea what this service costs, but if youy can get the water out before the stringers are gone, it has to be worth every penny!!
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Old 06-28-2003, 09:03 PM
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ted655 ted655 is offline
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Try this site

The article may be arcived by now.
. .
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Old 09-20-2003, 06:58 PM
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Saturated Sub Flooing

my boat would never get out of the water fast enough i tried prop after prop, someone suggested a posible foam saturation...

I have a problem alright exept i do not have foam i dont think.

I drilled a 4" hole in the center of the floor of my 16' Renkin Boat to find wood that is soaked!

It seems like the wood is molded in to the shape of my boat bottom.

Question is how much does the boat depend on that wood for strength? can i just cut it all away and add foam?


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Old 03-06-2004, 05:22 AM
troy morse troy morse is offline
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Been there,done that .One good answear as mentioned above is do it right the first time.Tear it all out,Shovel work good on the foam,if the foam is that bad then your floor is bad also.I like putting in the foam loose.Any water can be drained easily in the future.Supper seal your new stringers and deck,especially on the underside or you'll be back again within a few years.I don't like poured or blown foam for the reasons you are now suffering.
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Old 06-06-2004, 10:38 AM
paintacar paintacar is offline
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Location: illinois
I have a water soaked transom

Hi everyone, I have a thunderbird tri-hull, I don't know what year it is, but it is 20'. The boat seems to be in good shape, no hits or anything, however it was sitting, with the front elevated, for about ten years. the drain holes were clogged, and it had about 3" of water in the hull, at the back and in the two rear compartments(center) going from front to rear. I cleaned everything real good, and the fowardmost compartment seems fine, no problems, the wood is good and dry there.however the next compartment back which seems to be sealed off from the outside it has a 6" inspection plate with a gasket, well when I drained it the next day there was 2" of water again in that hole only. I dried it out again and it did not fill up with much again, maybe 1/2 " . we thought everything was fine, so I painted the floor started routing all of the cables for my motor, and when I used a hole saw on the rear deck section between the motor and the inside of the boat (this section is horizontal) for the power tilt lines to run through, I noticed that the board there is soaked, and soft like balsa wood. The floor of the boat is all dry and good. Then I wondered if the transom was the same, so I drilled the 1/2" hole to mount the motor, and the wood in the transom is wet too, and seems to be soft, there is a metal plate on the back inside and outside where I drilled also It is a 1978 merc 150 H.P. boat is rated for 250. I am worried about this, everything I have done so far I fear wasted. I am a autobody tech. and no spraybooth bake cycle will dry anything out, so don't even suggest such non-sense a spay booth uses natural gas and runs about 170 degrees. I am not up for removing any fiberglass or wood in this boat. I have done my share of fiberglass work, and it is not easy to just do it and have it look right, you need to also gelcoat and its not what I am interested in doing. I agree if the foam is saturated in the other guys boat, the only fix is remove it.Is there any thing I should really worry about with my boat, or is there another fix of reinforcing it?
thanks, paintacar
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