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Old 09-20-2004, 12:39 PM
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Default Foam Filled Hulls???

I was told by a boat dealer who was badmouthing a competitor's boat that:

"A Twin Vee is a foam filled hull(as advertised) which over time moisture will find its way into and eventually make it a heavier boat."

I'm asking is this true or not, and reallistically, if so, over what period of time?
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Old 09-20-2004, 12:48 PM
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Default RE: Foam Filled Hulls???

In the past, the 20 and 22' Twin Vee hulls had a reputation for developing water intrusion problems under their decks.

It is my understanding that this has been addressed, but if you order one, it might be a good idea to let them know that you will not accept the boat if you see any problems with this, and that you will be looking.

This info is from articles that I have read not seen, so take it for what its worth.
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Old 09-20-2004, 12:49 PM
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Default RE: Foam Filled Hulls???

Foam that is constantly in contact with water will eventually absorb it and become heavier. This is true even with closed cell foam.

In a well constructed boat the foam should only have minimal contact with water until seals start to break down after many years. One common example is with foamed in fuel tanks. Eventually the seal around the access deck will break down and allow rainwater and spray so into the gas tank area. This can happen in any section of the hull that is foamed and has some sort of access (rod holders, deck plates, hatches etc.)

This takes many years and can be generally be prevented by replacing the seals periodically.

On a boat that is not well constructed the water penetration can begin almost immediatelly, but it still takes time and a lot of water to make a boat noticably heavier.

So, he is correct, but a lot of great boats have been on the water for a long time with foam. Just look at all the Whalers and Makos that are still around.
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Old 09-20-2004, 12:50 PM
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Default RE: Foam Filled Hulls???

I suppose it could be true, but the reality is that most, if not all boats that are foam filled use close celled foam which is designed to not absorb moisture. Don't take that as gospel, I have heard of some Whalers that somehow or another gotten their foam waterlogged. It would still float, but it was considerably heavier..
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Old 09-20-2004, 12:52 PM
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Default RE: Foam Filled Hulls???

Lots of info on twin-vee boats, do a search.

Any boat will get "wet", if not taken care of.
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Old 09-20-2004, 01:07 PM
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Default RE: Foam Filled Hulls???

To clarify, the old TV's were reported to lack a proper seal due to sloppy work under the harder to see (and work) areas under the bow and stern platforms where the deck and hull joint needed more attention.

Looking at the weights, the TV is a very light boat and uses this factor to get good milage from a displacement hull. But as fiberglass thicknesses are hard to control (especially hard on double hulled cats) I suspect that TV is relying on the foam to fill and provide some structural strength to a thin hull, that in spots, is probably thinner than in other places, and needs the support.

Water intrusion in the foam is a problem in terms of weight, but if it gets between the foam and the glass on a light hull that flexes, then it can break down this seal, causing the hull to lose more stiffness, and will speed the process like a clothes washer.

Evidence of this usually reports to the bilge where you will see some small to large chunks of floating foam in terminaly advanced cases.

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Old 09-20-2004, 01:18 PM
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Default RE: Foam Filled Hulls???

I have some very recent real world experience with water intrusion in a foam filled compartment. My boat had about a dozen unsealed 1/4" screw holes below the water line from some really bizarre activities by the previous owner. They were hidden by 16 years worth of bottom paint on a boat that has spent nearly its entire life in a wet slip. I know it has been in my slip nine months per year for three years. So it had plenty of time for the foam to soak up water. Since I had heard and read all of the horror stories I opened the compartment up and dug out the foam after i found those holes. It was a nightmare and a complete waste of time because the foam had not actually absorbed much, if any, water.

It felt wet to the touch but you could not squeeze any water out and it weighed almost exactly the same as the dry foam that came out. Plus when I left the foam sitting, it quickly drained by itself and almost no water collected. So, if I ever find a similar situation, I will drill holes to let it drain over the winter, reseal the holes and forget about it. Apparently the old adage about hanging little Whalers up to dry works.

A lot of that no doubt depends on the type foam the manufacturer uses. The foam in my boat had the density of rock. It was hard to even drive a chisel into the foam. It was waaayyyyyy denser than the two part stuff I have used in building my own boats and pretty much incapable of holding much water. Shamrock was not kidding around when they poured this stuff in the compartment. If every compartment in my boat has leaked consistently since 1988 (which they probably have), I doubt that she would even hold a couple of gallons of water in the two nearly full length foam compartments.

Like I said, the results probably differ by builder, but I know that my boat isn't going to gain much weight from saturated foam. The stuff in there just doesn't hold enough water to add up to anything. Now about those delamination concerns, those are very real.
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Old 09-21-2004, 02:12 AM
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Default RE: Foam Filled Hulls???

Do they use open or closed foam in the construction process? Closed foam will not absorb water...
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Old 09-21-2004, 10:09 AM
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Default RE: Foam Filled Hulls???

"badmouthed by a competitor".....first clue, I visited a boat dealer that had a scrapbook filled with snapshots of the competitors boats pointing out their construction techniques and shortcomings, stating that their boats were far superior, none of the photos I saw were of critical components, some wiring was grouped together and wire tied en mass, non-finished glass areas in the bilge, the dealer's boat was 30-40K more but never mind that, the twin vee issues were related to cheap hatches, allowing water into the bilges, the only foam issues were of early models, I haven't heard of any water absorbtion into twin vees in years, 99% of all small boats have foam somewhere, to pass the coast guard regs, (it's safer too), ...would you expect a boat dealer to sing the competitors praises?....they are SALESMEN....they want you to sign on the dotted line.......Mick
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Old 09-21-2004, 12:08 PM
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Default RE: Foam Filled Hulls???


I have actually encountered dealers that don't bad mouth their competition. Rare, but they still exist, now pricing thats a seperate issue.

For the record, anything a pushy salesman states I take with a grain of salt, but I thought there might be some truth in what he said, and thats why we all rely on THT website for answers.
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Old 09-21-2004, 08:11 PM
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Default RE: Foam Filled Hulls???

buddy has a twinn vee.~6 yrs old. He had water get into his hull. Had poor design and sealing where wiring and control cables exited deck to go to motor, allowed water into hull, where it drained into one hull and made boat lean. He installed garboard drains in hulls (there were none), improved sealing, and no more problem. closed cell foam doesnt pick up water, at least not over short durations

The twinn vee is a very sturdy constructed hull, its one of its strong points. Its not thin 1/8" glass sides like so many cheap boats are. the hull side on his is cored with plywood in places for stiffness. there is no hull-deck joint, I think his deck and transom are wood cored, fully glassed to the hull. He uses it hard and its held up good. They may use different coring materials today. they have been improving and up-scaling them gradually.
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Old 09-22-2004, 12:38 PM
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Default RE: Foam Filled Hulls???


Always like good info from owners. Your info is right in line with what the manufacturer said. They told me they had issues back in 1999, and it was addressed, and corrected.

Wood in construction doesn't scare me like it used to. If these boats were bad there would be more on the used market.


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