boat rot...wet foam prevention.

[salty87]

Re: boat rot...wet foam prevention.

I'm going to be replacing everything (floors, stringers, foam, etc) in my 1988 Sea Ray once the season is over. First off, I will be fiberglassing all of the wood that I put in on all sides and also going back in with expanding foam through holes in the floor. But it seems to me and many others that there needs to be a way to keep the foam and thus trapped water off the wood. I have been toying with the idea of using something like this between the stringers and the foam and on the underside of the floor. Maybe not that exact product, but it gives you the idea. You could just use some dabs of glue to hold it in place and then once the foam is poured there will be an air space next to the wood.

Do you guys think this has any merit??

trash bags like above work and are pretty cheap. i wouldn't want whatever metal that is in mine.

 

[109jb]

Re: boat rot...wet foam prevention.

trash bags like above work and are pretty cheap. i wouldn't want whatever metal that is in mine.

It isn't metal, it is made of plastic material. Trash bags don't give you an air space which the product I posted would. This would also give any water that got in the boat a path to get out too.

 

[Aaron Silidker]

Re: boat rot...wet foam prevention.

New guy here, I have some experience floating cars using foams so I thought I would chime in. In my 4 years of college experience getting small cars to float we tried 4 different kinds of foam, getting better every year.

Year 1 was pink/blue foam. This stuff sucks. It doesn't float very well and absorbs a lot of water

Year 2 was expanding foam. Again doesn't float very well, and absorbed a lot of water

Year 3 we found the foam that they make fun noodles from. This stuff was much better than year 1 and 2 but it still absorbed water and was HEAVY! I can try to find the name of this stuff for all those interested. It can be "glued" together with a heat gun. It comes in giant sheets and comes in all different densities.

Year 4 we used flexible expanded polyethylene, basically flexible closed cell styrafoam, the same stuff used beneath boat bumpers. It was great for us because it was light, didn't absorb much water, displaced a lot of water and it was machineable. It is easy to shape with an electric knife.

Hope that helps! If I were doing a boat I would use the flexible EPE, it works very well.

 

[charliedaubitz]

Re: boat rot...wet foam prevention.

this outfit is in my town, http://onsmartpages.com/powerfoaminsulation/products/#flotation it's what I'm using, cut to fit. I'm thinking of coating it with water based epoxy and mounting it in the gunnels with velcro or a couple of carriage bolts from the top.

Powerfoam EPS flotation will support 50 pounds per cubic foot when fully immersed in water. To estimate the amount of EPS flotation needed for a specific project, estimate three (3) pounds per board foot of lumber to be used building the dock plus 180 pounds per person on the dock at any given time and divide by 50. This figure is the number of cubic feet of EPS flotation necessary to support the structure and its occupants.

BLOCK SIZE MAXIMUM WEIGHT

12" x 48" x 96" (32cu. ft.) 1600 lbs.
18" x 48" x 96" (48cu. ft.) 2400 lbs.
24" x 48" x 96" (64cu. ft.) 3200 lbs.
36" x 48" x 96" (96cu. ft.) 4800 lbs.

this is what my sub-floor looks like, I've decided to use 1/2 " MDO board with epoxy paint on both sides and all the screw holes.

 

[proshadetree]

Re: boat rot...wet foam prevention.

I left foam out of mine made 6 compartments down each side 4 in middle Jetted with 1/2 pcv tube at lower v sealed as best as i could to floor.Ideal was if it got a hole only the affected side flooded.These were drained back to bilge area.2 pumps 1 auto 1 manual.If sealed only one side floods.Floor seals at top separate panels seal sides and down middle.Also will brace hull and floor.
Wish I had taken pics when I done this but daughter had my camera

 

[clarkw]

Re: boat rot...wet foam prevention.

Just a thought, but we use a "Seal-a-meal" for the freezer. The bag material is a tube that you seal on both ends to form a bag. A person could seal one end of the bag material, place it between the stringers and fill with foam. Once foam has expanded and outgassed, seal the other end. This would effectively waterproof the foam.

I haven't tried this and have no idea if it would be practical, but the problem seems to be allowing the foam to absorb water - this would seal the water out of the foam.

ClarkW

 

[rngale]

Re: boat rot...wet foam prevention.

I think the foam will eat the plastic freezer bags

 

[sinker6]

Re: boat rot...wet foam prevention.

I'm a newbie to this site but I found this discussion to be quite interesting.
I'm a renovator of for over 25 yrs and I've used expanded urethane foam on several projects over the years. They now have several different types they spray in to wall and cieling cavities and the insulating values are increasing by encapsulating air thus giving it great buoyancy. they are also impervious to water and quite inexpensive.
that being said, the problem of rot is that water finds its way between the foam and the stringers with no way to migrate back to the transom drain or bilge area at the back of the boat and there is also no air circulation to dry up the moisture.
laying in some type of perforated pipe similar to a "big-o- in foundation drainage" but of a smaller diameter along the stringers under the foam would allow that moisture to migrate back and also let air circulate through that area to allow it to dry, there are also drainage mats that could be laid down before applying the foam to allow air movement while still giving the hull some strength.
I definitely feel the foam also acts as a structural enhancement of the hull so i would definitely put it in.

john

 

[sinker6]

Re: boat rot...wet foam prevention.

Further reading and I agree with Old Salt Oz, Seal every thing up well and have good drainage.
john

 

[tboydva]

Re: boat rot...wet foam prevention.

I have a potential solution which worked well on my boat. I cut a 3" piece of PVC pipe down the middle (lengthwise), then drilled a bunch of holes in it. I put it in the "lowest" part of my hull, then covered it in several layers of paper mache. Paper mache turns to mush in water (it actually turns to mush if you have it mixed to watery!), but it's pretty hard and impervious to solvents when dry. Anyway, I foamed over it, then tested with water pumped into the bow. It ran right out (with some bits of paper goo). Visual (with a mirror and light) leads me to believe that my drain is intact pretty close if not all the way to the bow. Anyway, I'm feeling the foam will drain (at least over longer periods of dry storage). Here's a picture (kinda' hard to see, but it looks like a wad of newspaper in the middle of the hull floor).

Tom

 

[charliedaubitz]

Re: boat rot...wet foam prevention.

I went to Powerfoam here in Midlothian. Bought a 12' long scrap block that gave me more than I needed for $20.00. After cutting one piece with a hand wood saw, I tried my chain saw on it and it worked perfect.

 

[colobiker]

Re: boat rot...wet foam prevention.

all,

I started reading this thread, and instantly thought of an Idea.

I used to work for a manufacturing company, they had these plastic bag looking things. with the 2 part foam in them. they break the capsules.and it mixes and expands.. inside the plastic bag.. these bags have no air in them and are completely sealed to keep the foam from sticking to the thing the foam is protecting

if you buy something that has a thin silve plastic bag filled with foam.. that what it is.. you put the bags in the space you want, break the capsules holding the 2 part foam the foam expands and fills the voids.. (we were using these in cardboard containers and they never pushed out the walls.... once also I would see them take ordinary plastic trash bags.. and spray the 2 part foam in, and it would expand.. it sticks to the plastic, so if you sealed the plastic up, if might work.. as long as its air tight..


if you guys already talked about this i appoligize.. I diddnt read the whole thread.. (time constraints)

 

[salty87]

Re: boat rot...wet foam prevention.

seems like there's some focus on keeping water and foam away from each other. while that's a good goal for the long-term, the foam itself creates a skin that will keep water out (unless the foam is locked in a wet environment for years). finding a way for any water that might contact the foam to drain out should be the long-term goal, in my mind. this includes not allowing water to pool on top of the foam.

jam enough these bags of foam into a wet area and it's a guess as to whether the plastic bag will break-down over time. it adds another question mark into the problem. who knows?....my point> don't forget the drainage.

 

[Seadooman03]

Re: boat rot...wet foam prevention.

Bumping this thread after reading the entire thing.

I made a thread regarding my floor. I soon found out the foam is water logged. So, im going for the long haul, and replacing it all. I've worked with foam, fiberglass, resin, and all kinds of fun stuff.

So, reading threw here, i have gained alot of the "bads", and the "maybe" this works best....and of course the ping pong balls.

Many hate the foam, in my boat its diff. seems as tho its for structure strength. The company put down the decking, drilled holes, and filled away to create tension between haul and floor..(my guess at least). The floor did raise when doing so, b/c i noticed foam on the top as well..which they may have used to level out the floor b4 putting carpet down. Im not sure of the extent of water log yet, but it's wet.

My stringers, and center supports, have NO wood (Drilled..and dry), until you get to the back were the motor is attached..that wood is dry, and not damp. The rest of the boat is fiberglass, and filled with foam for the supports...(so far from what i have seen).

An idea i have come up with to put the foam in, have it stick everywhere and seal good, make a great mess, and have it be breathable.

-Put in PVC piping..(thin walled, like pex tubing and run it in an "S" curve on the bottom of the haul between stringers). Start from the back, and lead to the front, curving it back and forth, and then leading back to the bilge in one line. Prior to installing, drill many good size holes in it. Once properly attached, pour in the foam over it...(Now i know the foam has a great chance of filling the holes, but im betting if there small enough, they wont be as bad...(ill try this first outside of the boat in a test container). Now, here comes the forced vent part, attach a small pump on one end in your bilge of the pvc, it can either suck air/water out, or push it threw to vent under the foam>>>

**edit** I do like that black matting that was brought up in this thread as well, alto i am concerned about its weight. You could very well lay that on top of the pex/pvc piping then pour the foam on top of that....so the water would actually leak down and threw, and you could push/suck air around it.


Comment's suggestions?

 

[tboydva]

Re: boat rot...wet foam prevention.

I had very good success with using a PVC pipe with drilled holes as you suggested. I ripped it down the center, then put it down my centerline. I used paper mache. It worked very well. I coated the entire PVC pipe and "feathered" the mache onto the boat hull so the edges were covered. Mache is like mush in water and essentially dissolves. Let it dry really well and since it's water-based, the solvents from the foam won't harm it. I can shine a flashlight down and see the intact "tube". All the paper's dissolved away. Put it under consideration!

Tom

 

[Mark42]

Re: boat rot...wet foam prevention.

Just do as the CG suggests and put the foam above deck and leave below deck open and vented. Fill the under gunnel areas full of foam. Maybe even make the deck itself a 2 inch thick slab of foam encased in glass or PVC for additional flotation.

 

[bob johnson]

Re: boat rot...wet foam prevention.

kinda two subject at the very least here...rotting wood and water logged foam.

they make foam for docks that sit in water all year.. that dont fill with water?

if you used that foam and TRIED to seal it...youd think youd be ahead of the game...now i dont know what kind of foam most makers are using., but i did burn a bunch of foam two years ago...a bunch of dock foam i was saving..a bunch of lobster bouys I had saved.. and some misc foam..and the stuff burns like solid gasoline!!!!!!!

I wonder if the boat mixed foam is also flammable..if so then the dock foam is just as good an idea..

but the best idea is NO WOOD period

with all the plastic and composites...why would anyone replace rotted wood with more wood?

and if you HAD to use wood..because of costs or what ever and you sealed it before and after installation....youd be way ahead of the game

the boat would outlive you!

bob

 

[waterwezl]

Re: boat rot...wet foam prevention.

IMO Bob's right, NO WOOD! I'm leaving the foam out of mine with plenty of drainage to the bilge and, as Mark42 said, I'm putting foam above the deck. Once I get the glass out of the cap I'll flip it and use slats wrapped in waxpaper on the inside edge of the cap where it goes over the hull and pour foam in the recess. Once the foam has expanded I'll cut off any excess and remove the slats (the waxpaper should aid in that).

I think that doing it this way, if the boat tries to flip over the foam will keep the keel down since that would be the cg. If it does manage to get upside down there should be enough foam to keep it afloat. I'm no engineer but it's logical.

Just my two cents, Jason

 

[oops!]

Re: boat rot...wet foam prevention.

welll,,,, what can i say........

composits instead of wood are allways the best.......but in a standard 16 foot boat.....the composits cost out weigh the benefits!....

keep in mind that in a properly restored boat.....the wood glassed over......will last 20 years or more......

this is far longer than the average boat owner will care to own the boat....

the cost of composits....(ie, penski board....ni-da core.....ect...ect) far out weigh the benefits......

thats why us back yard boys use wood.

we all would love to use composits........(dont jump on me erik (for the improper use of the word composits...)).....but the coat far out weighs the benefits at this time.

cheers
oops

 

[J. Mark]

Re: boat rot...wet foam prevention.

All this talk about rot has me ready to change my decking plans from plywood to 1" teak slats with 1/2 spacers to make a "grate" and just let all the water get in that wants to, but to have drainage and airflow (And extra bilge pumps)

As for flotation, I'll just tie some duct taped coolers to the deck

Seriously though what about using the 4 pound foam instead of the 2 pound foam? Isn't it far more water resistant?

The paper mache idea to keep drainage channels open was . . . pure genius.

I had been trying to think of a way to do that and waxed rope was as close as I ever got to a decent idea.