to foam or not to foam

Bill

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just drying out my hull after it sank and drilled some 4" holes for deck plates that should have been istalled in the first place..
I have read everywhere on other forums when anyone says anything about "foaming in a gas tank" or just "adding foam for floatation" (2 part urethane foam 2lb denisty) people get all pissy and say that it will absorb water alomst immediately, your boat will suck, etc.. I guess I just dont see what the problem is with it if its encapsulated by the stingers and the deck? even if water got in there it would be displaced by the foam and wouldnt have anywhere to go..especially if I had deck plates which I would open up once and a while to air the thing out.. opinions? am I correct by using 2lb foam if I do it?

photo 1 (4).jpg
 

maccaffray

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the foam is a good idea in theory.

however, because is doesn't fill everything all the air voids can fill with oil, fuel, fish juice, etc.....

trapped liquids tend to stank. and if you have to get those tanks out for any reason you are in for some work.

the pics are from some tanks we yanked out of a boat a couple years ago, and it was gross.

my 2 cents would be to drill limber holes so nothing can get trapped down there.

CIMG4662.JPG

CIMG4665.JPG
 

Eastporter

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Bill- I did a lot of research on the foam before putting it in my boat. A very knowledgeable guy who was a Coast Guard inspector (THT website) said that research showed that the factory poured sheets (like I used in my bilge from Lowes/HD etc) is much better than pouring your own (2 part). The reason for this (as he stated) is that the factory conditions are so exact- it IS a science. No flaws like air pockets and no possibilities of screwing up the mix (since most are amateurs compared to DOW and Styrofoam companies). As long as it is closed cell it won't absorb water. My bilge gets wet, the foam sheets stay dry. Some people say that if you cut it (as I did) it will open the pores to water absorption- true probably- but very little. It does have a negative effective with gasoline, oil, solvents etc. so it must be completely encapsulated in epoxy/cloth or make sure it doesn't come in contact (i.e. portable tanks, clean bilge with sealed gas tanks etc.). I have seen many photos of waterlogged foam being dug out of boats that are being rebuilt. Why? I assume this is due to open cell foam in older boats- or maybe two part after coming in contact with solvents that break it down. Only speculating here- but maybe the two part components were not mixed correctly. Can anyone shed some light on this? Bottom line is that the foam I used displaces water if engulfed, and provides floatation to keep the hull afloat if I hit a rock etc. There are mathematical calculations that will tell you how much foam (density or volume) you need to support x amount of lbs. I don't have the numbers but I'm sure you can google it. I tried to fit as much closed cell foam as I could in the entire bilge and hope I never need to find out if it is enough. :)
 
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El Mar

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Bill

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Well I appreciate the advice and am now a lot more informed wow.. I guess just the idea of doing it makes a log of sense .. I mean in terms of an easy job.. Mac.. I'm on my iPhone right now.. What is in the dumpster I can't see it? Easty.. So you think the way to go is to fish the floatation into the 4" holes that I drilled and coat them in resin etc to make them stay? Gonna be a real c*nt to do..I do have weepholes made from 3/4" PVC pipe in the stringers right now
 

Eastporter

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I would leave it as is (no foam). Didn't you just replace the tank and sole? I was talking about adding the foam if you are ripping the sole off. That was a good idea to add some deck hatches to see what's going on and can ventilate a little. What about your motor selection? Are you going to a four stroke?
 

Bill

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Ya I just did the deck so I was just outlining where the foam would be sitting between the stringers..I think from what you guys said Im not gonna do it.I was dying to see how the weep holes worked out after the sink so I was glad to drill the holes for the deck plates.. should have been done before I launched it but things got skipped to get it in the water (july 5th) after working on it all winter..as for the motor.. I am just gonna go with this freshwater 115 erude that I bought off some kid for now..I am putting all my funds into the right DE when it comes along this winter..this boat will just be for striper fishing so the older motor will do fine..
thanks for the advice on the foam.. I was real close last night to dropping like $300 for the foam and doing it this week as it has had enough time to dry out..
by the way I am not sure of who it was that suggested it but I wound up pumping that gas out and draining the water off and put an ad on craigslist for free gas..it was gone in an hour..fine with me.. I want nothing to do with it..
last question Easty..what did you use for your deck? or did you not replace it?
 

Eastporter

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3/4" dry pt plywood with one layer of 1708 biaxial. She's stiff!
 

Bill

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Then what did you use for paint/non skid?..did you use wax or just throw the paint on top of the glass without sanding?
 

Eastporter

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2 coats of Interlux Epoxy Primer and 2 coats of Interdeck (no sanding except faired the overlap seam down the middle)
 

El Mar

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steveinak

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Stole this from a thread on THT. I've helped a few guys chip out chunks of waterlogged foam from their boats, every handfull felt about as heavy as a brick.
Kencraftbadfloorandstringers001.jpg

Kencraftbadfloorandstringers001.jpg
 
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