Flotation Foam Opinion?

lennymoe

lennymoe

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Apr 2, 2009
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In prep for my floor stringer etc tear down and replacement I've been reading a lot about foam. Some seem to feel it is good for the structure while others say it's just there to rot the stringers. My question is about the flotation aspect. According to the coast guard regs boats under 20' have to have enough flotation foam to support the weight of the boat, motor, and passengers while swamped. I'm just wondering how many rebuilders put back in as much as they take out. For example I have those seat boxes port and starbord full of foam but I don't plan on putting them back in on the rebuild. I instead want to put in captains chairs. Should I find some place else to put the foam or no worry about it too much?
 
92excel

92excel

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Oct 6, 2008
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Re: Flotation Foam Opinion?

short answer..

Its up to you!

you did your reading now you get to decide.....
 
seaman campbell

seaman campbell

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Mar 16, 2008
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Re: Flotation Foam Opinion?

I put the foam back in mine. I did not want it to be above the deck, so, I put it between the stringers before I laid the decking down. I had thought about not putting any back in the boat, but, The foam helps the structure of the boat as well. I would say to put the foam back in.

Remember those football players who were lost? Did you see the pics of the boat floating upside down? That's right foam kept that boat afloat and kept the one survivor alive.

Wet foam will cause stringers to rot....but the risk vs reward makes that an easy choice IMO! Take the time when replacing the stringers to seal them completely. No risk of rotting then.

TC
 
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capri1600

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Re: Flotation Foam Opinion?

Excellent valid point about the football players and that was salt water which makes everything more buoyant. Freshwater needs even more help. Put the foam back and anywhere else you can find to add some. On my 1983 Capri project I too am going with captain's chairs on pedestals. My seatboxes were already gone so I dont know if there was foam in them or not. I assume there was so I am losing that. I have room under the decking to add it so I will be.
 
lennymoe

lennymoe

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Apr 2, 2009
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Re: Flotation Foam Opinion?

Wow, good point Campbell. I was thinking of some kind of bench seating running down both sides aft of the captains chairs with storage space under the cushions but I might just fill in the bases with foam instead. Thanks
Lenny
 
Mark42

Mark42

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Re: Flotation Foam Opinion?

If you put it back, follow the Coast Guard recommendation and put it above the deck, not below with the stringers. Has nothing to do with preventing rot. What putting the foam above the deck does is keep the boat from flipping over like it did on the guys in Florida. The boat might be swamped, but you are at least not fighting to hang on.

The entire underside of the gunnels can be filled, either by pouring, or by inserting rigid boards.
 
O

Oilguy

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Mar 14, 2009
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Re: Flotation Foam Opinion?

I found some Styrofoam at a local concrete store used for making those cool shapes on stucco buildings... It is sold in 2'x8'x4" and 6" thick sheets... I think you can get thicker but that was enough for me... I cut to size and put it back between the stringer but left a channel open next to the stringer with drain holes so IF any water happened to leak in there through the exhaust or elsewhere >> It can get to the bilge and be sucked out.
This foam was pretty very affordable >> $100 for the whole boat with some left over. I was curious about whether or not this would absorb water but the salesdude told me that they use this foam for floating marinas and docks... so It should be ok in my boat.... Only thing is >> Like a styrofoam cup >> It doesn't stand up well to things like gas and solvents.

OG
 
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capri1600

Petty Officer 2nd Class
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Apr 20, 2009
Messages
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Re: Flotation Foam Opinion?

...and therein is the problem with using styrofoam. If you ever have a fuel leak, and it gets to the foam, it's gone and I do mean GONE! Also. Polyester resin does the same thing so using styrofoam below deck and then glassing it in with polyester resin whether made into a fillet material or laminating glass in place can be a problem to that foam too. Keep these things in mind when placing styrofoam.
 
C

cjd

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Sep 3, 2003
Messages
11
Re: Flotation Foam Opinion?

pourable foam is expensive, and while it may not casue rot, it certainly creates a condition where rot can prosper.

That said, I will be taking my family out. I am adding back foam and just cutting back on food and medical care for the kids.


Did I mention how expensive it is?


Anybody have any advice on where and how to buy the two part ?

I have been snagging it at half price at Boaters World, but I think that ship has sailed.
 
JetSled

JetSled

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Apr 18, 2009
Messages
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Re: Flotation Foam Opinion?

When I foamed the floor of my 22' Sea Ray, I called a polyurethane foam company. They drove a truck out to my boat, drilled 1/4 inch holes in the floor, and pumped the 2 part foam in. It is the same foam they use on hot tubs... and reportedly absorbs 2% water max. It is not like the old open cell foam which I tore out.. completely waterlogged sponge.

They can spray or fill. 15 years ago it cost me $100. Probably 3 times that now.

Great stuff! It stiffened the hull a lot, no creaking over the big swells! ;)
 
redfury

redfury

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Re: Flotation Foam Opinion?

Mark42 said:
If you put it back, follow the Coast Guard recommendation and put it above the deck, not below with the stringers. Has nothing to do with preventing rot. What putting the foam above the deck does is keep the boat from flipping over like it did on the guys in Florida. The boat might be swamped, but you are at least not fighting to hang on.

The entire underside of the gunnels can be filled, either by pouring, or by inserting rigid boards.
Click to expand...

I was thinking the same thing, but Glastron put foam under there, and I had it under the floor as well as two huge pods of it on either side of the boat.

How about an airbag system that can be deployed? :D
 
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