*****HOW MUCH FOAM DO I NEED*****

Post by **DaleH** » 03 Mar 2015, 10:54

FWIW I've used that 2-part expanding foam and it is AWESOME stuff.

However, one must be very AWARE that it will pop the fiberglass deck off the stringers if used improperly. I believe the damage would be far worse in a tin boat ... it allowed to expand with no more room to grow ... POP

!

ThatBoyFletch · Post by **ThatBoyFletch** » 26 Jun 2015, 05:24

This topic has me beyond confused now. So instead of using the sheets of styrofoam you can find at hd/lowes, I was going to use pool noodles. Will those soak up water and eventually become useless? I also saw a guy said that they wrapped it in saran wrap to prevent the styrofoam from soaking up water. Would that work?

wormil · Post by **wormil** » 26 Jun 2015, 14:53

ThatBoyFletch wrote:This topic has me beyond confused now. So instead of using the sheets of styrofoam you can find at hd/lowes, I was going to use pool noodles. Will those soak up water and eventually become useless? I also saw a guy said that they wrapped it in saran wrap to prevent the styrofoam from soaking up water. Would that work?

I'm no expert on foam but my neighbor leaves noodles in his pool, never seen one sink. They are made of polyethylene and essentially the same thing as pipe insulation. I think the concern is that pool noodles are cheaply manufactured and if left in contact with water, like in the bottom of your boat, some of that water is going to find it's way into the foam reducing buoyancy. So using them in the bottom is a bad idea.

The other concern is that noodles my provide less buoyancy than Styrofoam or the blue insulating foam. So if you are replacing factory foam with noodles, your boat will be less buoyant if capsized and may sink.

My boat has expanding foam in the bottom and Styrofoam in the inboard bracing, from the manufacturer, but there isn't enough of it that I feel confident it would float. I'm not arguing for or against pool noodles. Clearly they are not a replacement for the proper foam but there may be situations where they are adequate.

If this iboats post is to be believed, noodles will float approximately 2lbs per foot. It doesn't say if he tested hollow or solid noodles. My boat weighs 345 + outboard 159 = 504 lbs. Assuming the average pool noodle is 60" : 504/2/5 = 50.4 pool noodles. On a different forum someone stated that 3' of noodle will float 5lbs., meaning it would take only 20 noodles. On yet another forum a test revealed 2lbs per 1' of noodle. Buoyancy is way more complicated than my simple math but it's a starting point. I think the lesson is that if you do use pool noodles, test one to see how much weight it will hold because not all noodles are the same.

safetyfast · Post by **safetyfast** » 26 Jun 2015, 18:48

I think I'll just leave my life jacket on.

ThatBoyFletch · Post by **ThatBoyFletch** » 26 Jun 2015, 22:26

im not replacing any foam, I am just adding some underneath the flooring I will be doing.

Y_J · Post by **Y_J** » 27 Jun 2015, 21:31

ThatBoyFletch wrote:im not replacing any foam, I am just adding some underneath the flooring I will be doing.

I used the Pink insulation foam under my floor, to make up for what I took out when removing my center bench. Will it be enough to float my boat if swamped? So far I haven't had to find out and hopefully I won't.

mirroman · Post by **mirroman** » 28 Jun 2015, 13:19

I finally found a bunch of dock flotation foam to replace the under seat stuff. What a hard thing to find in my small town America but does make the job 100% easier to deal with.

Stormy Monday · Post by **Stormy Monday** » 15 Oct 2015, 13:29

Long time kayaker here, just starting my tin rebuild. As I was looking at these posts I couldn't help but think about the flotation bags I use in sea kayaks and whitewater canoes for this exact purpose. They float, displace water and are very lightweight (but probably cost more than foam. a 37"x30" center bag weighs 50 oz., costs $75 and floats a swamped canoe pretty well, thinking of putting one aft under the deck I have planned and then some triangular bags from my kayaks forward. Thoughts?

oakchas · Post by **oakchas** » 16 Aug 2016, 20:20

The original link to the U.S.C.G. boat builders handbook on foam has changed to:
https://uscgboating.org/regulations/ass ... TATION.pdf

Sent from my QTAQZ3 using Tapatalk

Post by **bobberboy** » 17 Aug 2016, 08:07

DaleH wrote:FWIW I've used that 2-part expanding foam and it is AWESOME stuff.

However, one must be very AWARE that it will pop the fiberglass deck off the stringers if used improperly. I believe the damage would be far worse in a tin boat ... it allowed to expand with no more room to grow ... POP !

This is no joke. I once worked on a project where we built a form for casting an architectural element out of two-part foam. We used 2x6's on 12" centers over 3/4" plywood anticipating the pressure created by the foam. On the first casting the pressure blew the form apart. We had to go to 8" centers.

Good advice to think a little before tearing apart your boat for modifications. There are two things at work that may not be immediately apparent. One is that the manufacturer for reasons of weight, cost etc. is doing what is necessary to build a safe boat while not doing more than necessary. You only need to look at the number of posts here about removing seats to see this controversy. The seats in many boats are structural, allowing the manufacturer to use smaller ribs or less substantial materials. If you compare the ribs of boats designed to be open with those using seats as structure it's easy to see the difference. Take seats out of a boat that uses them for structure and you're compromising the boat.

The other is the foam. Don't believe for a minute the manufacturer would put it in if the law (and a room full of attorneys) didn't make them. It's there because it's required to keep you safe. And don't believe careful boating can prevent situations that put you in danger. Accidents by definition are unplanned. They can happen to the most careful and experienced operator. Even if you have your life jacket on, imagine floating on the water watching your boat and gear sinking to the bottom. Just the gear alone would quickly add up to hundreds of dollars. There's a reason you don't tell your wife how much you really paid for all that stuff.

Imagine it all going to the bottom.

Be safe. Be smart.

CedarRiverScooter · Post by **CedarRiverScooter** » 17 Aug 2016, 18:30

Good advice Bbb.

Just to reinforce the thought - I was hit by another boat, never thought it could happen to me but it did.

Redundancy is a key element for safety. Extra foam fits in that category.

gnappi · Post by **gnappi** » 12 Aug 2017, 13:56

I looked at the lowes site, and they have a lot of foam building products. Are you folks talking about the foam board, or the rolls? A link would be greatly appreciated.

Post by **Johnny** » 12 Aug 2017, 14:16

rigid foam board

insulation.jpg

Owens.jpg

.

gnappi · Post by **gnappi** » 12 Aug 2017, 14:30

Excellent, thanks.

For under deck, any opinion on faced or not?

Post by **Johnny** » 12 Aug 2017, 15:53

it has a thin plastic sheet laminated to both surfaces as a vapor barrier.
other than than that, there is no facing.
blue is Dow Corning
pink is Owens Corning
~ same thing ~