# Floatation foam



## Copahee Hound (Dec 21, 2017)

Questions for my safety... I tried google and searching threads but couldn't get a clear answer.

Does the foam core of a boat act as any floatation?

I plan on using as much floatation foam as I can in my benches, but I'm not sure it will even be an adequate amount to actually be safe. So how will I know? 

Thanks in advance


----------



## bryson (Jun 22, 2015)

Physically, anything that displaces water (and has a lower density than water) will provide "flotation" if it's submerged. Keep in mind the boat can have all the flotation in the world, and still capsize.

I guess the question to ask is what's the goal, and under what conditions?


----------



## mro (Jan 24, 2018)

I was considering liquid 2 part foam.
Found this when looking into it.

2 pound foam weighs 2 pounds per cubic foot meaning each 2 gallon kit produces 480 pounds of buoyancy. A 2 gallon kit (1 gallon of part A and 1 gallon of part B) will yield up to 8 cubic feet of cured foam. (looks like 60 pounds of buoyancy per cubic foot minus the weight of the foam.

Note:
the 2 pound foam is not the foam weight used for structural applications.

I've decided to just replace the old beat up Styrofoam under my deck.


----------



## Copahee Hound (Dec 21, 2017)

bryson said:


> Physically, anything that displaces water (and has a lower density than water) will provide "flotation" if it's submerged. Keep in mind the boat can have all the flotation in the world, and still capsize.
> 
> I guess the question to ask is what's the goal, and under what conditions?


Well, I guess I might be overthinking it then... So I'll just add what I can. I think the goal would be to have enough time to grab a life vest and dry box and swim to the bank


----------



## DuckNut (Apr 3, 2009)

Calculate the amount you need. If you have 2 benches in a jon boat style then you probably have enough.


----------



## firecat1981 (Nov 27, 2007)

Copahee Hound said:


> Questions for my safety... I tried google and searching threads but couldn't get a clear answer.
> 
> Does the foam core of a boat act as any floatation?
> 
> ...


Yes, but not enough. A cubic ft of water weighs roughly 62lbs. Many builders use a 5lbs density foam, so each cubic foot (12" × 12" x 12") should in theory float 57lbs when submerged. There are some efficiency losses due to other factors like resin saturation and what not....


----------



## Copahee Hound (Dec 21, 2017)

Thanks guys. With it being a gladesmen with 2 benches, I'm figuring to roughly have +/- 4 cu/ft of foam. So in a perfect world, that gives me 228lbs of floatation plus whatever the foam core would equate to, so it may actually be pretty close


----------



## Copahee Hound (Dec 21, 2017)

Sorry to bring this up again









Stole this from @WhiteDog70810 build from a few years ago. Since I have a good amount of 1" PVC 4 lb density carbon core foam left over, can I use that instead of waiting for Covid to end to go buy some 2 part floatation? If so, would I need to encapsulate it with neat epoxy or glass?


----------



## JC Designs (Apr 5, 2020)

I doesn’t need encapsulated, but will be tough to fit in without leaving voids all over. Will make excellent floatation foam that will not absorb any water!


----------



## Copahee Hound (Dec 21, 2017)

JC Designs said:


> I doesn’t need encapsulated, but will be tough to fit in without leaving voids all over. Will make excellent floatation foam that will not absorb any water!


Thanks again James! Always coming to my rescue


----------



## JC Designs (Apr 5, 2020)

Copahee Hound said:


> Thanks again James! Always coming to my rescue


What I’m here for!


----------



## DuckNut (Apr 3, 2009)

If you suspend the foam you will never have to worry about water soaked foam.

I am going to disagree with JC on this one. If you have a gap between the foam it will not matter as long as the foam is held in place and can not escape and water can be drained if submerged.


----------



## JC Designs (Apr 5, 2020)

DuckNut said:


> If you suspend the foam you will never have to worry about water soaked foam.
> 
> I am going to disagree with JC on this one. If you have a gap between the foam it will not matter as long as the foam is held in place and can not escape and water can be drained if submerged.


I wouldn’t say you disagreed with me. Just maybe a better explanation. Suspending in a few pockets up high while leaving drain holes is a great way to make use and not have to worry about filling in the little gaps! The carbon core/divinycell/corecell/etc... will not absorb water but leaving a drain for condensation to escape the little voids makes it that much better!


----------



## DuckNut (Apr 3, 2009)

JC Designs said:


> I wouldn’t say you disagreed with me. Just maybe a better explanation. Suspending in a few pockets up high while leaving drain holes is a great way to make use and not have to worry about filling in the little gaps! The carbon core/divinycell/corecell/etc... will not absorb water but leaving a drain for condensation to escape the little voids makes it that much better!


If you thought the 2 part foam was expensive, just wait til you start filling up space with carbon core. LOL


----------



## JC Designs (Apr 5, 2020)

DuckNut said:


> If you thought the 2 part foam was expensive, just wait til you start filling up space with carbon core. LOL


It can be, but if he’s got scraps it is a great use of them!


----------



## WhiteDog70810 (May 6, 2008)

Copahee Hound said:


> Sorry to bring this up again
> 
> View attachment 131070
> 
> Stole this from @WhiteDog70810 build from a few years ago. Since I have a good amount of 1" PVC 4 lb density carbon core foam left over, can I use that instead of waiting for Covid to end to go buy some 2 part floatation? If so, would I need to encapsulate it with neat epoxy or glass?


Damn, I figured Photobucket wouldn’t let you see those anymore. It makes my work look so much neater than
it actually was. Because it is closed cell and I suspended it, I didn’t encapsulate it. For what it is worth, that boat lives outside and every piece of foam is still in place going on 7 years later. I’ve never done the math or actually pulled the plug to see if it will float the motor though. I just packed as much foam in as I could and hoped for the best.

Nate


----------



## Shallows (Mar 29, 2020)

Copahee Hound said:


> Well, I guess I might be overthinking it then... So I'll just add what I can. I think the goal would be to have enough time to grab a life vest and dry box and swim to the bank


It doesn't take much; my last two boats were marketed as "unsinkable" foam filled and neither had the bow area filled - only floor - and both were/are mod-v types with pretty shallow floors on top of that. I would personally pour 2-part foam, have done it before and its very slick - yes it can absorb water eventually etc., but nothing is perfect.

As far as safety, when a foam filled boat partially sinks then from what I have seen the bow ends up pointing to the sky (if bow heavily foam filled), or boat capsizes upside down (floor heavily foam filled) and that is the "unsinkable" part - so you'd have to hold onto one of these areas somehow, its not like you can just sit in the boat and chill - they will capsize. I have heard of boats designed smarter with foam only in the sides (rather than floor) so that they stay level and don't capsize, this makes a lot of sense.


----------



## DuckNut (Apr 3, 2009)

Shallows said:


> It doesn't take much; my last two boats were marketed as "unsinkable" foam filled and neither had the bow area filled - only floor - and both were/are mod-v types with pretty shallow floors on top of that. I would personally pour 2-part foam, have done it before and its very slick - yes it can absorb water eventually etc., but nothing is perfect.
> 
> As far as safety, when a foam filled boat partially sinks then from what I have seen the bow ends up pointing to the sky (if bow heavily foam filled), or boat capsizes upside down (floor heavily foam filled) and that is the "unsinkable" part - so you'd have to hold onto one of these areas somehow, its not like you can just sit in the boat and chill - they will capsize. I have heard of boats designed smarter with foam only in the sides (rather than floor) so that they stay level and don't capsize, this makes a lot of sense.


I think there is a lot of misconceptions about the use of foam. Some people think the boat is suppose to float level, some think upright, etc.

What I believe is the premise is that the boat simply does not end up on the bottom giving the Coast Guard a chance to find the boat. Not to mention how much foam would be needed in the stern of a boat to keep a haeavy azz motor from making the stern go under.

But your right a skiff does not need a whole lot to keep it from sinking to the bottom, may not be level but it will be retrievable.


----------



## Copahee Hound (Dec 21, 2017)

DuckNut said:


> I think there is a lot of misconceptions about the use of foam. Some people think the boat is suppose to float level, some think upright, etc.
> 
> What I believe is the premise is that the boat simply does not end up on the bottom giving the Coast Guard a chance to find the boat. Not to mention how much foam would be needed in the stern of a boat to keep a haeavy azz motor from making the stern go under.
> 
> But your right a skiff does not need a whole lot to keep it from sinking to the bottom, may not be level but it will be retrievable.


The very reason I was concerned at first. The deepest water I’ll be crossing is the ICW. Point being, I just need it to float long enough to grab a life jacket, if I’m in deep enough water. Admittedly, I wear a kill switch, but not a pfd. I still can’t imagine this thing sinking with all the foam, but if it does make it to Davey Jones locker, it’s insured. Besides, Charleston is crowded with boat traffic, there will be plenty of people to pick me up and post me on the qualified captain


----------



## JC Designs (Apr 5, 2020)

https://www.uscgboating.org/regulations/assets/builders-handbook/FLOTATION.pdf
It’s all right here. I believe this only applies to builders and you are exempt. But, I am a believer in level flotation for safety purposes.


----------



## Copahee Hound (Dec 21, 2017)

Thanks James! I am technically a canoe, and I’m under 20’ but I am still shoving as much foam as I can, where I can. I did also grab some 2 part foam to supplement any voids


----------



## lemaymiami (Feb 9, 2007)

Remember, if you use two part foam - that a very little goes a long long way... and in enclosed areas can actually move things around by hydraulic pressure if the foam has no where to go as it expands (bulkheads, floors...)... Great fun scooping out expanding foam if you misjudge the amount needed (just another of those "ask me how I know" deals...).

Aren't boats fun?


----------



## Copahee Hound (Dec 21, 2017)

Very little did go a long way. I was able to source some leftover foam from a neighbor, but I’ll have to find a little more to do the same for the front bench. And NO, boats are no longer fun


----------



## lemaymiami (Feb 9, 2007)

No kidding... anyone that works on a boat does need a sense of humor.


----------

