Foam...water-logged foam...and no foam...Let's talk

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richg99

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Foam...water-logged foam...and no foam

There have been numerous posts recently on using foam; using too little/too much foam; taking foam out and not replacing it, etc. I just thought it would be worthwhile to have a round-table discussion on all of that.

As has been clearly stated here before...most recently by JasonLester..foam doesn't float a boat...only displacement i.e. area of hull vs weight of boat and gear............ floats a boat.
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I will simply start it off with my opinion...remembering that it only my opinion and I don't have any formal training in the topic at all.
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No foam..Water, sooner or later, gets in. Water weighs 8 lbs or so a gallon. Water sinks boat or makes the boat so unstable that it turns over and dumps boater and gear over-board.

Foam NOT water-logged. Water gets in. Water fills open areas but cannot fill the area(s) that the good foam is in, so the boat continues to float as too little water is allowed to accumulate in the open areas to sink the boat.

Foam..Water-logged foam. Obviously not as good as "good foam"....but...still does SOME good as the water cannot fill every possible crevice in the foam...so...the water that is allowed in is still less than the amount that would come in if there was no foam there at all.
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IMHO....No boat starts out with water-logged foam. Most water-logged foam situations occur due to poor installation of deck fastened objects and bulk-heads. No caulking on screws; no caulking on bulkheads; boat is left out in the rain; drain is plugged...all the water that sits on the deck, sooner or later, drips down into the foam...and....Viola! we have water-logged foam.

Not the foam's fault. Poor installation and poorer maintenance is the issue.
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You guys take it from here.....
Rich
 
The problem is, the most cost-effective foam is the 'pink'; 'blue'; or 'green' foam boards used for insulation that are about $25 a sheet used for home insulation. That insulation is not a closed-cell foam, meaning it will absorb water.

Simply put, purchase closed-cell foam, like styrofoam or pool noodles, and it will not become water-logged. My local Lowes sells 4x8x2" sheets of a white closed cell foam board for about $26 a sheet--so for me, its a no-brainer, i'm going with that. If I didn't have that option, I would go to a dollar store and buy 50ish pool noodles...

I would not use foam that is not closed-cell... it can and will absorb water--once it does, its effectively doing more harm then good.
 
I think some people are a little overzealous about foam. Maybe they see jon boats sinking every week where they fish...me, I've never seen anyone sink one. But "better safe than sorry" is a good rule to follow. I didn't put foam under my flooring because sometimes I get lots of blood in my boat from bowfishing, I want to be able to flush the bildge. I also did not replace the foam that I removed from my middle seat and instead used it for storage space. The risk of sinking a boat in the waters I fish are nil.

Water logged foam is not better than no foam, in my opinion. I would say water logged foam is more a danger than no foam. False sense of security, decreased performance and handling.
 
Good point about cost....cost can always be a factor. Probably not too many multi-millionaires are here re-doing their tin boats.

I have heard, but have NOT tried proving it...that a coat or two of good outside latex paint applied to any foam can prevent, or at least, slow down, water intrusion. Latex paint is used, rather than oil-based, since many oil-based products will simply melt the foam!

That would be a good experiment, especially for some of our still land-locked Frozen North members to try. Put a square of non-protected open-cell foam...AND..an equal square of painted open-cell foam under a brick in a bucket of water. Weigh both of them after a month or two. I'd like to see the outcome of that experiment.

As far as "more harm than good"...still just my humble opinion..that water-logged foam is still better than no foam...assuming water gets in and floods the boat. Of course, a case can be made that the water in the water-logged foam weighs a lot ( it does) and adds to the over loading.

Back when I was involved with the Carolina Skiff group..a number of us ( me included) had to drill holes in our transoms; tip the boat up on its stern...and let water drip out of the intruded foam for a couple of weeks. As I have said before, most of those issues were not caused by the foam itself, nor by the manufacturer...but rather by poor installation and maintenance after construction and delivery.

Rich
R
 
Foam or No Foam? Foam. I don't want to loose the boat, regardless of the depth. If your boat can plane, it is fast enough to hit an object that can tear a hole in it.

Closed or Open Cell Foam? Closed Cell Foam. Open cell is called a sponge.

Replace Removed Foam? Yes, add more if you can and you added decks or additional non-boyant weight.

Water-Logged Foam? Remove it. Closed cell should not absorb water. Deteriation and long water exposure can lead to it. Try to provide drainage under the foam. I don't like the pour in type, because it becomes a dam. Outside of handling problems, watre-logged foam has lost its boyancy, ie the air cells that provided the boyancy are filled with water.


I have blue styrofoam. I believe it is closed call foam that is used on exterior of concrete. What classification or rating should it have to verify that it is? I have submerged it in a glass of water for weeks, with no weight increase.
 
richg99 said:
Back when I was involved with the Carolina Skiff group..a number of us ( me included) had to drill holes in our transoms; tip the boat up on its stern...and let water drip out of the intruded foam for a couple of weeks. As I have said before, most of those issues were not caused by the foam itself, nor by the manufacturer...but rather by poor installation and maintenance after construction and delivery.

x2. I had to drill holes in my J16 too. Running stringers port to starboard without having any way to let the water drain is genius! And they are still building the boats this way. " They are completely enclosed and water cannot get inside " & " I've only heard of one or two boats that became water logged in my 10yrs of selling".

Okay, They are kit boats right? So when bench seats, Pedestals, Consoles, etc are installed. Aka, one screw hole in floor the entire section is compromised with no way to drain out the water unless you want to tip the boat sideways and drill small holes in the floor for each section. So strip hull bare, reinstall ea piece using truck load of 5200, and then re glass holes. Or ride the water logged dog.

My boat must have gained 100lbs since Mfg'r. ARGH!
 
The only purpose to foam is to provide flotation in a worse-case scenario. If it's relative gravity (weight vs. weight of water) increases to the point where it will no longer float the boat because it is water-logged, then it is no longer doing its one and only job.

If foam is no longer doing its job, it is worse then not having anything for several reasons. First, it increases weight, and drag--making the boat sit lower in the water. This can cause several problems: from as minimal as poorer fuel economy, to actually making your boat more susceptible to capsizing/sinking. Secondly, it can give you a false sense of security. If you believe your boat will not sink, you may not act as fast when it starts sinking. Third, trapped moisture will promote things like fungus growth; mold; and wood rotting--all things which are bad for your boat, and for you.


Just get closed cell foam, its really not that much more expensive, and not that much harder to find.
 
All you Navy guys can attest to this: All boats displace water. Added foam is mainly for safety reasons, thus a coast guard rating for each vessel. Each boat hull can only displace so much water before it sinks, so foam is added for safety, some boats have more than others. The most important thing in my opinion is proper de-watering devices. Foam being the first followed by bilge pumps and lastly a good ole bucket. I put alot of thought into my boat and for now have decided to not put the foam under my deck. I fish waters that are mostly less than 6 feet. Even though I might travel across waters that are up to 50 feet, I still have my life-jacket in a worse scenario. I might add foam in the future but for my purposes it does not warrant the cost for the two part stuff. There is no foam on an aircraft carrier....it all comes down to water tight integrity and de-watering devices. Just my two cents though.

Proud to be a Navy Veteran.
Kevin
 
Does anyone on here have a personal story of foam actually keeping their boat from sinking? Have you ever even HEARD of an aluminum boat that was saved from sinking by its foam?

I've been in aluminum boats all my life. Big ones, little ones, good ones, crappy ones, leaky ones, dry ones .... I've never ever seen or even come close to a situation where foam was needed. I HAVE been in boats with about 4 inches of water on the floor though .... they were still floating just fine.

I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

Now, with all that said, I'm certainly not going to go out of my way to remove it from my boats (unless its water logged). But when re-doing tins, I don't add any additional foam and I doubt I ever will.

But, I also use canoes a lot and I will NEVER be in one that doesn't have foam blocks at both ends .... they have saved my butt on three different occasions.
 
MrSimon said:
Does anyone on here have a personal story of foam actually keeping their boat from sinking? Have you ever even HEARD of an aluminum boat that was saved from sinking by its foam?

I've been in aluminum boats all my life. Big ones, little ones, good ones, crappy ones, leaky ones, dry ones .... I've never ever seen or even come close to a situation where foam was needed. I HAVE been in boats with about 4 inches of water on the floor though .... they were still floating just fine.

I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

Now, with all that said, I'm certainly not going to go out of my way to remove it from my boats (unless its water logged). But when re-doing tins, I don't add any additional foam and I doubt I ever will.

But, I also use canoes a lot and I will NEVER be in one that doesn't have foam blocks at both ends .... they have saved my butt on three different occasions.


I have never needed my air bag or numerous other safety features. ;) I am not sure what year it was required to have mfg have foam in small boats, but think they would have baulked if there wasn't any documented cases. Myself, won't tempt Murphy that much!
 
MrSimon said:
I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

As long as that weight is within the max load value on the Coast Guard's plate, yes, it would keep it afloat.
 
Bigkat650 said:
The problem is, the most cost-effective foam is the 'pink'; 'blue'; or 'green' foam boards used for insulation that are about $25 a sheet used for home insulation. That insulation is not a closed-cell foam, meaning it will absorb water.


Uh, oh. That's what I have in my jetboat, the 1 1/2" thick pink extruded styrofoam panels. I thought it was waterproof, that was why I used it. #-o

Well, I reckon one of these days, I may have to pull that inner hull out, and replace that foam.
 
dyeguy1212 said:
MrSimon said:
I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

As long as that weight is within the max load value on the Coast Guard's plate, yes, it would keep it afloat.


It's all relative... Search 'Specific gravity' either on this board or google, or click here: https://en.wikipedia.org/wiki/Specific_gravity

I have flipped my canoe dozens of times, and the only reason in floated was because of the foam...

If you want to figure out what raw materials comprise your boat, you can calculate how much negative buoyancy you need to float--i.e. how much of the raw material weight has to accounted for in order to keep the boat neutrally buoyant, so it does not sink. It takes some math in order to determine the answer, and I calculated roughly what I needed--then added about 40% more to make sure I was set. Overkill is always the answer.
 
I think foam is better then no foam and yes it's only there incase of taking on water fast were your pumps won't keep up or stop working. JMO but the more safety items you have while on the water the better. I normally have a guest or two with me and their safety is my first concern.
 
Bigkat650 said:
The problem is, the most cost-effective foam is the 'pink'; 'blue'; or 'green' foam boards used for insulation that are about $25 a sheet used for home insulation. That insulation is not a closed-cell foam, meaning it will absorb water.

Seems like that depends on who you ask:

https://www.tinboats.net/forum/viewtopic.php?f=3&t=12567&hilit=blue+board+foam+closed+cell

I used the blue board in my boat, but would like a definitive answer if it is closed or open cell.
 
So moral of the story.. use the stuff that is made for the job.

I understand this site is partially devoted to jerry-rigging, but why not do it right the first time, and save yourself time and money down the road?

Even if you plan on selling it, doing it the right way can help make the sale. I can't count how many tinboats I've called on from CL and asked what kind of wood they used for the decks or new bunks. When they say pressure treated from HD or Lowes, I say thanks for your time.

You never know when you'll run into a buyer that will walk when you say there's X kind of foam under the decks.

Use the two part stuff made for boats, and avoid the headache.
 
MrSimon said:
Does anyone on here have a personal story of foam actually keeping their boat from sinking? Have you ever even HEARD of an aluminum boat that was saved from sinking by its foam?

I've been in aluminum boats all my life. Big ones, little ones, good ones, crappy ones, leaky ones, dry ones .... I've never ever seen or even come close to a situation where foam was needed. I HAVE been in boats with about 4 inches of water on the floor though .... they were still floating just fine.

I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

Yes, actually there was a story just recently with pictures of some folks on one of the great lakes that got swamped.

Four inches of water is not enough to sink a boat...unless it was way over the max capacity maybe...

Their isn't an argument of wether the foam will keep a boat from sinking if it's swamped...and yes some foam under the bench seats will really keep it floating, that's what it is designed to do.

It shouldn't give you all that much confidence...it is a help in an emergency. I don't have that much confidence in an air bag saving my life that I would drive like a fool and I don't have enough faith in foam that I would drive my boat like a fool, or skip on a bilge pump. I don't have enough faith in a bilge pump that I would skip on a manual pump...

That said I don't have any foam in my boat...I am willing to risk it for now but will put it in when I get the chance.
 
It's not that hard to find out, just research the company they are getting it from. This is going to vary from state to stare. When I was in New Brunswick, Canada our HD carried pink stuff that was closed cell. The vendors actually did presentations at shows I had been at where they proved it was water and flame resistant.
 
MrSimon said:
Does anyone on here have a personal story of foam actually keeping their boat from sinking? Have you ever even HEARD of an aluminum boat that was saved from sinking by its foam?

I've been in aluminum boats all my life. Big ones, little ones, good ones, crappy ones, leaky ones, dry ones .... I've never ever seen or even come close to a situation where foam was needed. I HAVE been in boats with about 4 inches of water on the floor though .... they were still floating just fine.

I've also often wondered, with a 140 pound outboard, 150 pounds of batteries, 50 pounds of gasoline, and 100 pounds of gear .... would some foam under the bench seats really keep that boat floating? I don't know, maybe it would .... but it doesn't really give me that much confidence.

Now, with all that said, I'm certainly not going to go out of my way to remove it from my boats (unless its water logged). But when re-doing tins, I don't add any additional foam and I doubt I ever will.

But, I also use canoes a lot and I will NEVER be in one that doesn't have foam blocks at both ends .... they have saved my butt on three different occasions.

Yes. #-o While on vacation (fishing of course) my wife and I came in from fishing in the morning and tied our Polar Kraft 168 SC up to the pier. My wife was the last one out of the boat and I asked her to turn off the livewell pump (500GPH), something that I normally did. The pump was controlled by a 3 way rocker switch. Manual, Off, Auto. She went past Off and switched it to manual. We then let for town to get more supplies and were gone 2 1/2 hours. When we got back I noticed that something really looked strange about the boat, ran out to the pier and there was water almost up to the casting decks. The batteries were submerged, but the powerhead on our 90hp Yamaha was still above water, which was 6' deep. It took me a minute to figure out what was going on.It took a
couple of hours for for the 500 GPH bilge pump to empty the boat. (Yes it did run with the battery submerged). After the boat was pumped out everything worked and we were still married :LOL2: and good to go. As far as I'm concerned foam saved what could have been a ruined vacation and some expensive repairs. Our current boat has all the factory foam.
 

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