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

[kfa4303]

Also, not all "foams" are equal, or to be used in a boat. For marine applications, you only want to use closed-cell foam, but NEVER white styrofoam, which is what most older boats were made with unfortunately. The older foams used can/do soak up tons of water which sort of defeats its purpose. Most DIY folks use the 1" thick pink/blue insulation foam panels from Lowes/HD which works very well and can be removed in the future, unlike spray-in foams that expand when applied and can actually damage the hull and are a PITA to remove should you ever need to repair the hull in the future. Any holes in the hull should be properly sealed by welding them, or filling them with epoxy.

 

[FerrisBueller]

Plain and simple, buy the 1" or so foam sheets from HD or Lowes and cut it to fit.

The foam is there to stop your boat from sinking to the bottom once you have already capsized or taken on too much water to bail out.

I think at that point you have more issues to worry about than what foam you used, in my opinion.

If you take it out when modifying, try your best to replace it somewhere as much as possible, under flooring is a common spot. Probably more times that not we take out more than we put back, but I think there's some wiggle room, and more importantly we need to make sure we don't put ourselves in situations that would put the foam to the test.

 

[RiverBottomOutdoors]

How much foam do you need: None if you don't sink it.

 

[thill]

If you have ever been caught in a sudden squall and have your aluminum boat get swamped (as I have) you will find that it is a terrifying experience. I grew up in the water, and am a surfer, and am not afraid of water in any way, but it was still terrifying.

This happened on a lake, under sunny blue skies. Suddenly, the wind started howling, and we headed back immediately. As we neared the shore, the waves bouncing off the seawalls made for a confused sea, maybe 4' high, and VERY close together. One, two three, and we were underwater. Just like that.

It happens so fast that it's hard to describe, but three quick waves, and the boat was down. Fortunately, there was enough foam in the boat that the nose of it stayed up, and we lost all gear, but were able to retrieve the boat. We survived that crazy washing machine, but it was scary.

My recommendation to EVERYONE, is that if you can, stuff every dead-air space you can with pink or blue foam. It's cheap, light and may save your life, especially if the water is colder than 60 degrees.

I've even seen guys put a bunch of milk jugs and soda bottles in dead space, duct taped together. Whatever!

But either way, if you haven't already, stop whining, and being cheap, and add some potentially life-saving flotation to your boat! Anyone's life is worth that much. How much would you spend for a doctor's visit for something not even life-threatening? I'm sure some floatation would cost only a fraction of that.

-TH

 

[txnman69]

thanks thill,
I agree, my buddy and I caught a "rouge wave" from a very inconsiderate wake board boat last summer that made us both "s*** a brick", we took on water but stayed afloat (thanks to the foam, and THIS FORUM, and many thanks to this website for the help)

 

[thill]

kfa4303 » 23 Sep 2013, 09:10[/url]"]...NEVER white styrofoam, which is what most older boats were made with unfortunately. The older foams used can/do soak up tons of water which sort of defeats its purpose...

Interestingly, I've never seen any of the white styrofoam get waterlogged. I've seen it turn into a million little pills, which is annoying, but never waterlogged. I recently pulled apart an old Glassmaster boat, and under the floor were long sticks of foam sitting loose- dry as could be.

Pour-in foam, on the other hand, just as often as not is completely FILLED with water.

-TH

 

[JimInMichigan]

Doesnt the foam board used as building material dissolve in gasoline?

FEDERAL LAW

183.114 Test of flotation materials.

(a) Vapor test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed in a fully saturated gasoline vapor atmosphere for 30 days at a minimum temperature of 38 deg. C.

(b) 24-hour gasoline test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in reference fuel B, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(c) 30-day gasoline test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in reference fuel B, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(d) 24-hour oil test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in reference oil No. 2, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(e) 30-day oil test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in reference oil No. 2, of ASTM D 471 (incorporated by reference, see Sec. 183.5).

(f) 24-hour bilge cleaner test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 24 hours at 23 plus or minus 2 deg.C in a 5-percent solution of trisodium phosphate in water.

(g) 30-day bilge cleaner test. The flotation material must not reduce in buoyant force more than 5 percent after being immersed for 30 days at 23 plus or minus 2 deg.C in a 5-percent solution of trisodium phosphate in water.

And

Table 183.114 - Flotation Performance Tests

NOTES:
1.The change in volume and buoyancy is measured in accordance with ASTM D-2842. The maxi mum size of a test sample shall be 6" x 6" x 3" and cut by the same method used to shape it for use in the boat.
2.Flotation material does not have to be gasoline, oil, gasoline vapor or trisodium solution-resistant if:


a. Used in manually propelled boats;

b. Installed outside the engine compartment more than 4 inches above the lowest point where liquid can collect when the boat is in its static floating position; or

c. Enclosed or encased in an enclosure that permits no more than one-quarter ounce of fresh water per hour to enter when the enclosure is submerged to a depth of 12 inches.

So if I am understanding this correctly, the building material type foam board can be used, but must be 4" above the lowest point of the boat. Giving I have 9" - 11" deep seat wells on my row boat, I could get some material in there, but not sure I'd meet the standards required by law.

So what do us old boat owners do ( mine is a late 60's/early 70's boat )?

 

[rabbit]

Building foam, pink, blue or white is probably styrofoam. Some building foam and spray in is poly isocyanurate which I don't think is marine rated. Marine foam is urethane. Gasoline will melt styrofoam in a heartbeat. Just a bit of gasoline will melt a whole lot of foam. Don't use it. Use the proper marine rated product. Yea it's too expensive but when you add up all the money you're going to spend on the boat and the cost of possible funerals, it's cheap.
Try how much styrofoam you can melt in an ounce of gas and let us know. It's going to be a lot.
Never skimp on safety.

 

[slick]

Can a person that removes the foam from benches weld an airtight box in their bench? Does it need to be replaced with foam? Is it possible to remove the bench, allow for batteries or whatever and weld the rest of it, then re-install the bench in the boat. These were thoughts in the back of my mind as I read the posts.

 

[thill]

Even if the foam doesn't meet the requirements listed above, it is allowable 4" off the lowest point on the floor. So filling your benches with foam is still do-able.

In a boat I recently took apart, the styrofoam was wrapped tightly in what appeared to be Saran-wrap. It was an old boat, and it looked original. I wonder if that wrapping was to make it water and gas-proof, according to the guidelines posted above?

Whatever the case, it was NOT waterlogged, was NOT all disintegrated into little balls, and was obviously still very buoyant A great idea, in my opinion.

-TH

 

[DaleH]

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 :shock: !

 

[ThatBoyFletch]

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]

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]

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

 

[ThatBoyFletch]

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

 

[Y_J]

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]

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]

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]

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

Sent from my QTAQZ3 using Tapatalk

 

[bobberboy]

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 :shock: !

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. :mrgreen: Imagine it all going to the bottom.

Be safe. Be smart.