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



## Jim

Thanks to Brine for the Link! :beer:

This is a guide for foam in a boat. *This is Federal law for boat builders.* For those that think that they want to rip it out to make room or save weight or whatever.....think twice before doing it. TinBoats.net takes no responsibility with what you do. You are on your own. I recommend you leave it in and or replace what you remove.  

https://www.uscgboating.org/regulations/boatbuilder_s_handbook/flotation_part1_e.aspx


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## Bigkat650

Great link Jim!

Details on what is legally needed; formula's to calculate the foam required; and examples of the formulas in use. Should be a big help to all those looking to replace or install foam, and for those who "don't think its necessary", it specifies this is a legal requirement--meaning God forbid anyone is injured or killed as a result of a boat not have flotation--the owner _might_ be held liable.


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## Dockside85

Wow, pretty crazy when you do the math. A full 8'x4'x.5" sheet of closed cell foam from HD or Lowes is only 1.3 cubic feet of flotation material. That doesn't seem like a lot when removing the foam from 1 bench you take out can be a 3 or 4 cubic foot loss right there! But then again, most of our boats won't need the 25 cubic feet the inboard/outdrive in the example needed!


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## fool4fish1226

Jim said:


> Thanks to Brine for the Link! :beer:
> 
> This is a guide for foam in a boat. *This is Federal law for boat builders.* For those that think that they want to rip it out to make room or save weight or whatever.....think twice before doing it. TinBoats.net takes no responsibility with what you do. You are on your own. I recommend you leave it in and or replace what you remove.
> 
> https://www.uscgboating.org/regulations/boatbuilder_s_handbook/flotation_part1_e.aspx



Jim I hope this ok to post here? Here is a link to the place I purchased my foam (https://www.uscomposites.com/foam.html). I used the 80lb kit (2lb foam) and used almost every bit of it on my build, I think I should be good


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## Dockside85

Man you didn't spare any expense on that 80lb kit! Stuff looks awesome though. I'll try that out on my next build.


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## PSG-1

Thanks for that link. Excellent resource! =D> Very technical, but a little basic math can help determine whether you've got enough foam.

They give an example, although, they give it for a fiberglass boat. That doesn't help those of us with aluminum boats. We need an example for that. So, if y'all don't mind me posting this.....here ya go:



Here's what I came up with for my jetboat, which is a modified 1648 Duracraft. 
DISCLAIMER: This is a rough guess-timate, your particular application may be different, but this should at least give everyone an idea:




Step 1: Determine the flotation needed to support the submerged boat (Fb).
Formula:
Fb =([Wh x K] + [Wd x K]+ .69We ) ÷ B
Where:
Fb = flotation needed Wh = dry weight of hull *(425 lbs for Duracraft 1648)*
Wd = dry weight of deck and superstructure *(75 lbs for flooring, rear deck) *
 We = dry weight of factory installed equipment, hardware and accessories *(50 lbs for console, cables and wires) *

K = conversion factor for material used. See Table 4.1 below B = buoyancy of one cubic foot of flotation material expressed in pounds.

Since the total weight for aluminum is multiplied by .33.....I added up the weight of everything, did the conversion, and arrived at * (284 lbs)*



Step 2: Determine the flotation material needed to support the submerged propulsion equipment (Fp).
Formula:
Fp = G ÷ B
Where:
G = 75% of the installed weight of the engine, drive and battery (inboard), or the engine, outdrive and battery (sterndrive) - in pounds to the nearest whole number;

*(320 lbs total...this accounts for 75% of the weight of the engine, battery, and jet pump)
*

Step 3: Determine the flotation material needed to support the persons capacity (Fc).
Formula:
Fc = .25 (C) ÷ B
Where:
C = Maximum weight capacity. *( 3 persons @ 150 lbs or 450 total)
*
 B = Buoyancy of 1 cu.ft. of flotation material used in pounds.


*(112 lbs total)*



Step 4: Determine the total flotation material needed (F) to support the boat. This is the sum of steps 1, 2, and 3 above.
Formula:
F = Fb + Fp + Fc



So, I added up the *112 lbs* for persons, *320 lbs* for the engine, and the *284 lbs* for the hull, etc...and then divided that total number by 60 (buoyancy of foam per cubic foot) and arrived at a figure of *11.933*...that's the amount of cubic feet of foam required....roughly.


Then, knowing that a 4x8 sheet of 1.5" foamboard is about 3.9 cubic feet, and that my floor is about 4x8, along with the 2 gunwales at roughly 2x8', (totalling up for another 4x8' sheet), that's 2 sheets of foam, or roughly 7.8 cubic feet.

I have another cubic foot of foam in the stern, and then about 2-3 more cubic feet in the bow...for a rough estimate of somewhere between 11 and 12 cubic feet of foam all together.

So, I have the minimal amount required, but at least now after doing the math and figuring it out, I feel a lot better about that boat's seaworthiness! 

Again, thanks for posting that link, definitely clarifies everything.


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## BloodStone

*Well...Considering that my current Aluminum project had zero foam on the floors/sides & I only removed one bench seat (& it only had 3-4 big junks of Styrofoam & the rest pebbles-what a pain in the arse those pebbles are); I think I'll be in fine shape. Especially when I add 1.5" on the floor & 3/4" on the sides & up in front as well. Added up, it is a lot more than what I took out.*


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## tla100

Would the pourable foam help seal up and small leaks ? 

Looks like some sweet stuff.


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## jr1053

Yesterday recovered my completely submerged(tied to dock on one side and the bow) starcraft mariner 180 after I removed the foam and discarded it while replacing the floor last winter. Shining example that foam does serve a purpose. swamped would have been a lot easier to deal with than sunk with the motor 8 feet under water.


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## peabody

im still confused... ive a 16 foot wood boat ... and i need to put foam in it ? its the law ?
i was wanting to keep the boat open.. where to add the foam ?


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## highgeardaddy

Has anyone checked with the contractors who are spraying foam as residential/commercial building insulation to see if they can provide the good closed cell stuff? I guess it really doesnt matter, the price just for the material on that DIY link is outrageous.

Are there any other options? I've had no luck with the foam sheets from HDepot or Lowes. It gets waterlogged quick then your packing around dead weight AND you arent getting any floatation benefit.


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## highgeardaddy

peabody said:


> im still confused... ive a 16 foot wood boat ... and i need to put foam in it ? its the law ?
> i was wanting to keep the boat open.. where to add the foam ?



I'm not an attorney but manufacuturers are (and have been for many years) held to the foam requirements. The information is provided here for reference. Someone in the know would have to advise on the legal stuff.

Note the Black Pearl was made of wood and it went to Davey Jones locker when it was loaded with booty. Its all about weight of water displaced by materials (net bouancy).


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## Action762

Hey Guys,

Ok so I am just curious if it is "required" by law to have floatation in your boat to keep it afloat. Who’s checking? I am looking to modify a 12' V and put a deck on it. There is not much room now as it sits. I was looking to put a low deck and seats with a high, "short", deck for the trl-motor. I have read through the forum posts here and I get it, but who’s checking? If you have floatation in your boat to keep it afloat if sunk great. It makes it easier to retrieve, if not buy some scuba gear and get it off the bottom. I am law enforcement so by no means am I trying to break the law or even bend it. I am just trying to learn because I am new to the whole thing, (i.e. first boat) and would hate to make a mistake and have to fix one like this. Thanks or clarifying if anyone does.


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## txnman69

glad i read this posting section. i'm currently doing a 14' aliminum boat mod. and cut out a section of each of the 3 benches (to put battery in one, onboard cooler/livewell in another and small storage in the other) made carpeted bench tops (middle one lifts up for access) , in doing so i removed ALL the styrofoam.
like other posts i've read here, my boat only had chunks of foam and most were rotted so bad i didn't recognize them as styrofoam.
my idea is to seal off the open sections i've made (for battery...etc) and use the expandable foam in a can from home depot or lowes.
if anyone can let me know , will this be enough floatation ? , what other options are there ? (BUDGET is a HUGE issue  ).
thanks to all for any insight or tips


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## fiberglass

Jim is right about the *manufacture* of the boat has to put foam in a boat that is 21 feet or less. Its uo to you to decide how much foam you want to put back in the boat. I would prbally advise on putting back what you removed. On a aluminum boat what I would do different once I take out the old foam I would coat the aluminum with an epoxy before putting the new foam back in as to prevent the aluminum form oxidizing. No matter what foam you use it if it stays wet long enough it will soak up the water. I know the 2lb foam will typically expand about 20 to 30 times it liquid volume and of coarse that varies due to the humidity. Hope this helps a little. Thanks


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## bassboy1

fiberglass said:


> *No matter what foam you use it if it stays wet long enough it will soak up the water.*



Let's echo this point one more time, as it is commonly misunderstood. Just because a foam is closed cell does not mean it won't soak up water. It most definitely will.


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## txnman69

Thank you fiberglass for your input , any is GREATLY appreciated not only by my self but all im sure


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## apsauce

Anyone else completely confused?? Maybe its just me lol but this whole foam thing has me in a headlock. Getting ready to mod my 12 ft 66 murry jon and this foam situation has smoke coming outta my ears lol.


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## MiPikeGuy

[url=https://www.tinboats.net/forum/viewtopic.php?p=302921#p302921 said:


> apsauce » 03 Mar 2013, 22:33[/url]"]Anyone else completely confused?? Maybe its just me lol but this whole foam thing has me in a headlock. Getting ready to mod my 12 ft 66 murry jon and this foam situation has smoke coming outta my ears lol.



I'm also confused, so you're not alone.


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## txnman69

hey guys, I modified my benches (14ft alumiline I think) made carpeted 3 piece bench tops and cut out the center section of the bench top and removed the foam (still leaving foam on both sides), the center sections of the benches lift up (on a piano hinge) , the front bench is small storage (extra glasses, scale, small baits...etc, ) the center bench contains my battery for trolling motor and fish finder, and the rear bench contains lifejackets,
I did replace all the foam during this process with new foam as the old foam was less than useless. My fishin buddy(not a small guy ) and I have encountered some scary waves for a boat like mine and came out ok ( gotta steer into it before hand !).
I haven't taken pics to post on here but will if it will give some help to those wanting to do the same type of thing. 
hope this helps guys


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## 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.


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## 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.


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## RiverBottomOutdoors

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


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## 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


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## 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)


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## thill

[url=https://www.tinboats.net/forum/viewtopic.php?p=330156#p330156 said:


> 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


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## 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 )?


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## 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.


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## 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.


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## 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


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## 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: !


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## 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?


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## wormil

ThatBoyFletch said:


> 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.


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## safetyfast

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


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## ThatBoyFletch

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


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## Y_J

ThatBoyFletch said:


> 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.


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## 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.


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## 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?


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## 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


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## bobberboy

DaleH said:


> 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.


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## CedarRiverScooter

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.


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## gnappi

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.


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## Johnny

rigid foam board







.


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## gnappi

Excellent, thanks. 

For under deck, any opinion on faced or not?


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## Johnny

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 ~


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## minuteman62-64

I used pool noodles in two side compartments at the stern of my Bayrunner. The three bench seats all still have the original (1982) foam blocks, still in good condition.


The pool noodles were used in the side compartments to allow access when needed (just pull them out - then replace when done). However, because of the holes in the center and the geometry when packing them in, I calculated I only get 1/2 the floatation I would if the compartments were solid with expanding foam. My project list includes doing something more effective, floatation-wise. Plastic bagging the noodles would work, as would some sort of inflatable "bags." Haven't decided yet.


Interesting thing I found out about my boat and floatation. A few years back I saw the tow service bring in an identical Bayrunner, with all factory foam in place. The guy had been offshore (in the Pacific) when hit by a rogue wave and swamped. The way he (owner) described it, the boat immediately flipped (floatation low). Floated great, just upside down


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## CedarRiverScooter

I think you cab get spray-on foam. If you apply it to the undersides of the deck & gunnels, then it may float upright.


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## Pector55

Along with total amount of foam needed for flotation, I just figured out how much Total Boat pour foam to use per rib on each side for when I pour it under my deck. 

You can use a wedge volume calculation to determine it. If you know the height (I have a center beam), then the two lengths (top and bottom) as well as the width of the rib, it can be calculated. In my case 1/2 quart of the mix (1/4 quart of each part) will expand to approximately .5 cubic ft.

I determined that my "wedge" averaged .67 cubic feet but if I lock in 2 pieces of 2" thick x 4" h x 10" long pieces of foam, I can reduce the wedge to .49 cubic ft and in the process, assure the foam does not creep over the center drainage opening between the ribs. 

Here are a couple of online calculators if you want to figure it out on your boat:

Calculate the volume of a wedge in cubic ft: https://keisan.casio.com/exec/system/1322717681
I get 1152 cubic inches 

now convert cubic inches to cubic feet here: https://www.google.com/search?q=convert+cubic+inches+to+cubic+feet&rlz=1C1SQJL_enUS844US844&oq=COnvert+cubic+inch&aqs=chrome.0.0j69i57j0l4.5933j1j7&sourceid=chrome&ie=UTF-8

That cuts me down to .6

Now if you are adding board foam to your wedge, you can cut down on the initial base lengths to get your total cubic feet down to where you need it. The reason I am doing that is that 1, 2 gallon mix of Total foam equals 8 cubic feet of foam. 2 gallons is 8 quarts so 1 quart of mix = 1 cubic foot. 1/2 quart of mix should fill 1 rib / side so I can do a total of 4 ribs with a 2 gallon mix. You get 300lbs of floatation per gallon so I'll get 600 lbs of floatation not even counting the sheet foam. 

I will do 4 ribs (2 in the very back and 1 each where each seat mounts) and use sheet foam on the others.


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## Vader809

If you are using pool noodles, I suggest that you replace them with real marine grade substitute. Pool noodles break down fairly fast. Heat is the issue,especially in a dry environment. They were made to stay wet,and yes they don't hold much water. And seem to float with a heavy load. Pourable foam isn't cheap. But IF you can figure out how much you need, then the cost may not be as expensive.


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## tom q vaxy

does anyone bother with marine grade floatation solid foam?

https://www.generalplastics.com/markets/marine

this seems like the "almost 3m thinsulate" threads in the van conversion forums.

thanks


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## satx78247

minuteman 62-64; EVERYONE.

As I'm about to start restoring the STARCRAFT HOLIDAY 18 & will replace the whole floor & the floatation under it. - What DOES worry me is how to figure out HOW MUCH sheet foam I need to ASSURE that we float "right side UP" if we should get swamped "out on the salt".
(TRUST ME, IF we are out chumming-up large/hungry sharks to measure/tag/release we do NOT want to "go for a swim", should the boat swamp & flip upside down.)
The late/famous boat designer, NELSON SILVIA formerly of Wilmington, NC, used to say that MOST "stock boats" are MORE stable when upside down than the boats ever were when right side up.

Also, my math skills are POOR too.- Thus, I'm hoping the someone will help me figure HOW MUCH pink/blue floatation sheets that we need to install in the sides & under the forward deck to stay right side up, in addition to replacing the water-logged foam that is under the old flooring, should we get swamped by a wave/collision/another hazard.
(I presume that filling up every space under the floors with pink/blue foam, "cut to fit" will BE SUITABLE to replace the "soggy wet stuff".)

yours, tex


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## gogittum

Couple of things I found out the hard way that I haven't seen mentioned in these pages:

I had to put a new floor in my older 19 ft Glastron runabout some years ago and used pour-in 2 part Urethane foam for the job. Going by recommendations at the time, I just used to-go drink cups for mixing - 1 each 16 oz to measure the parts, (to an inch or so below the rim) and a 32 oz to mix and pour with.

I did the floor on a warm, sunny summer day and had pre-cut 4" holes in the plywood floor about 3 ft apart, between the longitudinals. Jacked the front of the trailer as high in the air as I could get it, so's the foam mix would run downhill quickly. Watching that stuff was amazing....like the return of the Blob. Pour the 2 - 16 oz cups into the 32 oz cup, (just pour and go - you won't have time to scrape the cups clean) stir it quickly - you'll see the color change and you'll also see it very quickly start to rise in the cup. You gotta work fast. 

Pour it into the lowest hole, wait a few seconds and you'll see it coming back up like a living thing as it expands. Kinda spooky/comical. I did it this way since I'd been warned that it would put extreme pressure in a closed container - enuf to rip my floor loose. My 32 oz at a time turned out to be right at the limit.....I heard that floor creak a few times but it did hold. I'd kept the hole saw disks and screwed a cross piece to each ahead of time. As the foam reached each hole, I jammed a disk into that hole and screwed it to the deck to keep the foam contained. "It happens fast ! ! !"

The difference in that boat was amazing. Previously, it was very noisy going thru chop, with the stringers slapping the underside of the floor. Now, it was rock solid and rigid and very quiet. I loved it.

As a follow-up, several years later I built a Sam Devlin design duck boat (original Black Brant - excellent design) for a friend and used the same stuff in the bow floatation compartment and in the rear sponsons. I built that boat in the winter in the northwest and it were cold. When I mixed and poured the 1st batch of foam, it didn't do anything. Oh, it did swell up some, but no more than 2 or 3 times its' original volume....not much good for floatation....and that stuff is expensive.

Finally figured out that it was the temperature.....dohhh. For myself when working with the epoxy on the boat, I'd taken a module out of a Kitchen Aid dishwasher that heated the air for drying dishes. (this was in the early '90s) I put that in a window to pick up clean air and it delivered nice warm air. Attached a 20 ft length of portable oxygen hose to it to carry that warm air to my face mask. Next batch, I put that plastic hose down in the hull with warm air blowing thru it to pre-warm the compartment and set the Urethane containers on the baseboard heaters for an hour or so, till they were nice and warm. Then mixed and poured and they acted as the stuff I used in the runabout did.


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## CedarRiverScooter

The dishwasher heater is a great idea! I myself am lucky never to have started a fire . . .


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## gogittum

Thanks. I owned and operated a commercial appliance service (restaurant equipment) at the time and lots of stuff was available to me....and I like to play and invent stuff.


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## zuren

Just FYI to the OP - the link in the first post is dead.


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## Snuffy Smiff

I figure I need just enough to keep my fat arse afloat if the boat goes down... Hopefully, I can then dog paddle to shore


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