the truth about noodles

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Okay,

So i'm kinda of tired of reading about should you or shouldn't you use pool noodles. Seems that nobody (or atleast no one i could find using the search has actually figured out how much one would float)

So i did today. I hope this helps those of you who are looking at how much floatation you need.

Step 1 Figure out how much you will need

So what i'm doing is figuring out the negative buouancy of the major components, those being the hull and the engine. These calculations are for salt water, once i have these done i'll add a fresh water coefficient.

Hull Calculation

w =Weight of the Aluminum Hull 1800
sw =Specific weight of AL = 2.6 (In salt water)
pb = Positive Buoyancy of Hull w/sw , 1800/2.6 = 692.3

Now you need to find the negative buoyancy as that is why you need flotation

NB w-pb 1800 - 692.3 = 1107

So now i need enough flotation to float 1107 lbs (hull)


Now i do the same for the driveline


Drive Line

w =Weight of the engine 640
sw =Specific weight of Cast IRon= 7 (In salt water)
pb = Positive Buoyancy of Hull w/sw , 640/7 = 91.5

Now you need to find the negative buoyancy as that is why you need flotation

NB w-pb 640 - 91.5 = 548

Totals
Total Negative Buoyancy (salt water) is 1655 lbs

Now you can compensate for fresh water by adding 2.5% to that number and a safety factor of 1.3%

1655lbs * 2.5% = 41.36

Fresh water buoyancy is 1696.4

with Safety factor

1696.4 * 1.33% = 22.6

tbw =Total buoyancy weight = 1719 lbs


Step 2 : the pool noodle

I rigged up a pool noodle to figure out how much it will float ( using my Wife's work out weights)

I found that 44 inches will float 8lbs. So that is .18 lbs/inch of pool noodle. or 2.16 lbs per / foot (12 inches * .18)

Okay so to build in some more safety lets say it is an even 2lbs per foot. So if i take my calculated boat weight from above

1719lbs / 2 = 859.5 feet of pool noodle. (now i did this as not all pool noodles are the same length.

860 / 5(foot lengths) gives me a grand total of 171.9 Pool noodles to keep my ship afloat.

So like anything, do some math to see if they will work in your boat. If it is pool noodles, pink stuff from Lowes, or poured in foam. If you don't use enough, its just gonna sink.

Tim
 

cc190cc

Petty Officer 2nd Class
Joined
Jan 17, 2010
Messages
198
Re: the truth about noodles

I figured 20 would do it, uh oh.......jkjk, im glad someone figured this out,
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,766
Re: the truth about noodles

I have 72 in mine. So I'm only borderline screwed :p
 

jspano

Senior Chief Petty Officer
Joined
Oct 30, 2009
Messages
790
Re: the truth about noodles

i'm not good at math, but if a 180 lb man can sit on a noodle and float does that mean only 172 lbs of me add to float.. i think your test is fawled. i'm not saying i have a better answer. try tying a bunch of noodle together and placing a sheet of ply over them and add weight and see how much lbs to go to the bottom of a pool
 

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Re: the truth about noodles

i'm not good at math, but if a 180 lb man can sit on a noodle and float does that mean only 172 lbs of me add to float.. i think your test is fawled. i'm not saying i have a better answer. try tying a bunch of noodle together and placing a sheet of ply over them and add weight and see how much lbs to go to the bottom of a pool

Ahh yes, the reality is that the human person is also buoyant. so the pool noodle your sitting on doesn't have to float the entire weight of the person, it only has to make up the delta to keep you from sinking.

T
 

jspano

Senior Chief Petty Officer
Joined
Oct 30, 2009
Messages
790
Re: the truth about noodles

i think the proper way(if any one is that interested) would be to make a noodle out of 2 part foam and put both under the same test and see the comparison. because your test is only on a pool noodle and to be fair all should be equal. make a 2 boxes and fill 1 with any other foam and the other with cut up noodles and run it.

i think Xlbs amount of 2 part foam and Xlbs of pool noodles will be close
 

Boater45

Seaman Apprentice
Joined
Apr 12, 2010
Messages
33
Re: the truth about noodles

Thanks for the calculations!!! But I've been convinced.
 

Jeep Man

Commander
Joined
Oct 17, 2008
Messages
2,803
Re: the truth about noodles

Timfives, you have way too much time on your hands. You need a hobby.:D
Good info. Most guys recommend blue or pink foam insulation or the 2 part pour-in. Using your calculations, would 1 1/2 foam be enough to float your boat?
 

Boater45

Seaman Apprentice
Joined
Apr 12, 2010
Messages
33
Re: the truth about noodles

i think the proper way(if any one is that interested) would be to make a noodle out of 2 part foam and put both under the same test and see the comparison. because your test is only on a pool noodle and to be fair all should be equal. make a 2 boxes and fill 1 with any other foam and the other with cut up noodles and run it.

i think Xlbs amount of 2 part foam and Xlbs of pool noodles will be close

I'm up for that challenge.....I think the foam will be the clear winner.;)
 

bananaboater

Ensign
Joined
Jul 27, 2009
Messages
932
Re: the truth about noodles

One thing to consider is that the noodles are round and when placed in the bilge they leave considerable empty voids. If you cut foam to fit the space tightly that will increase the buoyancy. Or if you cut the noodles to fill the space that would help. In the end whatever you do, it will be better than the styrofoam original to many of our boats.

Albert
 

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Re: the truth about noodles

i think the proper way(if any one is that interested) would be to make a noodle out of 2 part foam and put both under the same test and see the comparison. because your test is only on a pool noodle and to be fair all should be equal. make a 2 boxes and fill 1 with any other foam and the other with cut up noodles and run it.

i think Xlbs amount of 2 part foam and Xlbs of pool noodles will be close

Actually this has nothing to do with poured in foam. If you wanted figure out how much poured in foam to use then you have to calculate that, generally found by a flotation factor divided into the weight of the object to be floated.

You have to know what your floating, and the type of floatation your using, different types of flotation would require different amounts.

T
 

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Re: the truth about noodles

One thing to consider is that the noodles are round and when placed in the bilge they leave considerable empty voids. If you cut foam to fit the space tightly that will increase the buoyancy. Or if you cut the noodles to fill the space that would help. In the end whatever you do, it will be better than the styrofoam original to many of our boats.

Albert

Great Point cutting them down to eliminate the void would increase the overall amount you could get in a boat, and thus increase your floatation.

T
 

jspano

Senior Chief Petty Officer
Joined
Oct 30, 2009
Messages
790
Re: the truth about noodles

i would love to do the test but i have no 2 part foam and can not get any sheets here. just remember to be scientific all things must be equal and as stated noodle have voids so lbs would be my way of thinking 10 lbs of each and the same test
 

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Re: the truth about noodles

1 cubic foot of foam will float 62 lbs +/-

Glad you spent all the time ....... it has been done already both here http://forums.iboats.com/showthread.php?t=288451 and on the Simpsons :eek: :D

Bob, I'm not advocating one way or another, i just didn't find any post for how much buoyancy was in a pool noodle. Just thought it would help those considering it, and give an idea on how to calculate your boats weight based on the specific gravity of its main components.

To your comment, what type of foam will float 62lbs? Not all foam is created equal, is that referring to the pink stuff you get at HD?

Many thanks

Tim
 

timfives

Petty Officer 1st Class
Joined
Jul 30, 2009
Messages
382
Re: the truth about noodles

Timfives, you have way too much time on your hands. You need a hobby.:D
Good info. Most guys recommend blue or pink foam insulation or the 2 part pour-in. Using your calculations, would 1 1/2 foam be enough to float your boat?

Thanks, all the pool noodle discussion got me thinking thats all :D

Given i took all the poured in foam out of my boat during the restoration, i've seen first hand the damage it causes, between the corrosion and the fact that it held water tight agains the wood thus allowing it to rot, i won't be putting it back in.

I'll probably be using the pink stuff, but this was a worthy cause given the state of my restoration.

Thanks!

Tim
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
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May 19, 2001
Messages
25,892
Re: the truth about noodles

Not so....... flotation foam is really really close in buoyancy.

1 cubic foot of pool noodle foam will float the same amount as 1 cu ft of 2 part or 1 cu ft of pink or blue hardware store stuff.

There is a slight variance in the weight of the cubic foot. If 1 cubic foot weighs 1 lb (just as an example) it would float 61 lbs of weight and if it weighed 10 lbs it would float 51 lbs of weight. (the weight of the foam is subtracted)

Pool noodles would have to be figured in cubic inches to figure out the amount of foam remember to subtract if the noodle is hollow ;) So how many pool noodles equal 1728 cubic inches.

1 cubic foot of dry wood will float the same amount of foam but you would still have to subtract the weight........
 
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