Had info & lost it: How much rigid foam needed?

[lakelover]

I want to use the rigid pink or blue foam for flotation under the floor and in the bow under the deck of my 64 Starcraft. I had info on how to figure how much was required, but managed to lose my notes & calculations as well as where I got the info. I figured out this morning that I have easy room for about 56 cu. ft., but no idea how much I need.

I've searched thru the board and haven't had any luck looking for the info I need. Anyone have a quick link or formula available?

Thanks.

 

[henrye718]

Re: Had info & lost it: How much rigid foam needed?

I have no idea how you calculate or if you even can since your using house siding foam anyway. If cost is not to bad just fill everywhere it can go and dont think about it. If the boat were to ever swamp and stays afloat filled with water then it was worth putting in as much as possible.

 

[lakelover]

Re: Had info & lost it: How much rigid foam needed?

I have no idea how you calculate or if you even can since your using house siding foam anyway. If cost is not to bad just fill everywhere it can go and dont think about it. If the boat were to ever swamp and stays afloat filled with water then it was worth putting in as much as possible.

Thanks. I had somewhere come up with the density of the siding foam and some sort of formula, but darned if I can find it now. I recall when I figured it, it was not easy to find the info. I thought I had bookmarked it, but....

Even though we always wear pfd's in the boat, my thought is that you can't be too careful in the middle of the lake. In the end, it's hard to breathe water.

 

[oops!]

Re: Had info & lost it: How much rigid foam needed?

the foam calculations you are after are in the uscg rules sticky on the afqs page....its the rules for the boat building dection......

but forget it... even tho it will approx tell you how many cubic feet you need.....you cant caoculate the amount of cubic feet with that foam.....

your under deck space is not a constant....it goes with the shape of the hull....so .....as said.....just fill every bit of space with the stuff.....

but mannnn...... that stuff is really expencive.....50 bucks for a 4x6 sheet here.
i scabbed mine from construction sites....but the 15 hours i spent driving around looking for the stuff, didnt justify it self......

 

[lakelover]

Re: Had info & lost it: How much rigid foam needed?

I guess in a practical sense, I don't want to know how much I need so I know how much to put in, but if what I put in will be adequate...I plan to put in all I can but just wonder how close it will be to what's actually needed.

Thanks for helping me reframe the question.

 

[oops!]

Re: Had info & lost it: How much rigid foam needed?

here is the link to the uscg rules.....

check the index for the flotation section.

http://forums.iboats.com/showthread.php?t=191283

there is a way you can get a bit more space using the rigid foam....

put the foam under your cap....( stick the stuff up any where that it can go.,....in the side rails....there is uasually 6-8 inches of waisted space.

and up under the deck in the bow....(unless its a cuddy).....if you do sink.....the foam under the cap will not allow the boat to capsize like foam under the main deck will.....you can actually increase your qubic footage of foam area.....and not have very much or any under the floor.

cheers
oops