how much foam do I need?

[Johnshan1]

Hey guys I built this boat ive shown the pics before but here it is again just for ref-<br /><br />

<br /><br /><br />I take the boat out in some nasty weather off the coast of maine sometimes while fishing. I worry about taking a wave over someday and sinking the boat as it has no foam in it. Ive been caught in some bad stuff before and im sure I will again.<br /><br />How much foam would I need to make it "unsinkable" if filled with water? I got this info from a kit online:<br /><br /><br />"Each kit (2 gallons total) of mixed Part A and Part B makes 8 cubic feet of foam. <br />A cubic foot of water weighs 62 lbs, the foam weighs 2 lbs, this means each kit produces 480 lbs of buyoancy."<br /><br />So if the contents inside the boat weigh a total of say 600 lbs (including myself and a fishing buddy) I would need to have a little over a 2 gallon kit?<br /><br />Do I need to figure the total weight of everything but the hull, in other words do I need to add the weight of the outboard, gas, battery, basically the total package minus the weight of the hull?<br /><br />Any comments would be great, thanks guys.<br /><br />-John

 

[Realgun]

Re: how much foam do I need?

Basically I think wood floats so your right the hull will not need help however you will need to float the engine and all other hardware. I would guess that 1 kit would be enought for your boat. I used 2 in mine but mines fiberglass.

 

[Johnshan1]

Re: how much foam do I need?

I guess I didnt think of the wood as being able to float, great point I totally forgot about that! Since the hull is 100% wood (along with everything else in the boat) I just need to add up the weight of the cargo, fittings, and motor I suppose then. One kit is 480 lbs, the motor came in the boat at 200 lbs including all controls, cables and gauges, the gas weighs about 60 lbs, battery 40 lbs, that leaves 180 lbs for misc cargo which is problably right.<br /><br />So you must be right- one 2 gallon kit would float the boat if swamped, but if 2 guys were standing in it, thats another story or am I playing to much into this? Thanks for the help!

 

[prockvoan]

Re: how much foam do I need?

If you don't have the space to put the foam in,you can always use 4lb or as much as 8lb weight foam.All you should need is one /2gal kit!

 

[GaCracker]

Re: how much foam do I need?

gasoline is lighter than water. It adds flotation.<br /><br />Ditto the empty gas tank.<br /><br />Ditto the cooler if it's permanently attached.<br /><br />The hull probably has positive flotation.<br /><br />480 lbs. will probably do it.

 

[Realgun]

Re: how much foam do I need?

If you don't have the space to put the foam in,you can always use 4lb or as much as 8lb weight foam.All you should need is one /2gal kit!<br />

NO NO NO<br />Water is about 65 LBS per cibic foot. 2 lb foam is 2 pounds a square foot so you get 63 pounds of lift so the speak. 4 pound foam will only lift 61 pounds of water and in the 4 pound kit you get half the amout of foam.<br /><br />2lbs= 8sq. ft.<br />4lbs= 4sq. ft.

 

[prockvoan]

Re: how much foam do I need?

Even if the boat has all the floation in it that would be needed to keep it afloat with a 1,000 lbs weight,what happens is,there is a very good chance that the boat if it were to sink,it would flip over.That is why the USCG states that a non work boat and boats upder 26' has to have floation to keep the boat afloat up to the surface of water.Wave action would in fact flip a half sunk boat,not as much as one at the surface level.<br />Still,thats a very nice looking boat.I don't have what it takes to build or own a wooden boat again.Been there did that!They are nice,just to much up keep!

 

[Realgun]

Re: how much foam do I need?

And I forgot the 8lbs= 2 sq. ft.

 

[Realgun]

Re: how much foam do I need?

On my Bayliner they put foam in the front, under the consoles front middle (2), and rear (2).<br /><br />In looking at your boat i would put 2 cubic ft in front and 4 under the seat if possible. mayber 2 under console?

 

[MrBill]

Re: how much foam do I need?

I try never to respond if I can't offer help or a reasonable opinion. In your case I can't really help...but had to respond to let you know that you created a beautiful craft. It is truly spectacular...best of luck...enjoy.

 

[Terry H]

Re: how much foam do I need?

I did the math to the USCG specs last year on a boat I built similar to yours, only with a larger motor, and came up with 6 cubic feet of foam. To my way of thinking I would just use as much foam as there is practical space for. Chief