Floatation Foam

[Lwarden]

Do all fiberglass boats have flotation foam in them?

 

[QC]

Re: Floatation Foam

No. Not required on any boat above 20 ft. Some do though. My 23 footer doesn't have any.

Edit: for clarity. No boat is required to have "foam". Just positive floatation below 20 ft.

 

[stringpincher]

Re: Floatation Foam

I don't mean to hijack this thread, but will the spray insulation work as floatation foam? I've heard of guys using pool noodles, good/bad idea?

 

[QC]

Re: Floatation Foam

Lots of noodle lovers here. I'll wait for someone else to chime in on spray in.

 

[Teamster]

Re: Floatation Foam

The spray stuff in a can found at big box stores is NOT GOOD in a boat, It is open cell foam,...

You will want closed cell foam for floatation in a boat,.....

 

[stringpincher]

Re: Floatation Foam

Thanks, I think noodles is the way i,m going to go, seems to me they would let any water migrate to the bildge better.

 

[jigngrub]

Re: Floatation Foam

Thanks, I think noodles is the way i,m going to go, seems to me they would let any water migrate to the bildge better.

Noodles and EPS sheet foam are for aluminum boats, expanding 2 part urethane foam is for fiberglass boats.

Fiberglass boat manufacturers use expanding foam in their boats for structural support as well as floatation, it supports the hull and deck. Take the expanding foam out of a glass boat and it becomes weak and floppy. The expanding foam is a single solid unit in glass boats while noodles and cut EPS sheets are many individual pieces.

 

[Woodonglass]

Re: Floatation Foam

This ^^^ is not always the case for Glass boats. Some foam IS structural but not all. Depends on the MFG and the design of the boat.

 

[stringpincher]

Re: Floatation Foam

I guess noodels are out, if it add to the structural integerty of my boat, I guess I'll have to foam it,but,in a 14.5 foot fiberglass princecraft, how much expanding foam should I buy?
The stringer in the center is 7 in. and the deck is about 14x5 foot.
Would a quart of this stuff expand enough to fill this area? or is there a online calculator somewhere? And do most marina part stores have it?

 

[jigngrub]

Re: Floatation Foam

Expanding foam is sold in lb. kits that fill an approximate cubic footage.

The exact dimensions of your below deck including all of the tapers are needed to figure your quantity of foam closely.

I did a very rough estimate that came out to about 12 cubic feet.

You can buy the 2 part urethane foam online here:

http://www.uscomposites.com/foam.html

 

[Scott Danforth]

Re: Floatation Foam

I guess noodels are out, if it add to the structural integerty of my boat, I guess I'll have to foam it,but,in a 14.5 foot fiberglass princecraft, how much expanding foam should I buy?
The stringer in the center is 7 in. and the deck is about 14x5 foot.
Would a quart of this stuff expand enough to fill this area? or is there a online calculator somewhere? And do most marina part stores have it?

no, a quart of that will not fill it.

generally the foam is 2# kits (2#/cu ft) for floatation foarm. a gallon of foam is approx 8# of material. if your deck is 14' x 5' and your stringer depth is 7", you have approximately 40 cubic feet of area (assuming square deck and there is no taper to your stringers, etc.) if your stringers and bulkheads taper to nothing, then you may get away with about 20 cubic feet. taking into consideration of your bow taper, you will be closer to 15 cubic feet. the formula for volume of a rectangular opening length x width x height. the volume of a triangular shaped area is length x width x 1/2 height

 

[Georgesalmon]

Re: Floatation Foam

When figuring out how much foam some consideration should be given to the floatation requirements you are trying to achieve. Besides any structural needs that may be required you should also note the weight of the boat and all the other weight you will be adding. As a very rough guide the foam will support about 50 lbs per cubic foot. Its not an easy formula because everything weighs less in the water because it displaces some weight of water. Even an engine under water will displace something. for level flotation the placement of the foam is also important. For example you need more foam aft then forward because of the engine and battery, etc. You need foam higher up then just under the deck on port and stbd so the boat won't flip over. There are calculations from the coast guard you can use and most manufacturers start there. Then they actually sink the first boat and move weights around to simulate passengers and gear for level flotation when submerged. When restoring a boat the methods you use are up to you, you don't have to conform to any flotation req's from the coast guard. Just a very good idea for the safety of you, your family and others you may take boating. Boats under 20' and I/O's don't have those requirements. I think that's because it would take a boat full of foam to float a big V8 in a small boat and no room left to put people on it.

 

[Woodonglass]

Re: Floatation Foam

I seriously doubt the foam in your boat is structural. I also would advise you to put foam in her for floatation purposes. The Pink of Blue slab stuff from Lowe's or HD wold be more than acceptable to use and prolly a little cheaper and easier to install. Totally your decision. If you do decide to use the Pour in foam. the 2lb stuff would be my recommendation. You'll need approx. 2-16 lb kits that will run you approx. $160 bucks delivered.