Hull Foam....why>?

[bigheaded5]

I want to know WHY manufactures seem to fill the boat with foam under the floor. I cant imagine that small amount of foam being able to keep the boat from sinking or even add any flotation to it at all. From what I have seen in the boats I have worked on, all the foam did was trap water and help rot the floor.

So does any one know WHY they put foam under the floor, and do they still do that to new boats?

Ed

 

[tazrig]

Re: Hull Foam....why>?

1) It's the law to have certain amount of flotation in each boat
2) Sound proofing
3) Structural integrity in some

 

[bigheaded5]

Re: Hull Foam....why>?

I figured sound proofing might be a reason.....the LAW, ok? Structural, I'm not an engineer so i cant comprehend that one.

Thanks for your input.

Ed

 

[tazrig]

Re: Hull Foam....why>?

some boats are so cheaply made today that the foam plays a part in holding them together. In some high end boats such as some Boston Whaler's the foam "is" the core structure, sandwiched between 2 shells of fiberglass.

 

[bigheaded5]

Re: Hull Foam....why>?

I can comprehend foam as flotation IF there is enough foam to displace enough water to keep the mass floating.... But in my case, a few cubic feet of foam under the floor to keep a 2200 pound boat and motor from hitting the bottom? I dont think it would even make it ANY lighter after its soaked with water. Dont tell the boat police, but Im leaving the float OUT on my restore in place of air to circulate and preserve the floor.

 

[tazrig]

Re: Hull Foam....why>?

Watch out for the boat cops. :mod::mod::mod: LOL

 

[jigngrub]

Re: Hull Foam....why>?

, but Im leaving the float OUT on my restore in place of air to circulate and preserve the floor.

See you at the bottom!

 

[bigheaded5]

Re: Hull Foam....why>?

see me at the bottom...oh stop lol

Ed

 

[kfa4303]

Re: Hull Foam....why>?

The foam will only become water logged if you use the wrong kind. So long as it is closed cell (not white styrofoam) it will be fine. You can even use the pink/blue insulation foam board from Lowes/HD in a pinch. As the others have stated, modern vessels are required to have a certain minimum amount of flotation such that 1"-2" of the boat will remain above the water line even if it becomes completely submerged (aka "swamped"). There are also several forms of structural foam that are used alone, or in conjunction with various epoxy and vinyl ester resins to add integrity to the hull. While antique vessels are often exempt, many of us (myself included) find ways to add extra foam/flotation for good measure.

 

[bigheaded5]

Re: Hull Foam....why>?

I hear you and understand the different types of foam my manetee had 2 part foam in it and it was pretty much useless from being installed at the favtory in 1986 besides, I dont plan to sink

 

[lokonn]

Re: Hull Foam....why>?

It is your boat, you can do what you want. Nobody plans on sinking or swamping their boat. Nobody plans on falling overboard either. Both happen. If it is only you, your choice. If others are relying on there being some form of secondary flotation to save their butt, you made the decision for them, and you'll have to live with that. Good luck with whatever you decide to do.

 

[GA_Boater]

Re: Hull Foam....why>?

Who does?

After the boat leaves the dealer, an owner can do anything they want. The foam installation is only required by the manufacturer. After you get swamped, come back and tell us if leaving the foam out was a good idea. If you can.

 

[bigheaded5]

Re: Hull Foam....why>?

Im sorry....that comment "I dont plan to sink" was meant as a joke..... Trust me im NOT that guy who assumes everything will work out for the best and enters into something blindly. I will consider foaming the boat..... but I am leaning toward not.

 

[tpenfield]

Re: Hull Foam....why>?

Boats 20 feet and less are required to have positive flotation. NMMA standards are for boats up to 26 feet to have positive flotation. The foam in boats provided that.

The foam also strengthens the hull and allows it to absorb and withstand greater impacts, adds rigidity, etc.

Foam gets blamed for structural rot, because it ends up holding the evidence. However, there are other factors at play in most cases.

On a restore, it is your choice. But you should take into consideration why the foam was there originally and what the adverse effects would be of not replacing it.

 

[jigngrub]

Re: Hull Foam....why>?

I want to know WHY manufactures seem to fill the boat with foam under the floor.Ed

I think this is a pretty good reason:

Lund Boat Floatation Video - YouTube

I find it hard to believe at the number of people on this site that can't comprehend the function of floatation foam in a boat.

I also find it pretty unbelievable at the number of people that don't understand the care and maintenance a boat should be given to keep it from becoming saturated and rotten. NEWS FLASH!!!: Your boat is made of wood and foam and isn't designed to be constantly exposed to the outside elements!

Wet foam and rotten wood only happen when bad boat owners do bad things to good boats. Keep your boat covered with the drain plug out (if on a trailer) or with an automatic bilge pump if kept on the water and your wet foam and rotten wood problems will be nil.

People that don't understand the expanding urethane foam also amaze me, this is the best stuff you can get! It bonds itself to the hull and will actually act as an interior sealer should you breach your hull, it'll keep water from entering your boat and you'll be able to make it back to the launch safely.

Sink or float, the choice is yours.

 

[bigheaded5]

Re: Hull Foam....why>?

I do appreciate all the advice and information but why does it all have to be made to sound so ominous lol but I do appreciate you all answering my question as to WHYboats have foam in them

Ed

 

[jigngrub]

Re: Hull Foam....why>?

I've never been on one, but I'm sure you get a very ominous feeling when you're aboard a sinking boat or ship and realize that you can't reverse the situation.

 

[Stampede]

Re: Hull Foam....why>?

I'm at that point right now.Ready to replace the floor foam and am wondering the difference between the sheet stuff or the expanding stuff.Does the expanding stuff come in cans that you spray in after the floor in down?

 

[Georgesalmon]

Re: Hull Foam....why>?

You will get two part foam in cans that mix 1:1 and pour in and expand. The reason manufacturers don't use sheet foam much is because it will not pass Coast guard requirements for flotation foam. Partly because it will soften or melt in the presence of gasoline. Outboards under 20 foot must meet both basic and level floatation requirements. As for how little foam you think is in your boat remember that everything in the boat when submerged displaces water, for ex: a 50 pound battery might weigh only 25 pounds under water because it would displace 25 pounds of water.

 

[Grandad]

Re: Hull Foam....why>?

I can comprehend foam as flotation IF there is enough foam to displace enough water to keep the mass floating.... But in my case, a few cubic feet of foam under the floor to keep a 2200 pound boat and motor from hitting the bottom?

Use the right kind of foam and it won't get saturated. You don't need a lot of math if you also use some logic. If a PFD floats a 220lb man, then adding flotation equivalent to 10 PFD's will float your 2200 lb boat. - Grandad