Styrofoam?

[bigmcgiv]

Re: Styrofoam?

heated discussion, i was thinking packaging peanuts?

 

[chconger]

Re: Styrofoam?

No heat intended. Just want to ensure its clear the government (USCG) advocates urethane pour in and the underlying logic behind it.

Polystyrene is not recommended by the government for any craft that has fuel on board.

And it's all good.

 

[jbcurt00]

Re: Styrofoam?

Packing peanuts?

NOPE!

Nothing good comes from that:

My 1st Jet had 3 of the big NO's: Bedliner, packing peanut flotation & pressure treated lumber (on top of the bedliner, not against bare aluminum & also sprayed w/ bedliner)

Before anyone brings it up, the Mythbuster float your boat w/ ping pong balls isn't a good choice either :facepalm:

 

[bigmcgiv]

Re: Styrofoam?

well darn, you bust my bubble. i planning to take mine to get sprayed.

 

[Ike-110722]

Re: Styrofoam?

nor do they want to think about the fact that the 2 part expanding urethane foam is the only one that is USCG approved,

This is not true. I spent over twenty year with the USCG enforcing regulations for flotation in recreational boats. There is no such thing as USCG APPROVED foam (the sole exception is fire resistance for insulation foam used on commercial vessels) This is a myth perpetuated by the foam industry. You can use any foam you want. The USCG regulation only requires that any foam used where it would be exposed to petroleum products , gas, oil,etc,. and caustic cleaners, be resistant to those things. If the USCG had approved foam the division I worked in would have been the one doing and we don't approve foam. The industry uses pour foam (two part spray foam) because it is easily applied and bought in volume, cheap.

In fact you aren't even required to use foam. The flotation requirement is a performance standard, the boat has to meet either level or basic flotation depending on thee type of boat. You can achieve this any way you want. I have seen all sorts, plastic bottles of various type, beer and soda cans, ping pong balls, air chambers and other things. As long as it displaces water and meets the performance standard it is ok.

I have built three boats using the pink styrofoam from Home Depot. I either encase it in fiberglass and epoxy resin, (polyester resin will dissolve styrofoam) or I bag it in vinyl plastic. Vinyl is resistant to just about everything.

See what I did on my 1972 Sea Ray 190. New Boatbuilders Home Page - Projects - 1972 Sea Ray 190 Rebirth

 

[jbcurt00]

Re: Styrofoam?

well darn, you bust my bubble. i planning to take mine to get sprayed.

You could if you wish, but it's heavy & not designed for a marine environment, IMHO, partially based on the unpleasant experience attempting to remove it from my boat.

 

[Woodonglass]

Re: Styrofoam?

Thank You ^^^ I'm glad to finally get someone In the KNOW to give the forum the scoop on the USCG and this FOAM issue. It's kinda like the old saying..."Whatever Floats yer Boat!!!!" Pour in Foam's biggest asset IMHO is that it adheres to the hull and provides additional structural support.

That's the Old Dumb Okie's take on this!!!!

 

[Ike-110722]

Re: Styrofoam?

Pour in Foam's biggest asset IMHO is that it adheres to the hull and provides additional structural support.

Yes it does. Now you know Boston Whaler's secret to the structural rigidity of their boats (they used much denser foam). But that is also one of the reasons it is so hard to get out when it becomes water logged. Another thing, not all foam becomes waterlogged. There are 20 and 30 year old boats with perfectly good foam in them. It is all in the application. I could go on at length about this. I was involved in some studies about the problem. But stick, or block foam, pre-manufactured foam, does not do this. Put in block foam, bag it or encase it to keep away oils, gas etc, and 1000 years from now archeologists will be digging it out of the landfill in the same condition it was when it was made.

 

[jigngrub]

Re: Styrofoam?

This is not true. I spent over twenty year with the USCG enforcing regulations for flotation in recreational boats. There is no such thing as USCG APPROVED foam

Approved was a bad word choice on my part, I should have used compliant.

... and I was wrong about it being the only compliant foam, polystyrene foam is also compliant.

I learned this by doing some research... if you have questions and search long enough on interweb you will more than likely find an answer.

I found some good answers here:

Flotation - Flotation Materials

I found this part especially interesting:

b) Plastic Foam Blocks and Other Shapes


1) A method of identifying foam blocks and other shapes must be employed to assure that each boat gets the correct amount of flotation in the correct location.

2) Expanded polystyrene foam must not come in contact with uncured polyester resin or fumes.

3) Foam blocks and other shapes must be secured so that no movement in any direction occurs that will effect the flotation's performance.

4) Installation must be in a manner that will prevent:
?damage from occupant contact
?deterioration from exposure to direct sunlight
?damage from normal use of the boat.

5) The space provided for the installation of foam blocks must be large enough to prevent the necessity of using force that will deform the shape of the block during the installation process. Deformation will lower the volume, and therefore the total buoyancy, of the foam block.

... and especially #3:

3) Foam blocks and other shapes must be secured so that no movement in any direction occurs that will effect the flotation's performance.

I would consider the upward pressure/movement unsecured foam blocks can and will produce on a boats decking as the boat takes on water to be non-compliant. Foam blocks should be secured to the hull and and shouldn't rely on the decking to hold them in place. I don't know how anyone could achieve this with their foam wrapped in plastic bags.

I also found this part interesting:

. In densities of less than 2 pounds per cubic foot, it may absorb significant amounts of water.

Here:

stated requirements.

Of the many foams available, foamed polystyrene and polyurethane are the most common. They are noted here because of their broad use, but not to the exclusion of other types of flotation material.

Foamed polystyrene is a low-cost material produced from expandable beads ("pop corn") or extruded in the form of billets or boards. The common name is "Styrofoam." In its common forms, it is readily dissolved in gasoline and is highly flammable. There are special compounds of polystyrene foam that are solvent-resistant and self-extinguishing. One objection to foamed polystyrene is that it cannot be foamed in place, and it usually cannot be produced in a boat builder's plant. Caution is necessary because some varieties have "wormholes" which reduce the flotation value.

Polyurethane foam is another widely used buoyancy material. It is usually foamed in place or molded into specific shapes before installation. It is also available in slabs and billets. Polyurethane foam is normally highly resistant to gasoline and oil, particularly in densities of 4.0 pounds per cubic foot and higher. Even in densities of 1.5 to 2 pounds per cubic foot, it is considered very resistant to gasoline and oil. Polyurethane foam is flammable, but it can be made self-extinguishing. In densities of less than 2 pounds per cubic foot, it may absorb significant amounts of water.

Air chambers used to achieve flotation are usually made of plastic materials. They must be capable of withstanding the same solvent-resistance tests as other flotation materials, and they must pass the required 18-hour submergence preconditioning before undergoing the flotation tests.

I understand this to mean that the more dense (heavier # rating) the urethane foam is, the more water resistant it is. So if you're worried about your urethane foam absorbing water you may want to step up to the 3 or 4 lb. foam... but 2 lb. is acceptable and compliant.

Other parts of this article (pages) I found interesting were calculating the amount of foam needed and foam placement for level floatation... something a lot of people don't take into consideration when designing their floatation system.

 

[Ike-110722]

Re: Styrofoam?

Yeah that's all pretty good stuff (blowing my own horn since I had a small hand in writing it.) LOL!

Don't apologize for saying Approved. We were constantly sending Cease and Desist letters to foam manufacturers for saying Approved in their advertising. Their marketing people simply don't talk to their technical people. And Foam Manufacturers aren't the only ones. Surprisingly there are only a few things on recreational boats that need to be Coast Guard Approved. You can count them with your fingers.

Almost all builders use 2 lb density foam. That means one cubic foot weighs two lbs, so one cubic foot gives you 60.4 lbs of flotation in fresh water. All the calculations in the USCG Handbook and ABYC standards are based on 2 lb density foam. It is very suitable for flotation foam. I you use those formulas you have to adjust them for four lb or six or whatever you use.

Yes denser foam is less prone to water absorption since it has much smaller cells and the cell walls are thicker. But if you use 4 lb foam you have to remember you are adding double the weight to the boat, 6 pound, three times the weight, and lessening the amount of weight it will support, meaning it takes more foam, to support the boat, engine, gear and passenger weight. The bigger the boat the greater the weight impact. It increases by the square just like volume does. This also has to be subtracted from the maximum weight capacity as hull weight. So really you are better off using 2 lb.

Actually the ideal is air because a cubic foot of air supports 62 lbs in fresh water, but on boats over 2hp the boat has to meet the standard with the two largest air chambers punctured, so if you use air chambers make a lot of them. They can't be integral with the hull, the exception is boats less than 2hp and manually propelled. All chambers count and they can be integral with the hull.

Placement of foam is crucial for level floation. We tested boats for flotation on a routine basis and of those that failed it was almost always not enough foam where it was need most. In other words they heeled too much, or even rolled over. In level flotation the point is to get the boat float, with passengers, engine and gear, in a relatively level attitude. If it heels more than 30 degrees it fails. Usually the engine was the culprit. There simply wasn't enough foam at the starboard quarters to support and stabilize the outboard. If you put all the foam in the bottom the boat rolls over and floats level upside down. Not good. I you put too much up under the gunwales the water level in the boat may never get high enough to contact the foam and the boat will capsize. And so on. It has to be placed where it will work and do the most good.

In basic flotation (inboards and I/O's) this is not an issue the boat simply has to float with some part of the boat out of the water.

 

[Landof9000lakes]

Re: Styrofoam?

Some did use sheet foam,I can't. It is part of the rigitity of the hull. Those that use sheet foam where it should not be are compromising the hull.
Grub

I agree.


However I do also believe that the way of installing the board based foam that some are starting to use IS adding structural support much in the way that pour-in foam is.


I'm referring to the foam board install method that packs the foam vertically and tightly.

 

[jigngrub]

Re: Styrofoam?

Yes denser foam is less prone to water absorption since it has much smaller cells and the cell walls are thicker. But if you use 4 lb foam you have to remember you are adding double the weight to the boat, 6 pound, three times the weight, and lessening the amount of weight it will support, meaning it takes more foam, to support the boat, engine, gear and passenger weight. The bigger the boat the greater the weight impact. It increases by the square just like volume does. This also has to be subtracted from the maximum weight capacity as hull weight. So really you are better off using 2 lb.




If you put all the foam in the bottom the boat rolls over and floats level upside down. Not good. I you put too much up under the gunwales the water level in the boat may never get high enough to contact the foam and the boat will capsize. And so on. It has to be placed where it will work and do the most good.

In basic flotation (inboards and I/O's) this is not an issue the boat simply has to float with some part of the boat out of the water.

I don't really consider the additional weight of a denser foam a factor compared to the benefit of being more water resistant. We're only talking 20 more lbs. for 3 lb. foam and 40 more lbs. for 4 lb. per 20 cubic feet of foam and most boats don't even use 20 cubic feet of foam... I've got tackle boxes that weigh more than 40 lbs.!


The roll over/capsizing can be minimized by leaving out some foam along the keel for water to accumulate and ballast the boat as described here from the same article I quoted earlier:

shall not be included as part of the flotation required.

Flotation material located at the sides, as far aft and as high as possible, will help make boats with machinery located aft float level when swamped. Some boats may require the keel area inside the boat to be void of flotation material so that the space can flood from either end to provide proper balance in the swamped condition

My boat has this design and is very stable when I launch without the drain plug in and then fish all day because I don't even notice it.

Keel area void of foam:


Floatation below the gunwales:


... and my boat floats better than this because my motor is only a 50 hp and water doesn't even come up through the deck drain:
Lund Boat Floatation Video - YouTube

I bought my boat new back in '98 and the 15 yr. old urethane foam is still bone dry. The boat has always been kept outside, but covered with the drain plug out.