Foam or Not !

sschefer · Jan 27, 2011

Re: Foam or Not !

Foam for floatation is only required for recreational boats under 20'. So the question as to if you can add foam is yes. Will it add to the boats ability to survive flooding? Probably not since the hull weight would likely exceed the displacement capability of the amount of foam you could actually get in the boat and still have room for the other amenities.

That said, using a spray in foam for sound deading and/or insulation from hot/cold situations is very common. If thats what you want most then go for it.

As for foam before or after glass, I think I would tend to go with the rest of the gang and glass first. If that prevents you from adding floation foam then I wouldn't add it since it most likely won't do you any good anyway.

kilowatts · Jan 27, 2011

Re: Foam or Not !

Hi Guys:

I also voted No. Here's why:

I'm not a big believer in the "foam for minimal flotation" theory. An earlier thread gave a string of calculations for the amount of foam required to keep a boat of a certain size and weight from sinking. After reading it I formed the opinion that the average trailer pleasure boat can't hold enough foam to keep it from sinking if you take into consideration the gas, people, and engines on board. I believe I have a boat with an excellent hull but it has around 950lbs of engine and outdrive hanging on the back along with 75 gals of gasoline and 2 or 3 heavyweight people on board. Add that to the hull weight and I think I'd need a house full of foam to keep that from sinking. Consequently when I replaced the subdeck I removed a few gobs of factory installed saturated foam, replaced the deck and sealed it up with no foam in there. If I do indeed founder and sink, I'll let you know I was wrong!

kilowatts

proshadetree · Jan 27, 2011

Re: Foam or Not !

Watch youtube. the have several sinking boats on there. Many go sort of down and turn over. The float even with wetish foam. I will say I for one would hate to go out 25 miles in the ocean with no foam. If you just small lake it then drop that junk. My Bayliner drums in rough water IE you can hear the pounding more than in a stock one. I will live with that just to run from foam and maybe rot.

Friscoboater · Jan 28, 2011

Re: Foam or Not !

According to searay, the foam in my boat is structural and sound deadening.

1fishbone · Jan 28, 2011

Re: Foam or Not !

I voted NO...but seems it's structural to THAT manufactures design.
I never owned a boat that needed foam for 'structural integrity' ...and never will!

sschefer · Jan 28, 2011

Re: Foam or Not !

USCG say's all pleasure boats under 20' have to be capable of level float. Manufacturers sacrafice boats to have this test performed. If you've taken the foam out and your boat sinks your insurance company probably won't pay for the recovery after they recover it, (yes EPA say's you have to recover it). Do I need to mention a trapped passenger drowning?

If the foam is structural then it needs to go back in.. That's pretty much a no brainer. I probably wouldn't bother with a boat that had structural foam from a restoration perspective but I'm sure they're fine as new.

Casull · Jan 28, 2011

Re: Foam or Not !

along with 75 gals of gasoline

Gasoline is lighter than water and won't make a boat sink.

Yacht Dr. · Jan 28, 2011

Re: Foam or Not !

Casull said:
Gasoline is lighter than water and won't make a boat sink.

Really... gas/petrol is lighter then H2O ??

Anything will help a boat sink..including tanks of fuel...

YD.

Cadwelder · Jan 28, 2011

Re: Foam or Not !

Yacht Dr. said:
Really... gas/petrol is lighter then H2O ??

Anything will help a boat sink..including tanks of fuel...

YD.

That part is true...gasoline is like 6.3 pounds per gallon and water is 8 lbs, but I think weight is weight as far as sinking goes.

stuartboater · Jan 28, 2011

Re: Foam or Not !

I am no expert for sure but adding foam does seems incorrect.
Wellcraft did not add foam when made. I dont remember seeing any having it of in the true older ones... before the move from Florida
Wellcraft boats are already heavy. Not sure how much weight foam adds. How will it affect your draft?
I would think it is impossible to keep moisture out of the foam, and there will be pockets of air, no matter what. Air pockets will eventually have condensation .... Condensation will cause blisters...
I dont know. I wouldnt do it.

proshadetree · Jan 29, 2011

Re: Foam or Not !

My Bayliner was supposed to have foam for structure, according to someone on this board. It might have. I did not put the foam back in. I did build a 3/4 inch floor in place of the original. I then glassed angels from the front to the back as sort of wells to be filled if punctured. I jetted them in a fashion with 1/2 pipe at lowermost section. Then mixed resin and csm with acetone to slow the kick to put the floor back in. Screwed down and watched some of the mix push out on the back. She may not keep all water out in the event of a rupture, but our lake banks are always close. Thats why and how I did not use foam in a boat that said it must have it. I only have 65 hours on her after this process. No cracks and she has been treated rough.

Yacht Dr. · Jan 29, 2011

Re: Foam or Not !

Cadwelder said:
That part is true...gasoline is like 6.3 pounds per gallon and water is 8 lbs, but I think weight is weight as far as sinking goes.

Nope..Im right..water is lighter then petrol..

Or are you talking about Specific gravity..water is more dense then gasoline..but molecularly h2o's atomic weight is less then gas

.

Take a pound of water and a pound of gas..which weighs more ? ..

Can I vote twice

.. no foam ...

YD.

SawDust{RM} · Jan 29, 2011

Re: Foam or Not !

Water Weighs 8.34 lbs per gallon

Something I learned in the 70's

Lou C · Jan 29, 2011

Re: Foam or Not !

When I re-did the deck in my 88 FW I e-mailed FW and they told me the foam was both for floatation and structural reasons and this made sense to me as there were 4 stringers and only 2 transverse bulkheads. I replaced the foam and sealed the deck where it met the stringers and hull sides with 3M 4200. All screw holes were sealed with 4200. If this boat rots again its a non issue to me because I am going to buy a nearly new boat next time with composite construction. I could feel the difference in solidity after standing on the deck with no foam for trial fitting of the wood vs the finished product. The boat is very solid out on the water. If you want to foam but are worried about it trapping moisture, why not coat the finished stringers in epoxy before foaming. Epoxy is pretty close to waterproof and will bond fine to poly if you used poly in your rebuild. If you used epoxy to glass in your stringers then I don't think there will be as much of a chance of a repeated rot issue as long as all deck penetrations are well sealed. I for sure want something to keep some part of the boat above water if the worst ever happens.....

Yacht Dr. · Jan 29, 2011

Re: Foam or Not !

Yes it does..

Take your gallon bucket and fill it with water..8.34 lbs

Empty it and now fill that same gallon with gasoline.. it weighs approx 6.25 lbs.

Empty it again..and fill it with packing peanuts,gold,cockeroaches or even hairballs from your cat..they will All have different weights.

Your talking specific gravity of volume..not Atomic weight..

H2o is lighter then fuel .. not by volume because water is more dense..

Thats my story and im stickin to it

. cough..any chemist want to jump in here to my defence would be nice

YD.

Cadwelder · Jan 29, 2011

Re: Foam or Not !

Yacht Dr. said:
Yes it does..

Take your gallon bucket and fill it with water..8.34 lbs

Empty it and now fill that same gallon with gasoline.. it weighs approx 6.25 lbs.

Empty it again..and fill it with packing peanuts,gold,cockeroaches or even hairballs from your cat..they will All have different weights.

Your talking specific gravity of volume..not Atomic weight..

H2o is lighter then fuel .. not by volume because water is more dense..

Thats my story and im stickin to it . cough..any chemist want to jump in here to my defence would be nice

YD.

Ok, ok, ok, I don't think we were getting that specific, just that per gallon the gasoline weighs less, you said it yourself. I'm not a chemist, by any means just a guy that learned this weight back in high school. Healthy to argue a little from time to time.

SawDust{RM} · Jan 29, 2011

Re: Foam or Not !

uhh.. I'm A Chemist, but thats not important right now.

Specific Gravity of Distilled water is 0.000 your 1st morning pee should be between 1.020 & 1.030 after you have been drinking Beer all day it probally be less than 1.010
The Gold analysis of Specific Gravity uses a Hydrometer its a floatation device
Atomic weight / Osmolarity / Specific Gravity
all different analytes

Cadwelder · Jan 29, 2011

Re: Foam or Not !

SawDust{RM} said:
uhh.. I'm A Chemist, but thats not important right now.

Specific Gravity of Distilled water is 0.000 your 1st morning pee should be between 1.020 & 1.030 after you have been drinking Beer all day it probally be less than 1.010
The Gold analysis of Specific Gravity uses a Hydrometer its a floatation device
Atomic weight / Osmolarity / Specific Gravity
all different analytes

Cool a chemist.....so which is heavier....water or gasoline?

Bondo · Jan 29, 2011

Re: Foam or Not !

Take your gallon bucket and fill it with water..8.34 lbs

Ayuh,... Is that Freshwater, or Saltwater.....

You can take a Steel Tank, 'n fill it with Freshwater,...
And,...
It'll float in Saltwater....

Yacht Dr. · Jan 29, 2011

Re: Foam or Not !

Well Im an ol' salty dog..

.

YD.

Ps. I just pee'd on my refractometer and you dont want to know the results hehehe

.

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