Non-soakable foam ?

[BobfromSWOhio]

I just purchased a 1982 Renken 900 STD project boat w/no motor or outdrive. It is 18' 8" w/a closed bow. The rear part (and maybe their entire length; I have not removed all of the floor) of the stringers are rotted. I will have many questions as I move forward but the first deals w/the blown in foam under the floor. The existing foam seems completely dry (last in water 2 months ago) so is it the type to not soak up water? Also, is it necessary to replace the foam to assure sturdiness of the hull? What type, name brand, of foam should be used? Are the blue sheets of contractor's foam insulation OK to use. All recommendations appreciated.

Thanks.

 

[robert graham]

Re: Non-soakable foam ?

I've heard of folks packing their under-floor areas with the Swim-Noodles, closed cell foam toys kids use in the swimming pool. They're cheap, easy to cut, water would drain through and around them, and they don't absorb water. Seems like a "creative" idea, but still pretty darn good! Just an idea!

 

[109jb]

Re: Non-soakable foam ?

When I did my sea ray I initially thought the foam was dry too. The top 1/2 inch or so was. I tried a real sciientific experiment. I took a screwdriver and plunged it into the foam and worked it around. Water was there big time. As far as non-soakable foam, the foam used is closed cell and is supposed to be waterproof. The 2 lb density stuff has proven it isn't totally waterproof. My theory is that for the lower density the foam has to expand more and when it does the cell walls are thinner and eventually water can get in. For this reason, when I replaced my foam I used the 4 lb density foam. It added about 20 pounds in weight, and has about a little less bouancy, but I believe it will be much more resistant to water absorption.

 

[PiratePast40]

Re: Non-soakable foam ?

There are more than a few discussions about foam over on the restoration forum. There is also some decent information on manufacturers pages. US Composites, JGreer, and Tapplastics are a couple that come to mind.

The issue of weather or not foam flotation is a good idea seems to generate some controversy so be prepared to hear some different opinions.

 

[tmcalavy]

Re: Non-soakable foam ?

Get some PVC pipe and cut some teeth into one end, jam/push the toothed end down into the foam, twist and pull a core sample. The only way to check of the foam is really dry down to the hull. As noted, if you replace your foam...you can use closed-cell foam sheets or other products (noodles) from the big box stores. I used sheets of pink contractors foam from Home Depot...rated for use on the outside of concrete foundations. Trim it to fit and pack it in there...leave some space under the foam so water can drain to the stern/bilge.

 

[BobfromSWOhio]

Re: Non-soakable foam ?

Thanks for all the feedback. Swimming pool "noodles" and pink foundation foam seem like especially good ideas.

 

[geeco1]

Re: Non-soakable foam ?

One thing that I would suggest,....if you use the Pink foam from HD (blue works also) do not buy the thick 2 inch panels. They are too hard to work with. Buy the 1/2 inch panels. They are easier to cut and pack. I used the 2 inch panels but it was a real pain trying to get them to fit. There really isn't as much space under your deck as it seems.

 

[ezmobee]

Re: Non-soakable foam ?

My noodleage:

 

[Yacht Dr.]

Re: Non-soakable foam ?

Hello m8s..

I would like to throw my pro 2 cents in on the whole foam thingy..

Noodles Vs. Insulation pink/blue board Vs. 1 or 2 part foam.

Foam has NO affect on the bouyancy of any vessel ( in fact it is weight although minimal in small applications ).

Bouyancy Vs. Floatation .. or are we talking part of "structural" ?

1. Bouyancy .. Your boat Will Not Sink unless it takes on more Weight than its hull is capable of sustaining.. ( get a milk jug in your bath and see how much pressure it takes to drop it to the point where the opening starts to take water ). Thats bouyancy..

2. Floatation.. the amount of closed compartments that holds air ( including foam or not foamed ) that displaces water thus giving 8 lbs/ per gallon minus the weight of the "foam" if applied. Imagine a container full of empty soda cans compaired to one that has solid packed full soda and ice..one will float and one will sink..

Now on to the " Flotation " models..

1. Noodles = Simple pack anywere boat floatation devices.. No Structural qualities. If you somehow start to take on water then the "noodles" should have the volume to float the boat when "swamped". ( thats a lot of noodles ). And seeing as there is no bond with said Noodles on the hull..then you have a risk of just ripping the deck/floor off if not accounted for that in your construction..If its a hole in the bottom then there is nothing between the noodles to stop water coming in ( its not closed cell ) and will drown untill your noods stop your boat from completely sinking or barely floating.

2. Insulation boards.. basically same as the #1 .. noodles but in a different shape/comformability..

3. 1-2 part foam .. Same as the floatation above however water has a slower point of entry ( eventually your boat will swamp..but the amount of water/hr is drastically reduced ). It will not give you any more bouyancy but it could give you more time to get to more shallow water. It is more a pain to remove .. but not replace. It also has "structural" qualities .. absorbing minor hits from the shell of glass alone..

Best bet, IMHO, is to not Put a hole in your boat in the first place.. ( no foam ) .. and if you do have the missfortune when you cant make it back to land..then you should have better personal floatation or backup devices. If your thinking of putting whatever foam in your boat then you should do the math on the floatation factor of that foam..

YD.

 

[Greg Mrozinski]

Re: Non-soakable foam ?

Great response Yacht Dr.
I don't plan on getting a hole in my boat so I passed on foam. Personal floatation...absolutely.

 

[109jb]

Re: Non-soakable foam ?

Definition of Bouyancy: "The tendency or capacity to remain afloat in a liquid or rise in air or gas."

Hence, if the boat is swamped the foam provides the "bouyancy" to keep the boat off the bottom.

 

[tmcalavy]

Re: Non-soakable foam ?

Great pix of the swim noodles in action. Huzzah for swim noodles.

 

[Yacht Dr.]

Re: Non-soakable foam ?

Definition of Bouyancy: "The tendency or capacity to remain afloat in a liquid or rise in air or gas."

Hence, if the boat is swamped the foam provides the "bouyancy" to keep the boat off the bottom.

Keep it off the bottom of what ?

Like I said .. the "floatation" factor would keep you off the bottom..If you had enough foam for your drives and hull..( its not possible with foam filled ).

Your hull factor will keep our boats afoat .. unless it gets swamped/hole..not flotation foam..LOL..your boat is gonna sink m8..

Grab your personal gear and get out.. hope you have insurance if your boat sinks..because no Way in hek will your foam save your boat m8...

YD.

 

[109jb]

Re: Non-soakable foam ?

First et me say that my post was meant to be in jest. Apparantly it didn't come across that way.

Keep it off the bottom of what ?

The bottom of the lake, river, ocean or whatever body of water you happen to be on.

Like I said .. the "floatation" factor would keep you off the bottom..If you had enough foam for your drives and hull..( its not possible with foam filled ).

Your hull factor will keep our boats afoat .. unless it gets swamped/hole..not flotation foam..LOL..your boat is gonna sink m8..

I disagree with this. First of all 33 CFR 183 prescribes the tests that a manufacturer needs to do to show that a boat under 20' will stay on top of the water if swamped or with a hole in it. Specifically, 33 CFR183.220 g states

"(g) The boat must be swamped, allowing water to flow between the inside and outside of the boat, either over the sides, through a hull opening, or both. Entrapped air in the flooded portion of the boat must be eliminated."

Grab your personal gear and get out.. hope you have insurance if your boat sinks..because no Way in hek will your foam save your boat m8...

YD.

Oh yeah? Check this out
http://walleye.outdoorsfirst.com/watch.asp?id=2087

I'd say it has enough holes in it.

 

[Reel Kahuna]

Re: Non-soakable foam ?

Great response Yacht Dr.
I don't plan on getting a hole in my boat so I passed on foam. Personal floatation...absolutely.

So you didn't put foam in?

I'm about to replace my deck so I don't know if the foam is water logged or not.

 

[Revenge]

Re: Non-soakable foam ?

I have notice our pool foam noodles start to break down after a while. I would think twice about using them.

 

[Bob_VT]

Re: Non-soakable foam ?

I have notice our pool foam noodles start to break down after a while. I would think twice about using them.

The ones in your kids toy box? UV breaks down most foam products and being beneath the decking is safe from UV.

 

[Yacht Dr.]

Re: Non-soakable foam ?

Hello 109..

http://law.justia.com/us/cfr/title33/33-2.0.1.8.44.7.html

Your kinda taking things out of context..

Your Link to your vid does not show much other than alot of water draining out of those holes ( If you ask me there is Way too much water draining out of those nice 4" holes then what a typical Foam filled boat would dispurse ). It looks like a picture perfect Vid to me m8..

Im done ..

YD..

 

[Alpheus]

Re: Non-soakable foam ?

Your Link to your vid does not show much other than alot of water draining out of those holes ( If you ask me there is Way too much water draining out of those nice 4" holes then what a typical Foam filled boat would dispurse ). It looks like a picture perfect Vid to me m8..

Yep you're right, its fake. George Lucas made that clip. Its all C.G.I. in front of blue screen.

Oh and in case you're wondering. Yes there is a bit of sarcasm in my post...

 

[109jb]

Re: Non-soakable foam ?

Hello 109..

http://law.justia.com/us/cfr/title33/33-2.0.1.8.44.7.html

Your kinda taking things out of context..

Your Link to your vid does not show much other than alot of water draining out of those holes ( If you ask me there is Way too much water draining out of those nice 4" holes then what a typical Foam filled boat would dispurse ). It looks like a picture perfect Vid to me m8..

Im done ..

YD..

What am I taking out of context. The part where the regulations say manufactured boats under 20' have to float when swamped???

Also, are you really saying that the video doesn't show a boat full of holes still floating??? I guess they must be using smoke and mirrors.

I've actually showed evidence that it can work. I'm the one that's done.