no foam?

[trickster734]

Hey all, just started ripping out the floors in my unit, '72 Cobia Tornado, floors are not orginal, and have been replaced but obviously need it again, stringers look like mulch, anyway, there is no foam at all under the floor, is this bad, should i include in new floor build? Seems right answer would be to include but i am just polling the audience. thanks.

 

[JasonJ]

Re: no foam?

I would foam it, it makes the boat safer and stronger, plus it can dampen noise.

 

[Chris1956]

Re: no foam?

Trickster, The foam on my boat not only fulfills the requirement to float if full of water, but adds much strength and ridigness in between the stringers and frames. I think you should definately foam it. I would use pressure treated solid lumber( make sure it is dry) for the frames and stringers and glass them in. Use folded, saturated cloth between the hull and the stringers to help them adhere. If you use glass cloth and resin on top of the foam to grab the underside of the floor, it will make the foam more waterproof and make the boat a bit stronger. Also try to screw (use stainless) the new floor into the new stringers and frames.

 

[brad20653]

Re: no foam?

So with foam under the floor the boat wont sink? What kind of foam where do you get it? Sorry not trying to hijack your thread.

 

[JasonJ]

Re: no foam?

Brad, as long as the amount of foam in the boat displaces enough water, the boat won't sink. 2 part foam is the best way to go, although other materials have been tried or at least considered. A place like USComposites.com has the foam, as well as other sites. This all depends on the size of the boat and the amount of room available for foam.

 

[AK_Chappy]

Re: no foam?

Originally posted by JasonJ:<br /> Brad, as long as the amount of foam in the boat displaces enough water, the boat won't sink.

OK,<br />JasonJ, you piqued my interest on this one. I have a boat I am preparing to re-do and would like to know.......<br />How do you know how much foam is enough foam? I really don't want to put the boat in the water and fill it up to test it? j/k I would NEVER attempt this.<br />Is there a formula for this?<br /><br />AKChappy

 

[Terry H]

Re: no foam?

AKFishingNut <br />the USCG has a formula for this...I can't tell you where to find it, but if you find them on the web you can likely navigate to where you want. I know this because I've beem there...maybe someone will come on with the correct address for what you want...just a Thought

 

[E. E.]

Re: no foam?

The link below is one I found here on iboats (I think) to the USCG Safety Standards for Backyard Boat Builders. The filling the boat with water idea is in there as well as other things. Hope this helps.<br /><br /><br /> http://www.uscg.mil/d8/mso/louisville/WebStuff/comdtpubp16761_3b.pdf

 

[JasonJ]

Re: no foam?

A boat, even fully submerged, is displacing water by virtue of its structure. It may weigh 1000 lbs on dry land, but only weigh 700 lbs or less under water because of the water that is physically displaced. You only need enough foam to make up that difference plus occupants and gear. Since it would be very difficult to calculate how much water a boat displaces, you can simply put as much foam in as you can. Generally, 16 cubic feet of foam is enough for a 17 foot boat, so you could go from there. Another way is to try to put enough foam in to displace enough water to come close to the boats dry weight (water is 65ish lbs per cubic foot).

 

[snapperbait]

Re: no foam?

When in doubt, FOAM IT!...

 

[AK_Chappy]

Re: no foam?

That's why I love this site. You can learn so much so quickly. Thanks for the link, that was some pretty amazing stuff in there.<br /><br />AKChappy