replacing floor in ski boat, what to do about the foam

tfret

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So I started pulling up the floor in our 19' 1984 open bow ski boat this weekend. Wow, it was in worse shape than I thought. Luckily the stringers appear solid. The foam appears to be in good condition, however it seems that the bottom 1/4" or less of foam is soaked with water. My question: should I go to the trouble and expense to replace all that foam, or just leave it as is? What harm will a little water at the bottom be? Thanks for any / all advice.
 

Cadwelder

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Re: replacing floor in ski boat, what to do about the foam

Remove it, as it will only cause more problems in the future. The foam will never dry out. Just doesn't make sense to be removing the deck and not correcting all the problems underneath it.

Also be sure to core sample your stringers to make sure they are sound. Apperance can be misleading....many times.

CW
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

Thanks CW. I was leaning that way anyway. I do believe the foam provides some structural integrity and will use the pour in stuff. But I want to leave an open channel in the bottom for drainage. Does anyone have any tips on how to do this?
 

Cadwelder

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Re: replacing floor in ski boat, what to do about the foam

Just bore some limber holes along the way, and seal the inside edges of the holes good. You'll be fine that way.
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

When I pour in the new foam, what keeps it from sealing up the drain holes? I'm hoping to find a way to leave an air gap at the bottom of the foam to facilitate drainage under the foam.
 

Cadwelder

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Re: replacing floor in ski boat, what to do about the foam

I've seen pieces of PVC cut inhalf and laid in the bottom of each compartment....drill a bunch of holes in it.....
 

oops!

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tfret

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Re: replacing floor in ski boat, what to do about the foam

WOW, that's a wealth of information. There's some terminology I don't quite know, but I get the idea with both threads. I really like the ventilation idea and would like to try that. It seems that this moisture under the deck is inevitable, and it eventually causes rot. I know this question has probably been asked before so forgive my ignorance, but is there a problem with using the spray foam that comes in a can like "Great Stuff"?
 

oops!

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Re: replacing floor in ski boat, what to do about the foam

yes there is .....dont use it......

2 part pour in foam
 

oops!

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Re: replacing floor in ski boat, what to do about the foam

as far as the terminoligy that you dont know. please excuse my industry jargon.

please just ask here what you are unsure of.
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

I'm not sure what csm, tabbing, and peanut butter are, but I get the basic concepts of the threads. BTW - what's wrong with the foam in a can stuff, sure seems easier if the end result is the same. Just wondering.
 

Friscoboater

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Re: replacing floor in ski boat, what to do about the foam

It is different. I believe the great stuff is not closed cell, and the two part is. Plus you will spend more money using the canned stuff VS the 2 part. I put the foam back in my Sea Ray just for the security and sound deadening. Take a look at my Sea Ray build thread linked in my signature and you will find out all about Peanut butter, CSM and 1708. There are some videos too. Oops's thread also has a good recipe for PB.
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

Very helpful, thanks. Now I know what "tabbing" is. Frisco, I see you did your floor with the "cap" of the boat in place. I can see under the bulk head where it looks like you cut away the bottom of the seating in the open bow area. Is that right? I may do the same thing in mine to gain access to that floor. But how did you put the seating structure back together?
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

Unfortunately I have to store my boat outdoors all year. Despite the best covers and tarps etc, water does inevitably get into it. For that reason I really like the idea of installing drainage channels and deck venting to help keep all the hard work dry for many years. I'm all ears for any suggestions in that department too. Thanks again.
 

Friscoboater

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Re: replacing floor in ski boat, what to do about the foam

My cap would have been next to impossible to take off. It was glued in place, and is very, very heavy. My Sea ray is made with alot a fiberglass, and in some places is close to 5/8 of an inch thick, so when I cut out all the wood it did not sag at all. It was the only option for me, but it was really hard to work around.
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

removing the cap really isn't an option for me either due to location and space constraints. How did you put the open bow seating section back together? Fiberglass and epoxy?
 

Friscoboater

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Re: replacing floor in ski boat, what to do about the foam

Yep. It was not very easy, but I put it in one piece at a time.
 

tfret

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Re: replacing floor in ski boat, what to do about the foam

FYI - I spent some time on the phone with Dow yesterday, the makers of Great Stuff spray foam. The foam is closed cell and is actually coast gaurd approved for use as floatation in boats. That's the good news. The bad news is, it should only be used for filling small voids and sealing cracks. If you try to fill a large area with it, it will expand rapidly and the outer surface will cure first, sealing off air to the inner foam, resulting in a soft center that will never harden. You can still use it if you lay down lots of small lines of it. And do this in stages, allowing it to cure between stages. But this is time consuming and the cost per cubic foot is much higher than the pour in stuff. So in conclusion, I think it is fine for small foam repair and and sealing cracks, but it's really not going to perform well for a large area fill like between stringers.
 

Cadwelder

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Re: replacing floor in ski boat, what to do about the foam

oops said:
pvc alone does nothing because the pvc is a closed channel. so the water cannot get in to the drainage area.


Hey oops....don't think you read all I posted...I did say you have to drill a bunch of holes in it for the drainage to work...
 
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