Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

[sledrescue]

I am in the process of redoing my floor/decking in my 1976 Glastron Carlson CV-16. The old flotation foam was waterlogged. Floor had a couple of minor soft spots. Stringer is fine and solid. Transom is in good condition from inspection.

Question #1. Original flooring was 1/2" thick. I am trying to figure if I should stay with 1/2" or bump up to 3/4" plywood.

Question #2 Should a person install new flotation foam or not? If so, I have heard of some using the pour in expandable foam and others that buy the yellow closed cell foam from like Menards, Lowes, Home Depot and yet others say use a combination of the sheet foam cut down to size and then embed with pour in expandable foam. And then there are those that say don't reinstall any foam.

Question #3. Should a person use a hole saw and put 2 ventilation holes in the floor near the transom and cap them with PVC style unscrewable cap in 2 areas near the transom and 2 areas up by the console. This way a person could force air down into and underneath the floor/bilge area when the boat is in storage. I have blowers to exchange air and dry things out if and when they would get wet. The problem goes back to question # 2 to foam or not to foam. The holes that would be cut would then be worthless if expandable foam was used to core fill the bilge area. And core filling the bilge area right to the bottom of the floor/decking could also trap moisture long term. I want to do this repair right the first time. I like the ventilation idea with PVC screw in caps to be able to vent the area when the boat is not in use. I always store the boat indoors when not in use.


LIKES or DISLIKES?? Opinions or suggestions? Pro and Cons?

 

[tpenfield]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

If you thought that the original decing was not stiff enough, then you could go with 3/4".

Yes to foam, the boat is supposed to have it as per regulations.

A few access holes are always a good idea . . . it is a matter of where they would do the most good.

 

[tfret]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

1. Stick with 1/2" that will be fine.
2. Yes, use pour in foam. You'll be disappointed with it if you don't.
3. Lots of work probably little benefit. Search my recent thead of 1984 Dixie ski boat floor restoration and you'll see how I installed limber holes that allow drainage to the bilge of any water that might get in there.

 

[PiratePast40]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

I went with 3/4" throughout my boat when I did the rebuilding and wish I would have stuck with 1/2" and saved some weight. Especially since I used foam and that adds ridgidity to the deck.

Foam will allways be a debate but I did use the pour foam on mine. Some will tell you that the foam adds to the destruction of the wood and if you use it, you'll need to do the whole job over again 28 years from now. Don't know of any great savings by using sheets or pool noodles to suplement the poured stuff. Just seems like extra work. I've heard of people using PVC tubing for leaving channels along the hull for drainage so that any water has a path to the bilge. That might not be a bad idea and could give you some piece of mind.

As far as regulations for flotation foam, I believe that only applies to manufacturers.

 

[westexasrepublic]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

use pour foam, cut corners somewhere else. click the link in my sig. view my thread also.

 

[Cadwelder]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

Ditto on 1/2" its just fine, I use it for all decks

Foam is acutally required and I wouldn't do a boat without it, helps add some stiffness to the structure as well. (2lb foam is fine)

Don't know about the ventilation idea, never seen it done, but don't see it would help much, just a place for water to enter in, If the cavities are full of foam shouldn't be anywhere to ventilate.

CW

 

[ricohman]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

Ditto on 1/2" its just fine, I use it for all decks

Foam is acutally required and I wouldn't do a boat without it, helps add some stiffness to the structure as well. (2lb foam is fine)

Don't know about the ventilation idea, never seen it done, but don't see it would help much, just a place for water to enter in, If the cavities are full of foam shouldn't be anywhere to ventilate.

CW

Thats an interesting point and makes a lot of sense. I can see how pour in foam would help stiffen and reinforce an aluminum boat.
So, if you use pool noodles and such how much stifness are you losing? Does the deck feel as solid with the noodles?

 

[Cadwelder]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

Does the deck feel as solid with the noodles?

Nope, not at all.

 

[sledrescue]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

I went with 3/4" throughout my boat when I did the rebuilding and wish I would have stuck with 1/2" and saved some weight. Especially since I used foam and that adds ridgidity to the deck.

Foam will allways be a debate but I did use the pour foam on mine. Some will tell you that the foam adds to the destruction of the wood and if you use it, you'll need to do the whole job over again 28 years from now. Don't know of any great savings by using sheets or pool noodles to suplement the poured stuff. Just seems like extra work. I've heard of people using PVC tubing for leaving channels along the hull for drainage so that any water has a path to the bilge. That might not be a bad idea and could give you some piece of mind.

As far as regulations for flotation foam, I believe that only applies to manufacturers.

I think I will stick with the 1/2" plywood.

I also did give some thought to the PVC pipe and pour in foam on top of that to allow drainage to the bilge area. I am assuming that you fiberglassed in your plywood first and let that set up good and then cut a couple of holes with a hole saw to pour in the expandable foam and then inserted the plywood plug cores back down into the foam and then once the foam was setup then reinforced the plywood core with some fiberglass to seal it back up.

 

[Cadwelder]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

The PVC has been thrown around a lot here, problem is the pipe is a sealed unit, how does the water ever get inside it to drain?

Yep on the wooden plugs, personally I seal the raw plywood edges with epoxy and then just fill the dip in the foam with thicken resin (using MIRteq lately), let it cure and sand it down smooth to the deck and then glass over the hole. But it's fine either way...

If you choose to use the plug back, use thicken resin to set them back in so you get a good seal...

CW

 

[sledrescue]

Re: Floor/Deck replacement "To FOAM or Not to FOAM, this is the question?"

Thanks for the help guys.

I stopped at Express Composites in Minneapolis http://expresscomposites.com/ this afternoon and got set up with everything I needed for the project. Tomas and Josh were very helpful and are boat guys as well. These guys know their stuff.

I stopped at Menards this evening and picked up a fresh 4x8 sheet of 1/2" BCX Plywood. It is 4 ply versus the 3 ply they offered in a CDX.