how to dry out the foam

[Melvin1234]

I have about a 6 inch gash in the hull of my boat and it has takin on a fair amount of water. I have drained all that I can but I need advise on how to dry out the saturated foam inside the hull, any ideas on how to attack this? Gash is approx 1" x 6"

 

[ondarvr]

Re: how to dry out the foam

If the damage was done recently and the water wasn't in there for long it shouldn't be very wet, but if it has been there for a long time then a great deal of foam could be soaked. Drying soaked foam isn't going to work very well, it can take a long time and the foam has been degraded or it wouldn't have absorbed the water. You can dig it out and replace it though.

 

[Woodonglass]

Re: how to dry out the foam

Pics really help us to help you. ondarvr is "Spot On" about the foam. If it's only been exposed to water for a short period of time then a shop vac and fans and a few weeks of open time should do the trick. If it's been a few months then you may need to replace it. Where's the gash located? Again Pics will tell the tale. Open a Free Photobucket account, upload your pics and then use the IMG Code to copy and paste your pics into this thread. You'll get a lot of help once the pics are posted.

 

[Melvin1234]

Re: how to dry out the foam





The first photo is on deck and the opening is about 3 1/2" x 6" and the gash underneath is about 1" x 6"
Hope the photos worked?

 

[Woodonglass]

Re: how to dry out the foam

Again, how long was the foam exposed to water? What kind of boat is this?

 

[Melvin1234]

Re: how to dry out the foam

Quite some time I fear but I'm not certain, and the beast is a 77' thunderbird.

 

[Woodonglass]

Re: how to dry out the foam

If its been "quite some time" then I'm sorry to say, there's actually very little chance you'll be able to get the foam to "give up" the water in a timely manner. Your only way to restore the boat is to remove the deck, dig out all the waterlogged foam, repair the hull both inside and out, and replace the foam and deck. That's really the only reliable way.

 

[500dollar744ti]

Re: how to dry out the foam

How did the gash get there? It looks like it's already in a place where a repair (attempt) was made..

 

[Melvin1234]

Re: how to dry out the foam

It happened one night trying to load the boat on a rough lake

 

[500dollar744ti]

Re: how to dry out the foam

I just dealt with repairing a hole in my boat. I would be grinding out that whole area, it looks like it was repaired horribly in the past and you can't keep putting bandaids on that spot.

Woodonglass was very helpful and there's a video on youtube called "there's a hole in my boat" that has 3 parts. The guy does a great job of explaining how to repair a hole and how to do it right.

Your boat looks like it may be a Boston Whaler but it's hard to tell from the pictures. I would still grind away at the attempted repair and try to fix the whole thing right.

 

[Scott Danforth]

Re: how to dry out the foam

here are the steps to drying out foam:

cut out floor
dig out wet foam and dispose of
replace rotten stringers and transom
fix hull, stringers, transom
pour in new foam
tab in new floor

 

[jigngrub]

Re: how to dry out the foam

here are the steps to drying out foam:

cut out floor
dig out wet foam and dispose of
replace rotten stringers and transom
fix hull, stringers, transom
pour in new foam
tab in new floor

^^^^ That's pretty much it!^^^^

Once the foam has become saturated it is ruined. Even if the surface of the foam dries out the core will still remain wet and the foam will absorb more water when it comes into contact with it.

 

[Ike-110722]

Re: how to dry out the foam

Unfortunately, they are all right. This looks like the foam needs to be replaced. I have seen a lot of boats with saturate foam and it is darn near impossible to dry it out and even if you do it is no longer "closed cell" and useless as flotation.

replace it. But I would use block foam (pre-made) rather than two part pour foam.

 

[Melvin1234]

Re: how to dry out the foam

The vessel is a 1977 thunder Bird tri hull any advise on how to attack, does the whole floor have to come out our can I just cut out ,strips to get to the foam?

 

[Woodonglass]

Re: how to dry out the foam

It would be a lot easier to remove the entire floor. How long would you say this gash had been allowing water into the hull? How long have you had the boat? If the foam is totally waterlogged then once it's been removed there's a very good chance you'll find that the stringer, bulkheads and transom will be wet and rotting and need to be replaced as well. Boats of this vintage usually turn out to be full blown restorations that can run from $1-3K in costs to restore. Just so you're aware.

 

[Ike-110722]

Re: how to dry out the foam

It would be easier in the long run to just take it all out and replace it. I did what you are asking, cutting away a little at a time, but in the end I had to replace almost everything anyway on my 1972 Sea Ray. Most of the wood was rotted away, and all of the foam was water saturated. 36 years is a long time in a boat's life. It would be better for the boat if you replaced it all. The only part left when I was done was where the engine bed is and the wood was sound, but then I had to tie the new structure in by bolting it to the old, and it just wasn't worth it. It would have been easier to remove the engine and replace it all making it one continuous grid under the deck.

 

[Melvin1234]

Re: how to dry out the foam

I've cut away most of the floor and have removed about half of the foam so far. I'd say about 600 lbs worth. "Totally soaked"
What is the best replacement foam to use?
I've been hearing a lot about block foam lately.

 

[jigngrub]

Re: how to dry out the foam

For a tri-hull you really need the 2 part expanding urethane foam, it'll help support your deck and hull and it also fills all voids to displace water.

Check your transom, stringers, and bulkheads for rot by drill 1/4"-3/8" holes in them down low. If the shaving are dark and damp your wood is rotten and you need to replace them.

Do you have a handle on how you're going to repair that nasty gash?

 

[Melvin1234]

Re: how to dry out the foam

Any idea on how to figure how much 2 part I would need? The gash has since been repaired by 2 layers of mat glass followed by 2 layers of cloth on both sides.

 

[Ike-110722]

Re: how to dry out the foam

If you use pour foam read the instructions thoroughly and carefully first. They will tell you how much it takes to make one cubic foot of foam. Then you need to figure out how many cubic feet you need. Of course the other way is just to mix it up and pour it in and see how much it foams up. That is how most people screw up when using this stuff. Many people think pour foam is easy to use. Just mix it in a bucket and pour it in. But it is subject to a lot of variable. It use what is called an exothermic reaction. When you mix the two parts they generate heat which makes the stuff foam up. If it gets too hot it foams too rapidly and breaks the little bubbles (the cells) and is no longer closed cell foam. It will absorb water. If it doesn't get hot enough it doesn't foam and makes what looks like cow pies or bread dough. It is also sensitive to ambient temperature and humidity, and dirt. Make sure you mix it in a clean container. If you do it right according to the manufacturers instructions you get nice 2 lb density foam.

This is why I advocate using block foam. Yes, it is hard to cut the blocks to fit the shape of a tri hull. And it is hard to find polyurethane foam in block. So I just use polystyrene. No it's not styrofoam. But I encase the foam in a polyvinyl bag or in fiberglass and epoxy so nothing can get to it. The problem with polystyrene is it will be attacked by gasoline, oils, bilge cleaners, just about any petroleum or caustic substance. Polyurethanes aren't attacked by these. So if you use polystyrene you have to protect them. Polyvinyl plastic sheet, which you can buy anywhere, isn't affected by these. Epoxy won't even stick to it. See here how I did it on my Sea Ray. New Boatbuilders Home Page - Projects - 1972 Sea Ray 190 Rebirth You can buy this stuff in 2 foot by 8 foot sheets at any Home Depot or Lowes in 2 inch or 4 inch thick. One sheet of the 2 inch is 2.25 cubic feet. It is either pink or blue depending on the brand. I have seen it in white.

They also sell styrofoam sheets so be careful. The difference is styrofoam has much bigger cells, so it is not as dense, and it is easily damaged and tends to break down rapidly into those very familiar little white balls we all see floating in the water. It has it's uses but it is not as good as the polystyrene (some will say styrofoam is polystyrene. Yes it is but it's a brand name like Xerox, and made differently whereas polystyrene is the substance it's made of and a generic term)