Replacing flotation foam

[bob844]

I'm rebuilding an older bass boat for my son; basically replacing the floor. After pulling up some of the rotten plywood I found all the flotation foam was saturated with water. What can I replace it with that won't absorb water? This stuff appears to have been injected after the original floor was installed. I've been thinking of
getting foam boards at the Borg and cutting it into pieces to be fit into the areas where the original foam was.

 

[Woodonglass]

The Newer Pour In foam is better than what you're looking at. It won't waterlog. You can use the Pink or Blue slab foam from the big box stores too! It's totally up to you. Have you core sampled the stringers and Transom?

 

[sheboyganjohn]

Friscoboater on Youtube has some good video about pouring in foam in his Sea Ray rebuild. I like his videos because he is a every day Joe like us making videos as he is learning and perfecting the same things we are doing.

 

[DeepBlue2010]

I would stick to two parts pour in foam if I were you. The impact resistance of it - and as a result, the structural support it provides - is not comparable to its alternatives.

No major caveats, straight forward process really. Estimate the volume of the compartment you want to fill using math or if it will get complicated, by pouring in water from known volumes. It is the same way we measure the cc of the combustion chamber of a cylinder head. Wait for a day, and specific time of day, that match at least yhe minimum recommend temperature by the manufacturing.

Prepare a mixing attachment on a drill and make a good use of it since good mixing is a key to successfull foaming.

If you measured your volume accurately, you can get away with one fill hole per compartment. If you want to be on the safe side and dont mind drilling a little more holes in the new deck, go for two holes per compartment and fill from the deep side and wait for the overflow from the shallow side (if applicable)

Mask off anything you dont want to clean and be ready with plenty of cleaning supplies and Acetone. This thing goes everywhere specifically where you dont want it. Best of luck

 

[bob844]

I'm kind of wary of the pour-in stuff because that's what I dug out and it was completely soaked- had to be many gallons of water.
The stringers seem OK but I'm fairly sure the transom needs attention and I haven't even given it much thought while working on the floor.

 

[jbcurt00]

I'd be surprised the stringers are good, w a bad deck (floor) and transom, but perhaps.

The problem isnt the pour in foam, its careless maintenance/upkeep and neglect by previous owners that probably didnt know any better.

Once the water got below decks, it was only a matter of time......

Bow high, well covered (or stored inside) and ventilated w the drain plug out after every trip could have prevented all the rot and soft spots you've found.

 

[DeepBlue2010]

I'm kind of wary of the pour-in stuff because that's what I dug out and it was completely soaked- had to be many gallons of water.
The stringers seem OK but I'm fairly sure the transom needs attention and I haven't even given it much thought while working on the floor.

This is like saying "I will never use a knife for the rest of my life because my neighbor cut his hands using one"

As JB indicted, it is not the foam, it is how much work and care was put in the boat by POs.

How did you inspect the stringers? Did you take core samples?

 

[tpenfield]

The foam absorbed water only after many years of neglect. The foam does not readily absorb water. Go ahead and test some if you like. The key benefit to using the pour-in foam versus foam boards is that the pour in foam adds lots and lots of strength to the boat.

Who wants to ride around in a flimsy boat? :noidea:

 

[Twainer]

I went the Red Neck Route & used "Great Stuff" can spray foam. Seams like when I did mine there were all kinds of other items I would have to buy with the pour in foam that was only going to get used once. This great stuff is supposed to be closed cell foam & I didn't feel like it cost that much more. I have been spraying that stuff in every little crevis that is not seen & that does not need access in the future. The boat didn't really have that much when I opened her up but I filled everything below the floor only leaving room for water to travel to the back if it ever did get a leak.

 

[Woodonglass]

If you foamed the entire cavity under the floor with Great Stuff, you spent about 4 times more than what the pour in costs!!!! It's NOT as waterproof as the Pour In foam. It's not as dense when cured. Basically not a good method for foaming the hull of your boat. Sorry to rain on your parade but this topic has been discussed Ad Infinitum on the forum and general concensus is that it's not the way to go. However everyone has the right to do what they see fit with their boat.