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  • replacing boat foam

    So I am looking to pull the foam up from the boat and replace it. My question is this.
    Closed foam if I go that route, where in Anchorage could I purchase it?
    Flotation foam the same thing? Looking for any suggestion and good and bad points.
    This is going to be a pain and I can imagine how much this is going to weigh. I would like to put in foam that is waterproof. Or If I need to wrap it in a sealant bag.

    Living the Alaskan Dream
    Gary Keller
    Anchorage, AK

  • #2
    Not sure how big your boat is. Mine is a 21ft Jetcraft. I chose the hillbilly bushcraft solution when I decided to tackle this same issue last year. I took up the floors and scraped all the water-logged foam out and filled all my under floor voids with pool noodles. You get some funny looks at walmart when you are buying 100+ pool noodles, but its worth it. Just remember to wear your white tank top, cut off shorts and sunglasses.

    Fun times, but really I did actually use pool noodles. It was a pretty inexpensive solution and I'm happy with the results. My boat is much lighter and the noodles were easy to cut and insert.

    Comment


    • #3
      Originally posted by KantishnaCabin View Post
      Not sure how big your boat is. Mine is a 21ft Jetcraft. I chose the hillbilly bushcraft solution when I decided to tackle this same issue last year. I took up the floors and scraped all the water-logged foam out and filled all my under floor voids with pool noodles. You get some funny looks at walmart when you are buying 100+ pool noodles, but its worth it. Just remember to wear your white tank top, cut off shorts and sunglasses.

      Fun times, but really I did actually use pool noodles. It was a pretty inexpensive solution and I'm happy with the results. My boat is much lighter and the noodles were easy to cut and insert.
      I have a 26-foot boat. Think I will need to clean a few Wal mart out
      Living the Alaskan Dream
      Gary Keller
      Anchorage, AK

      Comment


      • #4
        I used white closed cell dock foam. I got mine in 2, 4 X 8 X 1 foot thick pieces and cut them to fit. I got mine for free from a buddy that got some surplus stuff at an Akieska auction.

        Comment


        • #5
          Originally posted by mark knapp View Post
          I used white closed cell dock foam. I got mine in 2, 4 X 8 X 1 foot thick pieces and cut them to fit. I got mine for free from a buddy that got some surplus stuff at an Akieska auction.
          <br/><br/>Thatís good stuff because it doesnít soak. The Coast Guard hates it in a hull because gasoline eats it immediately. At least thatís what the guy who built my boat told me.

          Comment


          • #6
            Originally posted by Alaska Gray View Post

            I have a 26-foot boat. Think I will need to clean a few Wal mart out
            If you're determined to put foam back in there, then pool noodles are going to be your most practical, cost effective option. Extruded polystyrene (XPS) (commonly known as "blue board" or "pink board" in Alaska); expanded polystyrene (EPS) (white molded product consisting of little beads of white foam, commonly used for cheap coolers, insulation board, dock floats, etc.); as well as any of the poured or sprayed foam products commonly used all absorb and retain water over time. Closed cell extruded polyethylene foam is what you want, and pool noodles is the least expensive, most cost effective form of it by volume that you're going to find. Sourcing it in sheet form is a lot more expensive.
            ...he who knows nothing is nearer to truth than he whose mind is filled with falsehoods & errors. ~Thomas Jefferson
            I would rather have a mind opened by wonder than one closed by belief. ~Gerry Spence
            The last thing Alaska needs is another bigot. ~member Catch It

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            • #7
              Originally posted by mark knapp View Post
              I used white closed cell dock foam. I got mine in 2, 4 X 8 X 1 foot thick pieces and cut them to fit. I got mine for free from a buddy that got some surplus stuff at an Akieska auction.
              This is a good method if you are set on putting foam back in, reasonably affordable and you can replace it easily if it does absorb water. The pour in foam is supposed to not absorb water, however there are many, many threads on this very subject, why are you putting the foam back in?
              “Ideologies separate us. Dreams and anguish bring us together.”
              ― Eugene Ionesco
              "FREEDOM" Only those that are denied truly know what it means.

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              • #8
                Originally posted by Akgramps View Post

                This is a good method if you are set on putting foam back in, reasonably affordable and you can replace it easily if it does absorb water. The pour in foam is supposed to not absorb water, however there are many, many threads on this very subject, why are you putting the foam back in?
                It helps quiet the boat down some. And, in my mind, if my fuel tanks aren't completely full (empty tanks help some), I'm thinking it might help float the boat some if I don't incur a complete swamping from a rogue wave. It would give my high volume bilge pump a chance to get some water out before the next wave hit, maybe help me save the boat. It's wasted space anyway. Sinking is variable not all-or-nothing. Some flotation is better than nothing.

                I have seen dock foam on 20 year old docks that were only sitting a half inch lower in the water than when it was first put in. My original spray-in foam weighed 423 pounds when I took it out. I have been told that all pour-in or spray-in foams absorb water. I have no way of knowing for sure.
                Last edited by mark knapp; 03-30-2021, 12:03.

                Comment


                • #9
                  Originally posted by Alaska Gray View Post
                  So I am looking to pull the foam up from the boat and replace it. My question is this.
                  Closed foam if I go that route, where in Anchorage could I purchase it?
                  Flotation foam the same thing? Looking for any suggestion and good and bad points.
                  This is going to be a pain and I can imagine how much this is going to weigh. I would like to put in foam that is waterproof. Or If I need to wrap it in a sealant bag.
                  Gary

                  The time to take the foam out is while it is frozen. It comes out in bigger chunks & does not smell near as special as it does when thawed & dripping with fish gurry....................... Clam shovels work real good for digging it out too. I used pink board from SBS to replace the old stuff in my old searunner.
                  2007 24ft NorthRiver OS
                  Twin 175 Suzuki's
                  "Thunderbird"
                  MMSI #338033856

                  Comment


                  • #10
                    So I went through this process a couple years ago. And being an engineer, I did a fair bit of research, so apologies in advance for a wall of text. I'm also familiar with foam board specs as I use it for insulation in below-grade or buried conditions, so absorption specs are important depending on conditions. Here's what I can tell you:
                    • The foam in boats is closed-cell polyurethane. It's typically a two part product that should be installed in perfect atmospheric conditions, like 70F, etc. This is critical or your foam turns out of spec and might not even be closed cell or the right density, etc (hence boat foam that saturates).
                    • I looked but did not find a one part product that was properly closed cell or fuel resistant.
                    • Foam boards in your hardware store can vary, but the name brand EPS and XPS products should have specs available from the manufacturer (Pink, Blue, Insulfoam, etc). These products are typically closed-cell and should have relatively low water absorption submerged, 0.3% or less is a common standard for XPS (extruded). I'd probably avoid EPS (expanded foam, white little balls), but good engineered EPS foam runs around 2-4% absorption by volume which is only knocks a couple pounds of buoyancy off per cubic foot (eg 57 pcf of buoyancy vs 60).
                    • Generally, the foam boards in your hardware store are not polyurethane and are susceptible to fuel or petroleum spills. You can order polyurethane foam boards, but they are spendy and not sure if you can get them locally.
                    • We do have a local foam manufacturer, last I checked, Insulfoam. No idea if they will sell direct, but they sell both EPS and XPS. Just watch the product specs if you're worried about it.
                    • Two-part polyurethane foam in 1 gallon containers can be bought from West Marine maybe others. It's a 2 lb density product, ~$50+ for a gallon or two if mixed. I found some in stock, but limited supply.
                    • Two-part polyurethane foam can be bought in large kits with spray nozzles from SBS and perhaps others. Just be sure it's mixing it correctly to properly harden and run some tests. Google says a kit similar to what I used now runs $850 at Ace Hardware, it appears to have gone up since a couple years ago. I checked it and looks like the same specs or similar product as the pour foam, but do your own research. It's spendy, but it sure goes a lot quicker and does good coverage.
                    For my installation, I calculated the volume that would be foamed in below the floor. With 2-lb foam (2 lbs per cubic foot), if the foam is submersed you should get about 60 lbs of buoyancy per cubic foot of volume. I made sure the buoyancy was distributed across the boat and exceeded my boat's estimated weight. You can get into the weeds on this, and I probably did (specific gravity of aluminum and effective weight submerged, etc). I also refurbished the fuel tank venting so air and fuel should stay in the tanks if submerged.

                    I used aluminum primer before placing foam to reduce the chance of poor bonding or crevice corrosion in case water infiltrated past the foam. I used the 2-lb West Marine foam in the bow, but it was slow and went through the gallon or so quickly. The advantage is you can mix it very accurately, which creates consistent foam. I also preheated the hull just to get it up to 70-80F degrees. It's hard to get 70F days in Anchorage.

                    For most of the boat, I used the two-part, closed-cell polyurethane spray foam. To make the product go further since it's so expensive, I sprayed a layer of foam against the hull and stringers. Then immediately installed pink board and foamed over it to encapsulate it. This way fuel or oil has little chance of getting to the pink board. I also sealed the aluminum flooring very well on every seam. For those with tanks in the floor, I'd suggest looking at some of the USCG requirements or ABYC standards as I don't think they recommend or allow foaming fuel tanks in place likely due to crevice corrosion (water against the tanks with no oxygen = aluminum corrosion) on the tanks.

                    Some benefits after foaming, the hull is much quieter when running. There is also some structure against the hull to help keep it from deflecting. Probably won't leak with a small hull-puncturing rock strike. There's a good chance the hull won't sink to the bottom, but hard to say without testing it (not going to do that!). I'm tempted to put emergency valves on the fuel vent lines (they should air lock unless the engine drags it down too far), as 70 gallons of fuel tank, full to empty is another 150-600 lbs of buoyancy assuming the fuel/air stays in the tank. I'm also careful to not let the boat collect water during the off season to avoid letting water infiltrate into or around the foam.

                    Anyways, it's a lot of work and hopefully I never have to weld on the hull again. It may be easier to just invest in a life raft and a large bilge pump with good maintenance if your boat didn't have foam to begin with.

                    Comment


                    • #11
                      Originally posted by JEH97LX View Post
                      So I went through this process a couple years ago. And being an engineer, I did a fair bit of research, so apologies in advance for a wall of text. I'm also familiar with foam board specs as I use it for insulation in below-grade or buried conditions, so absorption specs are important depending on conditions. Here's what I can tell you:
                      • The foam in boats is closed-cell polyurethane. It's typically a two part product that should be installed in perfect atmospheric conditions, like 70F, etc. This is critical or your foam turns out of spec and might not even be closed cell or the right density, etc (hence boat foam that saturates).
                      • I looked but did not find a one part product that was properly closed cell or fuel resistant.
                      • Foam boards in your hardware store can vary, but the name brand EPS and XPS products should have specs available from the manufacturer (Pink, Blue, Insulfoam, etc). These products are typically closed-cell and should have relatively low water absorption submerged, 0.3% or less is a common standard for XPS (extruded). I'd probably avoid EPS (expanded foam, white little balls), but good engineered EPS foam runs around 2-4% absorption by volume which is only knocks a couple pounds of buoyancy off per cubic foot (eg 57 pcf of buoyancy vs 60).
                      • Generally, the foam boards in your hardware store are not polyurethane and are susceptible to fuel or petroleum spills. You can order polyurethane foam boards, but they are spendy and not sure if you can get them locally.
                      • We do have a local foam manufacturer, last I checked, Insulfoam. No idea if they will sell direct, but they sell both EPS and XPS. Just watch the product specs if you're worried about it.
                      • Two-part polyurethane foam in 1 gallon containers can be bought from West Marine maybe others. It's a 2 lb density product, ~$50+ for a gallon or two if mixed. I found some in stock, but limited supply.
                      • Two-part polyurethane foam can be bought in large kits with spray nozzles from SBS and perhaps others. Just be sure it's mixing it correctly to properly harden and run some tests. Google says a kit similar to what I used now runs $850 at Ace Hardware, it appears to have gone up since a couple years ago. I checked it and looks like the same specs or similar product as the pour foam, but do your own research. It's spendy, but it sure goes a lot quicker and does good coverage.
                      For my installation, I calculated the volume that would be foamed in below the floor. With 2-lb foam (2 lbs per cubic foot), if the foam is submersed you should get about 60 lbs of buoyancy per cubic foot of volume. I made sure the buoyancy was distributed across the boat and exceeded my boat's estimated weight. You can get into the weeds on this, and I probably did (specific gravity of aluminum and effective weight submerged, etc). I also refurbished the fuel tank venting so air and fuel should stay in the tanks if submerged.

                      I used aluminum primer before placing foam to reduce the chance of poor bonding or crevice corrosion in case water infiltrated past the foam. I used the 2-lb West Marine foam in the bow, but it was slow and went through the gallon or so quickly. The advantage is you can mix it very accurately, which creates consistent foam. I also preheated the hull just to get it up to 70-80F degrees. It's hard to get 70F days in Anchorage.

                      For most of the boat, I used the two-part, closed-cell polyurethane spray foam. To make the product go further since it's so expensive, I sprayed a layer of foam against the hull and stringers. Then immediately installed pink board and foamed over it to encapsulate it. This way fuel or oil has little chance of getting to the pink board. I also sealed the aluminum flooring very well on every seam. For those with tanks in the floor, I'd suggest looking at some of the USCG requirements or ABYC standards as I don't think they recommend or allow foaming fuel tanks in place likely due to crevice corrosion (water against the tanks with no oxygen = aluminum corrosion) on the tanks.

                      Some benefits after foaming, the hull is much quieter when running. There is also some structure against the hull to help keep it from deflecting. Probably won't leak with a small hull-puncturing rock strike. There's a good chance the hull won't sink to the bottom, but hard to say without testing it (not going to do that!). I'm tempted to put emergency valves on the fuel vent lines (they should air lock unless the engine drags it down too far), as 70 gallons of fuel tank, full to empty is another 150-600 lbs of buoyancy assuming the fuel/air stays in the tank. I'm also careful to not let the boat collect water during the off season to avoid letting water infiltrate into or around the foam.

                      Anyways, it's a lot of work and hopefully I never have to weld on the hull again. It may be easier to just invest in a life raft and a large bilge pump with good maintenance if your boat didn't have foam to begin with.
                      Good information, thanks.

                      Comment

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