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Floatation Foam

Discussion in 'Boats and Motors' started by ducksdemise, Sep 20, 2004.

  1. What can I use for floatation foam?
    Spray, Rigid sheets etc.
    I have a 17' lonestar with no flotation in it.I want to fill the floor with foam.
    Any ideas will be appreciated.
  2. Fish4Fun

    Fish4Fun Relaxing.

    i wounder if the 4x8 sheets of foam board would work

  3. mrfishohio

    mrfishohio Recovering Fishaholic

    I think most factories do a spray in. Lakeraider does alot of boat work, he'd probably know. I had a Skeeter that had a channel in the middle for drains & also hoses & wires to run thru, then both sides of it were foam filled. My Starcraft has big foam pieces pushed up in the gunwales. I think they were factory installed, they are not spray-in, they are just big cut pieces.
    I know I had some insulation foam in a can I used years ago on a house project, it expands alot after you use it, so be sure to allow for expansion if you use a product similar to it. You might also call up a boat dealership and ask them what they use. I'm sure they do insurance repairs from time to time.
  4. You have several options to choose from, each having some advantages and disadvantages. You can use sheets available locally, solid billets, and two part pour in foam. DO NOT use the spray foam in the aerosol cans.

    The two part expanding foam is used in most new boats. It fills all of the nooks and crannies beneath the floor which is great for adding support to the hull and floor but it also will not allow drainage if water gets beneath the floor. Some manufacturers may provide drainage channels but my Sea Nymph that I'm currently running was made with expanding foam and the foam blocked the drainage gaps beneath the ribs. When the boat developed leaks the water would lay beneath the floor for quite awhile before it drained. Eventually the foam became saturated with water and added 250 lbs to the weight of the boat. I found this out when I removed the floors and dug the wet crap out.

    Sheets and billets will allow enough space beneath them for drainage but they may be harder to install. You will have a lot of waste trying to trim the pieces to fit the irregular areas beneath the floor. You will have to remove the floor to install the solid foam. Also, depending what you use to cut the foam it may feel like dragging your fingernails down a chalkboard.

    When I rebuilt the Sea Nymph I used the white 2" thick foam boards available at Home Depot. The white foam is very similar to the foam I removed from my current Starcraft project boat except the grain is finer. The 1970 Starcraft I own had large blocks of white foam with a very coarse grain or bead size. It was 33 years old when I removed it and some had disintegrated but none was waterlogged and the boat sat outside uncovered for at least 6 years. For the Starcraft redesign/rebuild I plan on using sheets for the majority of the floatation under the floor with the addition of some expanding foam above the sheets and below the flooring to fill the irregular areas. I may also add some along the gunwales although none was there originally.
  5. If you choose to use expanding foam you can install it without removing your floor. If you know where all of your floor supports are you can use a hole saw to cut 2 or 3" plugs in each chamber area. Tilt the boat so the liquid flows downward and fill each chamber with several small batches until nearly full. As you do the last pour in each section, place the plug in the hole and weight it down with a brick. After curing, glass over the plug with either epoxy or poly resin.
  6. Doctor

    Doctor CJ Cat Attack Pack

    My old Sea Nymph had the same problem as Ken G, it had some rivit leaks the water got under the floor and it soaked it up like a sponge, it was a winter project for me I tore out all the flooring and carpet, fixed all the bad rivits, added a drain channel along the ribs, then installed new marine grade plywood, then I took it up to the Sea Nymph factory in Indiana and for $204.00 they injected foam that wouldn't absorb water or gas, it was great, the boat floated so much higher and made a lot less noise than before.

    I know some guys on another board are cutting out the foam from sheets and placing it between the ribs. and putting the floor down on top of it, some floatation better than nothing........Doc
  7. Check out the forums at Iboats, in the project boats sections. There's been tons of discussion on floatation there. Both on what you can use, and what NOT to use.
  8. freyedknot

    freyedknot useless poster

    ask tony at
  9. LakeRaider

    LakeRaider EEEEEK!

    I go with KenG on this one. They used the expanding foam on my new G3 and it blocked off most of the drain areas in the floor section of the hull. If I hadn't pulled up the floors in the boat last fall (while running wiring) and found the trapped water I would have had a destoyed brand new boat. (trapped freezing water= POPPED HULL). If you can get to the gunnels add your floatation in that area. That will help with nuetral buoyancy. I had a very in depth conversation with Ken Warby on this subject, trying to make a 10Ft. boat float a 90hp. motor. The hull is the floatation devise(persay) anything else (added foam etc.) IN THE HULL,only gives the boat nuetral flotation capabilities.(AKA- SUNK) In other words, to make the boat float more weight the foam (etc.) would have to be under the hull. Any added floatation in the hull (gunnel areas etc.) will only give the boat nuetral floatation. Which I beleave is what you are looking for. KenG, you know where I,m going on this one, bring them up to speed! :cool: Somebody put too many olives in my martunies tonite! ;) Later, Raider (.)(.) Burf!

    Floatation devise! Bwahahahahah!

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