Foam pontoons?

Discussion in 'Boat Design' started by Ron Skelly, Feb 27, 2014.

  1. joebehr
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    joebehr Junior Member

    Keep in mind that my pontoon boat is mainly for fishing...only 13' long and only goes 9-10 mph w/ a 15 merc. My main concern was better flotation for walking around the deck and that it would not plow water with two people in the front seats. Not sure foam pontoons would handle the stress of high speed or banging into waves, but the increased flotation is perfect in my application. I built an 18"x18"x96" center pontoon including the West System epoxy resin and mounting hardware for under $300. My only option was to purchase poly pontoon for around $800 so I decided to try my hand at making my own.
     
  2. joebehr
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    joebehr Junior Member

    Here are a few pix of the foam pontoon in the early stages to give you more insight.
     

    Attached Files:

  3. Russ Kaiser
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    Russ Kaiser Exuberant Amateur

    Fishing Platform?

    Ron, how wide are you planning on making this and how many adults are going to fish from it? You gave a length of 13 feet.

    Is it going to live in the water, or are you going to launch it each time?
     
  4. upchurchmr
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    upchurchmr Senior Member

    Ron,

    You really don't need fiberglass. :D
    Actually I don't like the rear support for the chair, and the bow and stern could be shaped better, but other than that???

    [​IMG]
     
  5. Russ Kaiser
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    Russ Kaiser Exuberant Amateur

    I didn't know Bama had an Aerospace and Oceanographic Engineering Department! This well designed craft can go straight from the lake to the "found art" exhibit. BTW, where's the flippin' cooler?
     
  6. upchurchmr
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    upchurchmr Senior Member

    He didn't make it 13' so he didn't have room, unless it was shoved into an inner tube and towed.

    Any way lots of guys are looking for a minimum cost boat.
    Bolger just didn't go far enough. :p
     
  7. joebehr
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    joebehr Junior Member

    Just a few notes on my eps foam pontoon. My boat is slow so there's not much stress on it or the new pontoon. I coated it twice with epoxy resin to seal it and for a hard surface. If you're building a boat from scratch three foam pontoon will float a bunch of weight. The capacity of my 18"x18"x8' pontoon is 500 lbs at 1/2 submerged. When in the water my boat draws less water by 3" from before.
     
  8. upchurchmr
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    upchurchmr Senior Member

    How much did the eps foam pontoon weight?
    foam gets heavier that making a plywood box in a large size.
     
  9. joebehr
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    joebehr Junior Member

    Mine weighs about 35 lbs including everything
     
  10. upchurchmr
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    upchurchmr Senior Member

    That's not bad, don't know that I could beat it.
     
  11. joebehr
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    joebehr Junior Member

    I used 1.5 lb per cu ft EPS foam for my pontoon...it floats 60 lbs per cu ft in fresh water...that is 60 lbs to totally submerse the cu ft block of foam. Always calculate flotation at 50% so your pontoon has 1/2 free board...that's a relatively safe guideline. If you had a boat with two 14' pontoons and a 10' center pontoon and all three were 18"x18" the capacity would be 2565 lbs at 50% free board or half submerged...that's a lot of capacity and the 3 pontoons might total 200 lbs if that much.
     
  12. joebehr
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    joebehr Junior Member

    Oh...my boat stays in the water all summer and if the foam is well sealed with epoxy resin the extended time in the water is no problem and since my foam pontoon is completely hidden from the sun, there was no need to use a UV paint...it never see the sunshine.
     
  13. joebehr
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    joebehr Junior Member

    foam 3rd pontoon

    So after several outings on the boat after mounting the 3rd center foam pontoon, I have some changes to make. First, the pontoon itself works very well but the position/location is not correct. It needs to be moved all the way forward, at least even with the other two, maybe even out in front a bit. The problem is I have a bow mounted trolling motor centered in the front of the deck. So, I've decided to remove the foam pontoon, cut it in 1/2 down the center vertically and mount the halves next to the inside of the 2 aluminum toons and all the way out front. This way I keep the added flotation and moving forward raises the bow more. With the foam toon in the center and in the water all the time I have raised the center of gravity some to the point that it is very easy to stuff the front of the deck in the water if I cut the throttle abruptly...
     
  14. joebehr
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    joebehr Junior Member

    still looking for mor flotation in the bow.

    Still fussing around with my 3rd pontoon for my 13' gillgetter...thinking of splitting my 18
    ' square pontoon in half length wise and mounting the two sections just inboard of the original pontoons in order to allow me to move the added foam floats all the way to the front for better flotation where I really need it. Has anyone done this? Add to the inside of the original two instead of in the center?
     

  15. HJS
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    HJS Member

    Polyester on polystyrene foam

    I have built several test boats in polystyrene foam, insulated with wallpaper adhesive for wet rooms and plastic-coated fiberglass with polyester on the outside. It's the absolut cheapest way to build a boat.

    js
     
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