Stupid pontoon questons

Discussion in 'Multihulls' started by inventing_man, Jun 17, 2007.

  1. inventing_man
    Joined: Jun 2007
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    inventing_man Junior Member

    Greetings!
    The question is why aren't pontoons made of aluminum or polypropolene..... foam filled or , at least lined ? It seems only logical to do so even if they are chambered . I know Foam adds weight , but not near the weight of a water logged chamber or two.
    Most Fiberglass bass boats are foam injected , so it cant be that much weight to add foam.
    Second stupid question . If the layout were correct and plenty of draft....and this and that.... etc.. could a jet pump be mounted INSIDE a pontoon with the intake grate mounted on bottom and function properly ? or would the curve tank play havoc causing cavation sucking air around the round tank ? What If it were a flat bottom pontoon?

    But like I said stupid pontoon questions :D
     
  2. alan white
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    alan white Senior Member

    Pontoon boats are really just rafts with motors. They began as a means to putt around the lake while having a BBQ. Like everything else, they developed ----like jeeps developed into mammoth SUVs with 500 hp.
    Like jetskis got bigger until they looked like small runabouts.
    I think a lot of the reason pontoon boats don't have foam flotation is because they are fair-weather craft that seldom if ever go out of sight of shore. It is inconceivable that a pontoon boat could lose flotation in both hulls at once, so there is already a large safety factor in addition to the near-shore limitation (I imagine one of these pontoon boats would be a nightmare in three foot seas!).
    Soon, however, someone will make a pontoon boat that has better hulls for deeper water. Then a few people will get themselves drowned and regulations will be imposed.
    As far as your other questions go, I suppose nobody who knew anything about going fast under control would consider modifying a pontoon boat to begin with. Jets in the hulls would be very possible, I'm sure, but if speed is what is wanted, and money no object, it would be kind of like putting rockets on the Goodyear blimp.

    Alan
     
  3. Bergalia
    Joined: Aug 2005
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    Bergalia Senior Member

    Stupid pontoon questions

    Actually no question is stupid. If it's something you are unsure of - it's a valid question, even though you sense it's been asked a dozen or more times before. It's just that you, personally, don't know the answer. And that's where this forum comes in with people like Alan who can give you the correct answers.
    Welcome aboard Inventing Man. No doubt you've got answers to our 'stupid questions...' And you can bet, sooner or later they will appear in these columns.:)
     
  4. inventing_man
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    inventing_man Junior Member

    Thank you for the welcome . I might be able to cast out a life ring now and then . The scope of a jet drive in a pontoon isn't for speed , its for safety and the ability to run shallow - ish. Tune the pump for torque not speed ..if that is do -able ...?
     
  5. alan white
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    alan white Senior Member

    That must be doable, but then what manner of scum and debris would be found at shallow depths to be sucked in?
    The Everglades boats solve this with air propellers. Noisy, to be sure. I'm not an expert in the jet drive area, but I believe there are some here who are fairly knowledgable.
    Good luck, I'm sure the answer will come your way.

    Alan
     
  6. inventing_man
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    inventing_man Junior Member

    Running shallow in not the main objective with this project . I should have stated that better . Pumps are known, and sought after for their ability to do this , and its good to bring this attribute into the overall design, but its not the focus.
    For my piece of mind a 3 inch foam lining inside the pontoon seems wise.
    I'm still uncertain of possible cavitation problems with a round tank ? I dont think it would be given a adequate draft .
     
  7. alan white
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    alan white Senior Member

    That would be beyond my knowledge to answer. Can I ask, is your idea to develop a marketable unit that adapts to an existing pontoon market? Just wondering how you're approaching this. What is practical on a mass market scale is not what's practical for one boat, nor are pontoons that sophisticated---- they depend on the cost benefit of using standard pipe sections easily adapted to one particular kind of boat used on protected waters.

    A.
     
  8. inventing_man
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    inventing_man Junior Member

    No, Its something totally different that combines to different markets. However if one segment does one , then they more than likely do the other ., or would do the other if their money was ok. This project can make it affordable to do both. Plus offers many other positive attributes you dont find in ether market separately. There are several makers of pontoon boat kits in all sizes . The pontoons themselves are readily avab, cost effective , sturdy, light weight. and adaptable . I might even add "trusted" to that list. That alone could play a considerable factor. It could be that after a proto type is built that it could go to a mold , layup process and forgo the pontoons all together.. To early to tell though. The main reason for jet pumps is the safety factor over props .
     
  9. snow 57
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    snow 57 Junior Member

    I have been trying to design a solid dinghy that has the shape of an inflatable for years. The first one was made from poly foam tubes 75mm thick glassed inside and out with epoxy resign. By the time it was solid enough to be servicably it was too heavy. The next was 3mm bending ply with a resign coat inside and glassed out. Weight for a 2m dinghy was 21kg and it was great till it got wet inside. After about 3 years service it got soft and died. Just this year I have built a strip plank one that is a little too heavy though unbreakable. Right now I am half way through the second strip one using the lightest glass I can get and holding back on the internal frames. So I guess what I'm saying is strip plank is my preferred material for this kind of project and if you are worried about flotation put in some dividers, the chances of holing many compartments is much smaller.Cheers Snow
     
  10. inventing_man
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    inventing_man Junior Member

    A possible solution could be to build a simple light weight skeleton frame to add strength . Use polyurethane foam directly onto the frame and build up your ruff shape . carve it out to shape and cover with rhino lining . top to bottom. It will not sink ...ever . Even blown to piece's , it all would float . :D
     
  11. stonebreaker
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    stonebreaker Senior Member


  12. inventing_man
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    inventing_man Junior Member

    Nice ! You would have to understand the concept . I'm holding that in reserve for now . But Soon I hope to pull the curtain back . An outboard motor would be in the way . I'm trying to gain some knowledge about some of the components that make up this project.
     
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