jet powered canoe

Discussion in 'Boat Design' started by muskymania, Nov 11, 2012.

  1. muskymania
    Joined: Nov 2012
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    Location: TN

    muskymania Junior Member

    Im looking for any advice anyone can give me on my new build idea. Basically what I'm wanting to do is put a jet ski motor into a canoe so I can run upstream through rough water and fish my way back down. The materials I've looked at are Royalex and polyethelene. I was thinking I would have to some how have to cut the back off some so I would have a place for the jet to come out the back. Any ideas of how to seal up a multi layer canoe if I were to do this? I've seen people that will melt a wire screen into a canoe that has a hole and then melt more poly over the screen, but couldnt find anything about doing a transom.
     
  2. Submarine Tom

    Submarine Tom Previous Member

    YouTube has some good action shots of such.

    A wee bit over-powered however...
     
  3. muskymania
    Joined: Nov 2012
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    Location: TN

    muskymania Junior Member

    Yeah I saw that video but it wasn't infomative at all. I'm hoping to have more of a plan, not just slapping a big motor into a boat and hanging on for dear life.
     
  4. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Which rivers in TN? The Mississippi is a bit different than the Little Pigeon. I went damn near anywhere with a 2.5 HP hooked to a sidemount bracket. 16' for one person, 17' for two. Will want about 4 hp. for two people. Forget the jetski drive. I've never seen one small enough. I would look for a lake canoe with a full length keel. I used a three blade al prop intended for a 6hp motor. I could go about 200 miles at 4 knots on a 6 gal tank with 700# payload, or could scoot along on a plane if lightly loaded. You're not going to go fast enough to take advantage of a jet drive. A puny outboard is so much simpler. If you want to blast upsteam through class three rapids and over strainers, a canoe isn't really the thing. If you want something light enough to drag over the occasional strainer and portage around the odd rapid or dam- it's perfect.
     
  5. muskymania
    Joined: Nov 2012
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    muskymania Junior Member

    I don't really want to give away my specific location but I was looking at something like a 14-15 canoe. It has to be a jet because alot of the water I would be using it in would be fast moving shallow water with lots of rocks (class II-III rapids) I was looking at using a kawasaki 300cc cause I dont need tons of power and want to keep weight down. There is a brand of jet kayak out there called mokai so I sure think it can be done, I just want something slightly larger with a stronger hull.
     
  6. Submarine Tom

    Submarine Tom Previous Member

    There's an old, traditional way we do it here called a paddle.

    Two paddlers, some strategy and experience and you can get around pretty well.

    Very likely not what you had in mind though.

    Best of luck.
     
  7. muskymania
    Joined: Nov 2012
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    muskymania Junior Member

    Paddling is great for going downstream but doesn't work to well going upstream in class II-III rapids. The whole idea behind this build is to allow me to go out by myself motor upstream and float back down. this eliminates the need for trying to have someone pick you up down stream and driving you back to your vehicle.
     
  8. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    My system for that was to carry a pair of rollerblades and skate back to the car and collect the canoe. This was when rollerblades first came out and I had a couple of near "deliverance" incidents with people who had never seen them before. Picture a guy in bike tights and pads with a headlamp on rollerblades in western VA in the 80's trying to skate 50 miles back to the car at night.:D

    So yeah, I understand your motivation. but a regular canoe isn't the thing. A jonboat would be better. Something with hard chines and a transom.
     
  9. Submarine Tom

    Submarine Tom Previous Member

    NOW I see what you're trying to do.

    Are your prevailing winds such that a kite off the bow could help you out?
     
  10. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    Be careful with what you develop. There is a patent out on a jet powered kayak, which may also involve canoes. You could be infringing on an existing patent if you proceed without proper authorization. I was the expert for Mokai Manufacturing when they got sued by the patent holder for potential infringement on their patent for Mokai's jet powered boat. We won the case, and won again on appeal because the Mokai boat is definitely not a kayak. However, a canoe is closer to a kayak than what we were dealing with. The owner of the patent may be watching the market for other potential infringements. If you are building just a one off for yourself, you don't have anything to worry about. But if you try to sell more than one, then you should be sure you have proper clearance or are doing something that does not infringe on any other patents. You can see the Mokai story on my website here: http://www.sponbergyachtdesign.com/Forensic.htm#Mokai.

    Mokai builds their hulls using rotomolded polyethylene, I believe. Their jet pump is custom made for them and is driven by a little Honda gasoline engine.

    Eric
     
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  11. muskymania
    Joined: Nov 2012
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    Location: TN

    muskymania Junior Member

    To the guy talking about the mokai patent, Im not trying to sell the canoe I make I just want it for my own personal use. The mokai is part of what gave me this idea. I've heard thats a $300 kayak with a $700 motor retailing for $3500. I do appreciate all of the suggestions but Im pretty set on what I need to do. I have never seen a gas powered engine on this river (not even a jet because of how narrow some areas are), its basically considered a kayak and canoe river. I have been fishing small stretches of it from a jon boat but it would be impossible to take it through much of the river. Access is pretty limited since alot of it is private property and there are no roads. Hence the whole canoe idea. I realize this is not the "perfect" craft but I think it would greatly increase my range and I could drag it over particularly rough areas.
     
  12. Eric Sponberg
    Joined: Dec 2001
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    Eric Sponberg Senior Member

    Roger that on going one off. The next question you asked was about the transom. If you build from an existing canoe, I think just cutting off one end and replacing it with a wood-epoxy plywood transom would do the trick. You'd probably want a glued and fastened joint, and if the canoe material is plastic, and epoxy doesn't stick, then Plexus would likely do it for the glue. If the canoe is aluminum, go epoxy all the way. You can also try 3M-5200 adhesive caulking--that sticks to just about everything. Fasteners would be countersunk stainless steel through the hull and into the edge of the transom. For the width of the transom, you would need only about an inch or two wider than the jet pump nozzle, probably.

    I hope that helps.

    Eric
     
  13. muskymania
    Joined: Nov 2012
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    Location: TN

    muskymania Junior Member

    From what Ive read the multi layered poly canoes would be toughest at holding up against rocks. My main concern is dealing with sealing up the hull if its multi layered so that it can handle abuse.(I know this is different but my current jon boat which is alluminum I have run marine tex up and down the seams and much of it has cracked just from walking around in the boat) Have you ever seen someone chop the back off of a canoe? I was thinking the same as you that the transom would only have to be slightly larger than the jet nozzel. Also Eric you said that you worked for mokai? from the pictures I saw it looked like the nozzel was actually above the waterline, wouldnt that significantly reduce power?
     
  14. Submarine Tom

    Submarine Tom Previous Member

    Hoyt,

    That is hilarious video.

    Looks like reverse pitch may be an asset!
     

  15. Eric Sponberg
    Joined: Dec 2001
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    Location: On board Corroboree

    Eric Sponberg Senior Member

    Square ended canoes have been around as long as there have been outboard motors.

    I was the expert witness for Mokai defending them in the patent lawsuit. The entire lawsuit hinged on what the definition of a kayak was, and so I had to define it for the federal court. The Mokai is not a kayak. They loaned me one of their boats to try out, so I got to ride around in it for a bit. The motor and jet are both modular--they clip into place in the boat. The intake is below the waterline, obviously, and it does not make any difference where the jet nozzle is, really, as long as it's shooting out the back. Of course, the jet pump is designed as a single unit with intake, impeller, and nozzle properly set up. When under way, virtually all jet boats have the nozzle outlet above the waterline at the transom, and the inlet is always below the waterline.

    Eric
     
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