Building an Aluma-Jet

Discussion in 'Metal Boat Building' started by PSG-1, Oct 1, 2004.

  1. cyclops
    Joined: Feb 2005
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    Location: usa

    cyclops Senior Member

    Thanks PSG-1. Everybody please remember. Reefs and rock shoals are death to all types of prop drives lower than the hull bottom. Sand and mud or muck bottoms will destroy all COMMON built jet drives and possibly you if you eject in a turn with a channel marker pole in front of you. Very shallow running is definately asking for it to happen. Go slow in shallow.
     
  2. cyclops
    Joined: Feb 2005
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    Location: usa

    cyclops Senior Member

    PSG-1. Chain couplings can run that fast. They are used in racing Hydros. A mini scatter shield is a very good idea for the rare times they let go completly because no one saw the first of the 3 links opening.
     
  3. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Sounds like you are doing well and I am looking forward to new pictures.have a look at new image in photo gallery,Aircraft Technology it may give you some ideas.
     
  4. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Awful things happen with jet units too running in shallows.a blown jet.
     

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  5. Pdouda
    Joined: Mar 2005
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    Location: SC

    Pdouda New Member

    Your boat is looking good. Mine is still in it's infancy. I just made the cut for the bottom intake. I am planing on using the fiberglass shell from the waverunner. I am currently refiberglassing the intake to make it square and flat. I am planning on welding in 1-1/2" aluminum angle around the cut out. Then epoxying the fiberglass intake onto the angle. With a good amount of bolts as well. Hopefully it will work. I was going to use foam tape to seal it off, but I think the epoxy will do better. I am going to use 3M DP-190. It says it is flexible, hopefully it will be able to handle the different expansions of the materials. Anyone have any thoughts on this?

    I will need to post or email some pics.

    I finally got my boat registered. Turns out it is a 1950 jon boat. Pretty old...
     
  6. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Building an Alumna-jet

    A drive as in the image is great for shallow water,but with a smaller and more protection around the prop.In a flat bottom or pod or tunnel gives good steering and directional control.The outboard motor can be fitted on a swiveling mounting,air strut or spring loaded that lifts the motor straight up and down when going into shallows.The thrust of the propeller keeps the outboard against the back of the boat until the loss of thrust allows the outboard to swing back and up,and you can use an inboard/outboard the same way..the next best thing for shallow operation is a cushion craft or air boat,but they have drawbacks.Diagram is an indication only.
     

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  7. astro150
    Joined: Aug 2007
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    Location: south carolina

    astro150 New Member

    building an aluma jet

    after 2 years i finally finished my jet boat project. you can call it a vacume if you want . i challenge anyone to follow me with an outboard prop job. i can get on top in 6'' of water an run in 1.5-2''of water and it handles like a dream.
     

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  8. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Looks like a great job to me,and nice to see a finished project on this web site.It looks like you are in for some fun.Congratulations....
     
  9. astro150
    Joined: Aug 2007
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    Location: south carolina

    astro150 New Member

    building an aluma jet

    thanks tom.not meaning to brag but the boat has exceeded all my expectations. the river i built the boat to run in is all but dried up an i can navigate it without any problem.the stick steering works great along with a trigger style throttle.
     
  10. PSG-1
    Joined: Oct 2004
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    Location: XX' 5313 N, XX' 0526 W

    PSG-1 Junior Member

    Been a while since I've been here.....

    Man, I forgot all about this forum!!

    Astro150....awesome boat!


    Well, as far as mine, I started on it in February of 2005, and by July of '05, it was on the water an operational.

    It certainly had some quirks, which took some ironing out.

    As far as my driveshaft coupler, my original design was that I cut 4 flats on the end of the shaft, which was .700" in diameter, each cut being .100" deep, which made the end of the shaft exactly .500", with square ends. To this, I used a 1/2" socket, welded to a drive coupler that threaded to the back of the PTO coupler of the engine.

    Unfortunately, this was metal-to-metal wear, and the flats of the shaft would wear out after about 100 hours, on average. After having that fail twice, I went with a spartan jaw coupler, the one used on the Kawasaki 750 jet skis. It consists of two pieces of aluminum disks with "jaws" in between these 2 disks goes a rubber "spider" This design allows for misalignment, deflection, and vibration, reduces the metal-to-metal wear, and has so far proven itself to be reliable after about 200 hours of operation.

    In total, I probably have somewhere between 500-600 hours on my boat, since building it.



    Anyhow, here is a demonstration of what my boat can do:


    http://www.youtube.com/watch?v=Oo7C6NH4NGQ

    Some of these areas are just a few inches deep....
     
  11. PSG-1
    Joined: Oct 2004
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    Location: XX' 5313 N, XX' 0526 W

    PSG-1 Junior Member

    As for my throttle controls....

    I noticed astro150 used a trigger type control.

    I went with a "control box", which is basically just a big U-shaped piece of aluminum, with a big through bolt that goes through its center, as a pivot point for the control handles for reverse gate, and throttle. I used jam nuts and washers to control the amount of friction required to operate the levers.

    The levers themselves were originally made out of aluminum flat bar, with the ends radiused. But a few years ago, I made a set out of bronze, as an added touch.

    The way I did my throttle cable was to buy the cable conduit like that used on motorcycle control cables. Then, I bought some 1/16" stainless multi-strand wire (500 lb break strength) from McMaster Carr. Then, I took some small brass round rod, drilled and tapped it for setscrews, and then a cross drill for the cable to fit through. Basically, a small barrel nut end for the cable.

    I also had to make my own cable brackets, for holding the throttle, steering, and reverse cables securely. As well as designing a weedless grate system, using some stainless flat bar, and another push-pull teleflex cable, with a specially designed watertight housing where the cable goes into the intake scoop. By shutting off the engine, then, pushing down on a handle lever, I can drop the intake grate, allowing it to clear off any weeds. I used the existing design of the Sea Doo Jet Boat's weedless system as a model for my design.


    Here's a few pics:

    http://s142.photobucket.com/albums/r102/PSG-1/




    Anyhow, e-mail me at PSG1Shooter@REMOVETHISgmail.com if you are interested in pictures, details, etc.


    One other neat thing about my boat.......you will soon see it on national TV, on a show called "Only In America" with Larry the Cable Guy. In that episode, we took him out in Murrells Inlet, SC, oyster harvesting. Although they are still in the process of editing the footage right now, I'm fairly certain this boat will be seen on TV, as it was hauling members of the camera crew.
     

  12. sm465np205
    Joined: May 2019
    Posts: 11
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    Location: Michigan

    sm465np205 Junior Member

    I know this thread is old but for people scouring the web looking for info on jet conversions it's staggering the misinformation that's tossed around. Suggesting jets are just "vacuums" and cant be run in the shallows is completely ridiculous. Running shallow water is what the jet drive was originally invented to do. I've run my Berkeley jet thru mud, sand and everything else for years now and it still performs like new. If I come up on a weed bed I peg the throttle and coast right over without so much as clogging the grate. The only time the grate will clog with weeds is at low speeds or idling. Every forum I stumble on in which someone is inquiring about converting to or purchasing a jet, he is promptly barraged with BS from the crowd who thinks outboards are always the solution when they are clearly not. Stop spreading misinformation of you have no clue what you're talking about
     
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