Split Paddle Wheel propulsion design

Discussion in 'Boat Design' started by Kermath, Dec 27, 2024.

  1. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    Hey, welcome back Kermy!
    How's the "as visually and mechanically complex as possible" design going?
    Any updates?
     
  2. Kermath
    Joined: Dec 2024
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    Kermath Junior Member

    I hadn't checked on this thread for awhile and was surprised to see that it is still going. I am all for a good spirited debate/discussion especially over facts that can be quantified. So you guys carry on and have fun. I have attached a video of the Taylor Falls Paddle Boat. I don't know how to edit it down but if you make it a few seconds in, you get to see a split wheel paddle boat spinning in place. So to answer my question, it is worth it, in my opinion, for me. Efficiency and economy do not enter into the picture. Kind of like the solution to the 80's movie War Games. The only way to win is to not play the game. So the most economical way to attack this project is to not do it. Boats cost money. Just a matter of how much. I don't need a boat. So back to my internal struggle. I do like making stuff and the boat fills the bill, currently. Where am I at currently? Mechanically I have it figured out. Either 2 gas engines that are old or look old and are dependable with transmissions and gear reducers to get the rpms that I need. I am not looking to knit pick the details at this point. 2 engines gives me total independent control over each wheel in the rear. Keeping the engines at the same rpm and steering with the rudder is pretty much the same as not having a split rear wheel at all. I would only use them independently for close quarters maneuvering which is ok but a cheap and dirty bow thruster could just about accomplish the same thing. In that video you can see that the Princess uses differential wheel speed for steering while cruising down the river. Going that route would maximize the use of the whole effort of the twin wheels. The problem is my desire to use old mechanical equipment. Throttling an engine down to turn the boat a little wouldn't be a problem but going to neutral and then reverse while under way could keep a person busy. In the best scenario all of the controls would be in one location. I picture the helmsman acting like the Wizard in the Wizard of Oz when the wiz was behind the curtain trying to turn all the valves and pull levers at the same time to impress his visitors. Not quite the scenario I would shoot for. Oh, and have an engine stall out in the middle of that.
    My other personal favorite is electric. Easy to control. Quiet. Basically no lag in control. Have 2 motors turning cranks or wheels with long arms that connect to the paddlewheels. I would still get some of that old timey look.
    So with either scenario I get a functional boat. And as with most of my projects the question of "So now what?" comes up. On some of my projects I can make it through the whole cycle of conception, research, construction, use, loss of enthusiasm and dissolution without having to actually take on the project.
    So I'll just let paddle wheel project sit for now.
    However, I have kicked around another source of propulsion for years. I came across it when I was researching paddle boats. It had to do with the earliest application of the steam engine to propelling a boat. One concept had the engine and a lot of linkages hooked up to oars. Not real practical. The other one that is probably the easiest most straight forward use for the engine was having it drive a water pump and shooting the water out the rear of the boat. An early jet boat. I kind of ran with that concept for awhile. I designed a pump with 5 vertical cylinders all actuated sequentially with a revolving disk of some type from above. It sucked water in through the base and shot it out the side. I got pretty far but my lathe started giving me problems and other stuff came up. I may have to revisit this. I attached some pics of how far I got.
     

    Attached Files:

  3. clmanges
    Joined: Jul 2008
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    clmanges Senior Member

    Why not run it with a single engine through a hydraulic drive? I'm betting that's how they drive the Princess. You could set it up with a joystick controller like the way they run Bobcat loaders.
     
  4. rangebowdrie
    Joined: Nov 2009
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    rangebowdrie Senior Member

    A few years ago, we had a paddle excursion boat with hydraulic drive operating near where I live, when it came by the noise was deafening, the hydraulic noise drowned out the engines driving the pumps.
    If you want to use a hydraulic motor to drive the wheel direct without a reduction gear, you need a large displacement motor to generate the needed torque at only 40>50rpm or so.
    When you add up the pump, motors, coolers, valves, controllers, reserve tank, and miles of high-pressure hose, (all of which are constantly seeking to leak,) you've got an expensive system, (plus the earplugs you need).
    It's not a peaceful way to power a boat.
     
  5. fredrosse
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    fredrosse USACE Steam

    "...One concept had the engine and a lot of linkages hooked up to oars. Not real practical. The other one that is probably the easiest most straight forward use for the engine was having it drive a water pump and shooting the water out the rear of the boat. An early jet boat. I kind of ran with that concept for awhile...."

    That is exactly what went on in the 1790s, with the John Fitch paddle mechanism vs the Rumsey pump method. The Fitch paddle mechanism is actually far more efficient than the water pump method. If you want some history, look up any of several John Fitch articles. Interesting that John Fitch ran his steamer in ordinary commercial service for thousands of miles in 1790, fully 17 years before Fulton got fame and fortune with his wildly successful steamer on the Hudson river. FitchModelSternPaddles.jpg
     
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  6. rangebowdrie
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    rangebowdrie Senior Member

    Over 90 years in operation, can still earn her keep.
     
  7. montero
    Joined: Nov 2024
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    montero Senior Member

    Interesting piece of engineering :
     
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  8. Will Gilmore
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    Will Gilmore Senior Member

    [​IMG]
    Just like Mary Ann and Mike Mulligan.

    -Will
     
  9. Kermath
    Joined: Dec 2024
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    Kermath Junior Member

    I did do some research years ago about the battle that raged between Rumsey and Fitch. You mentioned "The Fitch paddle mechanism is actually far more efficient than the water pump method." I know Fitch did ok until the technology changed. Were you referring to Rumsey"s pump or any pump? Modern or old. I can see where that dog paddle arrangement would provide forward thrust. Apparently the best at the time but there are some inherent inefficiencies with that type of paddle arrangement.
     
  10. rangebowdrie
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    rangebowdrie Senior Member

    "Some" inefficiencies. :D
    Me thinks that "some" is being quite kind, but yeah, they did the best they could
    with what they had. ;)
     
  11. fredrosse
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    fredrosse USACE Steam

    The better efficiency for displacement boat speeds is fundamentally obtained by moving a large amount of water. Pumped propulsion in 1790 was pushing a small fraction of the water that was moved by the Fitch mechanism, so the Fitch mechanism had much better efficiency. This soon evolved into normal paddlewheel propulsion, which persisted for about 100 years, while normal propellers were several efficiency % points better than paddlewheels, and took over in popularity. Pumped propulsion for low speed boats is generally not practical, but it is OK for higher speed boats.

    Interesting that personal watercraft are all water jet propelled (for safety reasons), but stock snowmobiles (running on water) are actually faster, and the snowmobiles are all virtually the same as a paddlewheel as far as propulsion principles are concerned.
     
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  12. Will Gilmore
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    Will Gilmore Senior Member


    Do you think they could get up to speed with just the treds starting from a submerged and still state, having first to go through the high resistance, low grab state between standing still and planing?

    -Will
     
  13. fredrosse
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    fredrosse USACE Steam

    The fast snowmobiles get going on the solid, (or very shallow water, a few inches deep) then enter the deep water. They sink like a rock if they try running on water without high velocity. They certainly need the dynamic lift of the skis and propulsion belt moving over the water to avoid sinking.
     
  14. Will Gilmore
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    Will Gilmore Senior Member

    I was thinking, if they didn't sink, such as supported by some sort of flotation, pontoons, would the drive tracks be able to bring them up to planing speeds on the water alone?

    -Will
     

  15. fredrosse
    Joined: Jan 2005
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    fredrosse USACE Steam

    "I was thinking, if they didn't sink, such as supported by some sort of flotation, pontoons, would the drive tracks be able to bring them up to planing speeds on the water alone?"

    Yes, that would be entirely possible, but then the machine would be basically an oversize personal watercraft, with the relatively dangerous propulsion system that could injure people. Considering efficient propulsion, a conventional propeller would be best for personal watercraft, but all manufactures use water jet propulsion because it is much safer.
     
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