Modern paddlewheels

Discussion in 'Boat Design' started by Guest, Dec 23, 2003.

  1. tinhorn
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    tinhorn Senior Member

    Man, it doesn't get much simpler than that!
     
  2. Village_Idiot
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    Village_Idiot Senior Member

    Snowmobiles have been discussed a number of times in the past on this forum. However, they are not considered amphibious in the true sense because they typically do not float at zero speed. They require momentum and power to stay afloat.

    IMO, a true amphibious craft would be able to float well at zero speed as well as in choppy to rough waters.
     
  3. Manie B
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    Manie B Senior Member

    very nice pedal system, something new:)
     
  4. The Loftsman
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    The Loftsman The Loftsman

    Seem to remember that the Royal Navy was still using paddle powered tugs up to not so long ago, they were better than the screw driven ones at the time according to records.
     
  5. sharpii2
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    sharpii2 Senior Member

    How long ago was that? When my dad was a boy? When my grand dad was a boy? Or was it when my great great grand dad was a boy?

    It took some time to get propeller blade size and shape just right.

    Do you know why they are called 'screws'?

    Because the original propeller looked like a giant screw.

    On an early voyage, it hit something and broke in half. And the boat picked up speed!

    Some time in the mid to late 19th century (after 'screw' technology had morphed to propeller blade technology), a tug a war was arranged between two ships (presumably of equal size and HP). One was a side wheeler and the other had a propeller.

    Can you guess which one won?

    The loser was towed backwards at about 4 kts, IIRC.

    I suppose a side wheel tug would have greater turning torque, as the thrust is far off to the side. If you stopped one wheel and kept the other one going...
     
  6. mydauphin
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    mydauphin Senior Member

    I forget the name of the tugs that have the paddles sticking out the bottom, they are good for turning and providing thrust in every direction but not a true paddle boat. The only advantage I see to paddle boats is lowest draft possible in theory.
     
  7. The Loftsman
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    The Loftsman The Loftsman

    Hello there sharpii2,
    Having no idea how old you are and not interested neither, you may want to have a look at this side wheel paddle tug at the shipyards in Leith, Scotland just before the outbreak of the Second World War 1938, Follow the link to see,

    http://www.leithshipyards.com/ships...m-ferry-port-jackson-ferry-co-built-1938.html

    and the Royal dockyards in the U.K. still very successfully used them into the 1950 due to there mounoverability in harbours. Of course today’s Azimuth power systems are and should be better its been a long time since we moved on from wind power!
    And when you speak or at least i speak about ships I go back for as long as there have been boats or ships on the water, because as a member of the Shipwrights Guild we are perhaps the second oldest profession known to man I should not need to tell you what the oldest one is.
    I will always be here to try and help and to even learn but I don’t do smart assed comments very well.
    I happen to think that you will find that they were called screws after a certain Mr Achimedes and i quote- That began to change with the launch of the Archimedes in May of 1839. The ship was unique in an age of paddle-wheel steamers. The Archimedes was steam powered, but was not propelled by paddle-wheels. Instead, she was fitted with a device described to the patent office as "an improved propeller" in the shape of "a sort of screw, or worm."

    Cheers
     
  8. portacruise
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    portacruise Senior Member

    My:

    Not lowest draft anymore. There are hydrofoils, hovercraft, planing boats, surface piercing props, etc., at least for smaller boats.

    Porta


     
  9. upchurchmr
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    upchurchmr Senior Member

    Have you taken out a patent? I personally don't care about powered boats, but I had friends who built a bicycle powered paddlewheeled catamaran (inflatable hulls) in the early 80's. The way you angled your "paddles" should have helped them, although they were successful - 4 riders, 6' dia, 6' width wheel. 20' rooster tail accelerating.

    Do you have a video of this in the water?

    Marc

     
  10. PlaningWheel
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    PlaningWheel Junior Member

    I have applied for patents.
    I hope to put the powered model in the water within the next 4 weeks.
     
  11. upchurchmr
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    upchurchmr Senior Member

    Good to hear it. I'm not an expert, but if this is new I hope you get credit.
    Not sure there is any money in it, but.... Good Luck
     
  12. Village_Idiot
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    Village_Idiot Senior Member

    I don't think anyone is disputing that the typical propeller is more efficient than the typical paddlewheel. However, it would be interesting to see that test repeated with a modern feathered paddlewheel...

    I think the point was that paddlewheels still have their place and their uses. They excel at providing robust propulsion to larger vessels in shallow-draft applications. The better-built paddlewheelers have been known to 'walk' across shallow areas, where the paddlewheel becomes as much a terrestrial wheel as an aquatic propulsor. They are definitely much more efficient in terrestrial applications than a propeller. :D
     
  13. sharpii2
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    sharpii2 Senior Member

    Right on!

    I actually saw a picture of a river ferry, built in the 1990's that had a paddle wheel.

    Rocks are less likely to screw up paddle blades than propeller blades. because the paddle wheel has less draft and often turns slower. The river in question (I can't remember its name) was rocky and shallow.

    I doubt the articulated paddle wheel would have done much better against the deep propeller.
     
  14. tom kane
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    tom kane Senior Member

    I think many people don`t understand how a screw propeller really works. A propeller does not "screw" it`s way through the water but displaces accelerated water rearwards and gravity and the atmospheric pressure push the displaced water back into place ..or try to until the prop stops turning. And vacuums do not suck but atmospheric pressure rushes in to replace the displaced air.Paddle wheels work the same way by displacing water rearwards and do not work like a wheel unless on land.???
     

  15. Village_Idiot
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    Village_Idiot Senior Member

    I've often wondered about the propeller's propulsion methodology. I thought maybe it also had something to do with the low pressure created on the leading side of the blade, similar to lift created on an airplane wing. Also, would the same effects be created with an air propeller as with an aquatic propeller - i.e., is an airboat powered by rearward thrust, or low pressure ahead of the blade pulling the whole unit forward? Perhaps this deserves a new thread...
     
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