Propellor for pedal powered catamaran

Discussion in 'Props' started by Tiny Turnip, Mar 31, 2008.

  1. Submarine Tom

    Submarine Tom Previous Member

    That's okay, but good to know.

    You may want to bump the RPM up then.

    800 - 1000 even.

    Nice you have some gearing to adjust with.

    The younger ones will likely have an "easier" ratio than the bigger "kids" :)

    You may want to look at the flex shaft in the pedal powered boats thread.

    A 3/8" (9.5mm) spring steel would probably do it, and you don't need a strut!!

    Hard to believe but it is self locating and easily retrievable in shallow water.

    A straight shaft would work too but you'd have to make the gearbox pivot in order to retrieve/raise the prop.

    Remember, pictures.
  2. Submarine Tom

    Submarine Tom Previous Member


    How'd it go Sunday?

    Are the tandems identical or at least with the same gearing?
  3. Submarine Tom

    Submarine Tom Previous Member

    Hello Darren...
  4. Submarine Tom

    Submarine Tom Previous Member

    Just got a PM from Darren:

    They won the race.

    He may post some pictures soon.
  5. onetonpump
    Joined: Mar 2013
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    Location: Sydney.Australia

    onetonpump New Member


    Angle-grinder gearboxes are 'the secret'::rugged & cheap [free] with a cluster of sprokets & a big chain-wheel, driven by two out-of-phase chain-linked pedal-sets. Trunnion mounted to raise//lower the prop=shaft.You can change ratios to suit the prop/pitch or headwind. I've been working on HUMAN-POWERED PUMPS for a long time as is revealed on>forums~~>water~~> challenge~ONETONPUMP the principles are the same [in Australia]
  6. Submarine Tom

    Submarine Tom Previous Member


    Welcome to the forum.

    You are not at all clear.

    Do you have pictures?

    Model numbers?

    Part numbers?


  7. onetonpump
    Joined: Mar 2013
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    Location: Sydney.Australia

    onetonpump New Member


    Hi Tom et Al, glad to be aboard,this is my topic//interest,been doing it for longtime. has pictures & a bit, has a long 'bloggy-waffle' & explains some details,even a bit on Blogspot as onetonpump.
    I'm a sailor, since a child,now ticketed MM,work on boats in many ways.
    Passionate about water,from surfing to pumping & particularly the interaction between human power & pushing liquid up & overboard from flooded vessels~ie. making a BETTER BILGE-PUMP which I have done to proof-of-concept prototype stage.
    It works better than I had hoped.
    The essence is spinning a prop//impeller::how I have done this is obscurely described in the above & I'' try to be clear.
    Most anglegrinders have a ratio 3 or more to one,usually the rotor is burned out;cut it to get about 5cm of shaft;spiral cut the windings with a hacksaw & reveal the shaft,make a sleeve coupling to the pumpshaft//propshaft,average shaft is about 1cm diameter.I use 1.2cm pumpshaft.
    Where the grinder disc was make an adaptor to take a cluster of sprokets from a bike [preferably a 5 sproket cluster to limit the overhang & in my case to fit within the 1.5 decimeter [dm][[let's talk metric please]] trunnion mount [a fork with holes aligned with the horizontal/input shaft] I use 14-18 tooth sprokets which allows for 5 speeds:: this is driven by a 100 tooth chainwheel,bolted to a bike axle//pedals,which in turn is connected by bike=chain to another pedals 90* out-of-phase.
    This is the 2-man pedal "PELOTON MODEL" I also have one man hand-crank using tooth belt drive. I'm looking for a new workspace just now ~ previous lease expired.
    The video is in the can.
    100/14 X 3.3 =23.5 is the ratio for max output RPM,I use a slightly lower ratio #15 or#16 sproket & it runs well [an old run-in set of gears is better than new.]
    With a pump this allows for torque/speed variations with different head//flow.
    I currently have two impellers high & low pitch.
    You can adapt this layout to a prop in your cat;ideally with a variable pitch prop.
  8. Submarine Tom

    Submarine Tom Previous Member

    What video?

    Ya, words are confusing to me.

    Can you provide links as I didn't see much of what your talking about.

    Perhaps you want to get that organized and start a new thread.
  9. onetonpump
    Joined: Mar 2013
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    Location: Sydney.Australia

    onetonpump New Member

    Yes confusion reigns;I will keep trying to clarify. for pictures, which also will confuse most,but the essence is I have made an effective,functional "HUMAN POWERED WATER LIFTING DEVICE" [UN terminology] the mechanism spins a prop, which is this thread.
    International Human Powered Vehicle Association.Org[onetonpump] has an equally confusing 'chatter',which has enough info for some elucidation.In this I've explained what I'm doing & where I'm coming from ~which is a sinking boat & a lifelong ambition to make a muscle driven low-lift water pump,specifically for removing bilge water & also the myriad uses for a machine like this,which can lift a ton a minute up a meter for one=man-input or two meter lift with two men of average fitness.
    The video is on disc,but I'm not satisfied with it so soon I'll remake it better,that's the plan,however with a bit of editing I may post on u-tube or here.That will dispell some confusion.Meantime look at the website
    Let me know if this makes sense.

    Attached Files:

  10. Islandur
    Joined: Jul 2015
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    Location: Norway

    Islandur New Member

    dazza73, sorry to bring this thread up after many years. But I am modifying a rowing boat to make it pedalable and would be interested in seeing pictures of your connection between the pedals and the propeller.

    All the best!
  11. onetonpump
    Joined: Mar 2013
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    Location: Sydney.Australia

    onetonpump New Member

    Pedal-Pusher= = =

    The clue is to have the pedals sliding along the sole [floor], rotating like a bike puts the pusher too high,even the reciprocation rockers like the Hobie levers arn't right.
    Keep on guessing?

  12. jit89
    Joined: Jun 2019
    Posts: 1
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    Location: India

    jit89 New Member

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