Pedal Powered Boats

Discussion in 'Boat Design' started by Guest625101138, Jul 14, 2008.

  1. Submarine Tom

    Submarine Tom Previous Member

    Wow Dave, I hadn't seen that one.

    It has gearing, 3 in the front hub, 7 in the rear.

    I don't care for the off-set.

    I'd have to butcher it to get to the shaft.

    I appreciate the lead but I can't say I'm too interested.

    Thanks Dave.
     
  2. MLampi
    Joined: Aug 2008
    Posts: 74
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Bellevue, WA

    MLampi Junior Member

    The gentleman's name is George Tatum, and the last I heard (about a year ago) he had a fair number of the Involute gearboxes sitting on a shelf and available for sale.

    Yes, the gearboxes are big and quite heavy, but they can also take the torque of a strong pedaler and, best of all, are trivial to mount and use.
     
  3. Submarine Tom

    Submarine Tom Previous Member

    Thanks, but they're 1 : 3.25

    I'm interested in 1:1 perhaps 1 : 1.5
     
  4. GMR
    Joined: Sep 2011
    Posts: 54
    Likes: 1, Points: 0, Legacy Rep: 22
    Location: Nova Scotia

    GMR Junior Member

    Tom
    My only experience with Mitrpak gearboxes involved a 2:1 ratio with two 1/2 inch shafts on the outside of the box. The stepped down shaft for the smaller gear failed during the testing of my cat under non racing loads. I sent it back and requested it be changed to 1:1 which they did cheerfully (but not instantly) and without charge. I ran out of season but will try it out on the water in the spring.
    Cheers, Glen
     
  5. MLampi
    Joined: Aug 2008
    Posts: 74
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Bellevue, WA

    MLampi Junior Member

    I've used Mitrpak 1:1 gearboxes with the 3/8 inch shaft in the Cadence pedal boat for years, with a 6:1 ratio 1/4 inch sprocket drive. It has proven to be very reliable even under racing loads, though it needs solid pins to secure the gears. The hollow roll pins prove to be inadequate over time. This is with over 40 Cadence pedal boats in use around the world.

    I have also used the Mitrpak 1:1 1/2 shaft gear box with a 5:1 ratio sprocket drive. It has also proven itself to be reliable under racing conditions, though it has not undergone the same length of testing. This is also with solid pins rather than roll pins.

    Michael Lampi
     
  6. GMR
    Joined: Sep 2011
    Posts: 54
    Likes: 1, Points: 0, Legacy Rep: 22
    Location: Nova Scotia

    GMR Junior Member

    That's good news Michael...my overall drive ratio was about 7:1 which was a bit unrealistic anyway.
    Glen
     
  7. Submarine Tom

    Submarine Tom Previous Member

    Thanks for that guys.

    Mitrpak also makes a 5/8" shaft model with double the strength rating of the 1/2".

    33% heavier (4 pounds) and $40 more.

    Slightly larger dimensions.

    Did someone mention they ordered one pedal crank spline ready?

    It would be nice to get a longer splined output shaft as well to make for leg length adjustability.
     
  8. Submarine Tom

    Submarine Tom Previous Member

    OMG!

    My prop estimates were seriously flawed.

    What on earth made me think turning a two foot prop at 80 RPM was going to get me anywhere?

    At least my hydrofoil estimates were close...
     
  9. Submarine Tom

    Submarine Tom Previous Member

    Jeremy,

    It's been a week of number crunching and it doesn't look good.

    I think you were right that the wetted area of a pod may cancel the buoyancy benefit.

    A variably inflatable pod may work but the numbers are so close I'd have to try it to find out.

    The air prop also becomes very attractive on paper but talk about a fair weather sailer...

    I do think the pod idea for the power drill competition is promising however.

    How is your build coming?

    Cheers!
     
  10. Submarine Tom

    Submarine Tom Previous Member

  11. El_Guero

    El_Guero Previous Member

    One is shimano 7 speed and the other shimano 8 speed.

    too bad that doesn't look like it would fit on my trike ....

    :mad:
     
  12. El_Guero

    El_Guero Previous Member

  13. El_Guero

    El_Guero Previous Member

  14. Coach Dave
    Joined: Jun 2011
    Posts: 70
    Likes: 4, Points: 0, Legacy Rep: 40
    Location: Malabar, FL

    Coach Dave Junior Member

    You can see my other pedal powered boats videos on youtube if you search on "runbikepaddledave" Enjoy! ;)
     

  15. Tom the rower
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Jacksonville, Fl

    Tom the rower Junior Member

    Coach Dave....I sure wish there were more of your videos on youtube. I really wish you would take us on a tour of your boat. Particularly, I would like you to discuss the design choices on the hull shape and length, and how you connected and made your amas, and finally a discussion of your pedal set up, including gearbox, prop info, especially for a boat so long. Really nice that you can carry so much people and gear. Impressive.
     
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