Pedal Powered Boats

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

  1. Tiny Turnip
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    Tiny Turnip Senior Member

    file types, dimensions...

    Beppe, it always used to be possible to export .dwg drawings from Autocad as a .jpg, which would then be universally viewable. I can't remember whether this is through the 'export' dialogue, (on the file menu) or as a screen dump, and its 12 years since I used Autocad in anger, so I'm pretty rusty! I'm sure it is much more user friendly now.
    BTW, in your dimension notation, 12' would denote 12 feet as an imperial measurement: 12 inches would be 12".

    Adrian
     
  2. Tiny Turnip
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    Tiny Turnip Senior Member

    A slightly different take

    This is the Winsome, a production pedal launch, from Swallow boats

    Length: 5.3m (17ft 6ins), Beam: 1.1m (3 ft 7ins), Weight (fully laden): 72kg (160 lbs), Weight (stripped for transport): 55 kg (120 lbs), Maximum speed: 7mph, Cruising speed: 4mph.
     

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    Last edited: Jul 31, 2008
  3. beppe
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    beppe Junior Member

    Open Waterbike mistakes & drive unit interface

    Thank you Adrian! Gross mistake, I'm ashamed. I just corrected it...
    Thank you also for the conversion tips. I actually tried a converter downloaded from the web with bad results, my oldish version of autocad doesn't export to jpg, but the screen dump (from the Operating System) gives an acceptable jpg. I didn't think of it. Ashamed again ;-) I post the Open Waterbike proposal for the connection of a drive unit to a forward tube for Ian and other interested colleagues.
    This solves half of my sharing problem, the other half being the possibility of modifying the drawing and giving it back to the community. Maybe we need a open source or a free cad software. Is there any commonly used among the members of this forum?
    Beppe
     

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  4. I57
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    I57 Senior Member

    Autocad

    Beppe

    I have Autocad LT but it is a 1997 version which is why it couldn't read yours.
    I do a screen dump and send pic as a .jpg file as this way everyone can see the drawing. There are so many CAD programs and people tend to use the ones they are used to that it opens up another can of worms ( a bit like the open waterbike project ). Until you need working drawings .jpg files are ok.

    Ian Cassell
     
  5. beppe
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    beppe Junior Member

    monohull or multihull? the Open Pedal Powered Boat dilemma

    The monohull/multihull dilemma, as pointed out by Rick in another post, is possibly the most important architectural choice in designin a Pedal Powered Boat.
    It is even more important for an Open Pedal Powered Boat, since it is is an architectural choice that involves modularity and reusability of components.

    Could you please give your opinion on this issue, colleagues?

    I set up the problem at

    http://www.openwaterbike.com/architecture/the-open-waterbike-architecture/architectural-discussion

    including Rick's opinion to start up the discussion.

    Thank you
    Beppe
     
  6. beppe
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    beppe Junior Member

    Open Pedal Powered Boat drive unit mounting

    Hi Ian
    I enclose a 1997 Autocad LT version of the file, I hope you can open it.

    I would like to evaluate different kinds of drive unit mountings in order to assess how they can fit an Open Pedal Powered Boat. I'm trying to set up this at:

    http://www.openwaterbike.com/archit...ke-architecture/the-open-waterbike-drive-unit

    Beppe
     

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  7. Tiny Turnip
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    Tiny Turnip Senior Member

    Beppe, there is Sketchup, which is available free from Google

    http://sketchup.google.com/product/features.html

    It is a very easy to learn and use modeller, with lots of tricks up its sleeve, and can merrily skin 3d surfaces between profiles (it includes a terrain modeller which can generate from contours so should be able to handle hull shapes from lines.) It is fine for straightforward dimensioned 2d cad. It is not designed for naval architecture, and so won't generate any performance predictions - it is primarily aimed at architectural design. The free version will import .dxf, .dwg etc, but only export .jpg and a couple of others. There is no reason why users shouldn't modify and exchange drawings in the native sketchup format, however.
     
  8. Tiny Turnip
    Joined: Mar 2008
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    Tiny Turnip Senior Member

    Looking forward to this moment...

    As I am going away on holiday today, I thought I would temporarily leave you with an artist's impression of my boats first trial.
    Taken from 'How Tom beat Captain Najork and his hired sportsmen' by Russell Hoban, illustrated by Quentin Blake. As fine a book as you are likely to read.
     

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  9. I57
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    I57 Senior Member

    Autocad drawing

    Beppe
    Thanks for the drawing, I was able to open it in my version of Autocad.
    With the dimensions you show for example 175 (7), what does the number in the brackets mean?

    Ian Cassell
     
  10. beppe
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    Location: Udine, Italy

    beppe Junior Member

    Open Pedal Boat Drive Unit connection

    Hi Ian
    imeasures in this drawing are metric (millimeters, mm); the number in the brackets is the same measure in inches, crudely converted as 1 inch=25 mm.
    Beppe
     
  11. I57
    Joined: Feb 2008
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    Location: Melbourne, Australia

    I57 Senior Member

    Seat position

    Does anyone know the best position for the seat in relation to the pedals. Is there an optimum angle for the seat backrest, I have mine so that I can adjust it but am wondering if I am leaning too far back. With the seat height in relation to the axis of the pedal crank how low or high should this be. The open waterbike shows the bottom of the seat at the same level as the crank axis but a lot of boats have the seat much lower.

    Ian Cassell
     
  12. Guest625101138

    Guest625101138 Previous Member

    Ian
    There are studies around on this but I do not think it matters a lot. The lower you can get then there are advantages from stability and windage. If you have your heart placed lower than the top of the crank you will find you get numb feet. My understanding on this is that the blood drains out because your feet are not intended to be higher than the pump.

    Your body tend to adjust to the position the more you use that position. You train muscles to suit.

    The most efficient cadence is around 65rpm. Endurance cyclist work higher than this to avoid muscle tiredness. So there is a trade-off between biomechanical efficiency and muscle soreness.

    There is data that shows recumbent position has almost identical efficiency to upright position providing you are using cleats.

    Rick W
     
  13. Guest625101138

    Guest625101138 Previous Member

    Swing Arm & Outboard

    Here is a nice pedal propulsion system.

    Rick W.
     

    Attached Files:

  14. tinhorn
    Joined: Jan 2008
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    Location: Massachusetts South Shore.

    tinhorn Senior Member

    Looks clean, but I can't figure out the cable routing.
     

  15. Guest625101138

    Guest625101138 Previous Member

    I have attached a view of the test frame I built. It is reeved with green nylon cord so you can follow the path. This shows the 3" drums Warren had made up for me.

    There is also a video showing a test load being spun up. This was a little fan rotor geared up to give me some load. The chain and gearbox were done very quickly to get the load to something like I would have in a boat.

    Understanding the reeving is possibly the closest thing you could get to rocket science. This is one of those things that are hard to believe until you see it. The guts of it is two $12 roller clutches.

    Rick
     

    Attached Files:

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