Pedal Powered Boats

[Tiny Turnip]

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

[Tiny Turnip]

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.

[beppe]

Originally Posted by Tiny Turnip

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

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

[I57]

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

[beppe]

Originally Posted by Rick Willoughby

Thought it would be a good idea to start a thread on pedal powered boats. Aim is to cover design, development and operation of pedal powered boats...

Rick W.

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/archite...ral-discussion

including Rick's opinion to start up the discussion.

Thank you
Beppe

[beppe]

Originally Posted by I57

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

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/archite...ike-drive-unit

Beppe

[Tiny Turnip]

Maybe we need a open source or a free cad software.

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.

[Tiny Turnip]

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.

[I57]

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

[beppe]

Originally Posted by I57

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

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

[I57]

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

[Guest625101138]

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

[Guest625101138]

Here is a nice pedal propulsion system.

Rick W.

[tinhorn]

Originally Posted by Rick Willoughby

Here is a nice pedal propulsion system.

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

[Guest625101138]

Originally Posted by tinhorn

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

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