Pedal Powered Boats

Nothing really to do with boats but a lot to do with pedal power.

My friend Peter Heal has taken the long way around to make a dinner engagement in Sydney on Saturday night 13th June.

If he makes it he will have covered 15,087km under his own power alone without support in under 50 days. He is proof that you are only as old as you choose to be.

 

It amazes me how people can do these endurance events. I have done a few single day canoe and bike events but if I had to repeat it the next day and the next etc. etc. That would be something else again, mentally as well as physically. Well done Peter, looks a fast bike from the pic.

Ian

 

Endurance, is all mental ...
just turn on that little switch in your head and go!
sure, the motor gets tired, just like any,
but just give it a bit of a pit stop and be on your way again.

The link below is to my 400 mile coastal texas,
border to border, Unlitter kayak Tour
done (with bus ride home) in 20 days.
http://www.spotadventures.com/trip/view?trip_id=202373!)

 

Ian
He finished last night. He cut 49 hours off the previous record and travelled further. Allowing for the further distance it is about 69 hours better.

Pete struggled to retain weight but as you get lighter the hills get easier. I expect after almost 49 days he was fitter than when he started if he is not too wasted.

 

Prop direction of rotation

Rick

My new boat with the outriggers & curved flexable drive, swings to my left when under power. The drive shaft is positioned on my right & the prop rotates anti-clockwise if viewed from the rear.
Have I made a mistake on the direction of rotation & will the problem be cured if I change the rotation and prop to clockwise.

I have now replaced the strutt bearing to ball races and outriggers have been raised up by 55 mm.

Dennis

 

Rick has left the list. See post #49 for info on how to contact him:

http://www.boatdesign.net/forums/boat-design/ideas-fast-efficient-electric-hull-33336-4.html

 

What about a hydraulic drive?

Hi all, firstly I must say that I have immensely enjoyed readeing through this thread, very interesting. I guage that on the whole, people are wanting to build these boats for speed and efficiency.
I am considering building a drive for my fishing kayak and have been trying to come up with a farly robust and cheap way to propel it with peddles. I have 2 main ideas that I would like to put to the forum in case other people have thought of or even seen them implimented elsewhere.

The first idea is to use 2 small power steering pumps, connected by hydraulic line. The first would be driven by pedal the second would be driven by the hydraulic pressure as a motor, and would be driving a prop. I know that this may be a bit heavy but im would give me flexibility to mount the prop at the back of the boat in an outboard motor type arrangement without having a drive shaft over the side of the boat ready to tangle the fish.

The second idea is to mount a fin on the back of the boat, something like a dolfin fluke. It would be driven by cables from 2 linearly (forward and aft) moving pedals. I have seen the tailboat ideas but it seemed to make much disruption to the water, plus having the tail move up and down would allow me into quite shallow water by reducing the stroke. I thought this idea may work as the lunocet fin seems to be very successfull. However, does anyone know how badly this idea would make the nose of my kayak pitch up and down? I could see that perhaps i could get into a situation of building amplitude where the nose might bury itself...

Any comments, links to similar ideas would be greatly appreciated.

 

It seems the pedal boat threads here go on for many pages, but if you do a search, and manage to read them all, I bet you find that someone a lot smarter than me has stated that the power loss in a hydraulic drive is so extreme as to make hydraulics a poor choice. It sure would simplify things, though, if such a system was workable!

If you're looking for a cheap drive system, Google "twisted chain drive". Looks interesting, but I've read of a few people disappointed with twisted chain. I don't know how closely they followed the suggested design.

 

While I understand why you are saying this, I do not agree.

If one is not physically fit enough to get them into the game in the first place, no amount of mental anything is going to get you to the finish line. If this weren't so, then there'd be no expression, "Hitting the Wall, or He Bonked Four Miles Before the Line".

It's a complex game, this endurance thing. There have been thousands of really smart people working on the issues for a very long time and they still don't have a comfy formula that works for every circumstance.

 

That's the beauty of science and engineering. Anyone, anytime can challenge established basic laws which come into play. If they find a circumstance where it doesn't work, the law must change or a corollary must be added. Go for it, I would love to see some new discoveries!

Porta

 

"What about a hydraulic drive?"

I was trying to find some numbers to give here but Tinhorn said it well anyway, hydraulics do have many uses but not on a HPB. Way too power wasteful. An alternative might be a leg powered DC generator driving a motor, but these are still not that good, except for the flexibility of such a system. If you want to try one of these an inexpensive way to start is to find a DC treadmill motor to use as the generator. Because their nominal voltage is usually 90 to 120 volts they do not need to be geared up as much as lower voltage motors/generaors do and they can convert much more power than a human can sustain to put out for long.

 

As has already been mentioned, the losses in a hydraulic transmission will be massive and probably leave you with little, if any, useful propulsive power.

An electric system can work, but again will be pretty inefficient. As a rule of thumb, work on the basis that both the generator/alternator and the motor will be around 80% efficient. If your pedal input power is 100 watts (a reasonable figure) then you'll get 80 watts out of the generator and about 64 watts out of the motor into the propeller.

The propeller (if it's a large diameter, slow turning, narrow blade chord design) might be around 80% efficient, so the actual propulsive power into the water will be around 51 watts. In other words, this system will waste about half of the power that you put into it.

A direct drive system, either using a gearbox and flex shaft as Rick has done, or using an enclosed chain drive, might have mechanical losses that are only around 5%, perhaps less. Overall I think it's possible to get a total system efficiency of maybe 75% or perhaps a little more using direct mechanical drive, a lot better than the ~51% from a good electrical drive.

Jeremy

 

electric drive references- was hydraulic

See post #364 and surrounding on this list for reference paper on direct e-drive and comments on efficiency:

http://www.boatdesign.net/forums/boat-design/pedal-powered-boats-23345-25.html

Oops, the message below was meant for comment on hydraulic, was paired with wrong quote:

 

anyone ever saw hand drive unit.

i got this today.



mmm not sher how efficient it is good it for the fun off it..must be hard and very tiring o turen that handle by hand but got ideals.

 

ok there you go guys,

right now i am a yaker and got a few yaks around here but i have been looking at 2 deferent kayaks..the hobies and the natives the hobie push style pedlas and the natives pedla style..the push style is easyer to do i been trying boths.

native pedal style and a prop.
http://www.nativewatercraft.com/ult_14_propel.cfm

hobi style a push style flip flop fins
http://www.hobiecat.com/fishing/models_proangler.html

i would love to build my own pedal drive but a push style like the hobie but insted the push style would turn a prop inted off the flip flop like it as now.

any pict off people doing something like that a push style that turn a prop..?

thanks.

joco