Why Paddles Instead Of Propellers? (Human-Powered)

[Racerbvd]

Originally Posted by sc_rufctr

i want one!!!!!!!!!

[RWebb]

now... why do animals not use propellers

[Moses]

Originally Posted by RWebb

now... why do animals not use propellers

Rotifers do. Well... Sort of.

[RWebb]

I guess we better define propellers...

and also note that we are talking about the function being for propulsion, not filling your ... ah... pie hole.

[fuelie600]

I have a pair of Hobie Tandem kayaks with Mirage drives. They are a very efficient propulsion system. You can maintain a decent speed for long periods of time. They are great for fishing since your hands are free to manage your pole/line. It is easy to maintain 3 MPH to troll. With two people pedaling, we can easily maintain 4MPH.

Check the video:

[RKC]

Yes, and they have a trimaran/kayak/mirage drive boat too if you want to put it all away and catch some wind.

[doug_porsche]

Originally Posted by Flieger

You have it backwards. Horsepower defines the top speed. The gear ratio spread (which affects the thrust) and ultimately the amount of area under the power curve define how fast the car can reach top speed.

Yep, my bad

[RWebb]

how many hp can a human put out?

[gtc]

Originally Posted by sc_rufctr

Those are cool, but going up hills is always so difficult...

[porsche4life]

how many hp can a human put out?

Well, how big an ol boy are ya?

[sc_rufctr]

Originally Posted by RWebb

how many hp can a human put out?

A pro level cyclist hunched over at his prime puts out about .5 hp.

[jyl]

These guys used a pedal-powered, two-man boat to circumnavigate the world.

Expedition 360 - Pedal Boat Moksha

Maybe you could do it with paddles. I know a guy who paddled a kayak from California to Hawaii, and there have been a couple of Atlantic kayak crossings (though those were quite sail-dependent). But those were kayaks, a whole different level of risk/exposure than the craft these two guys used. Not that they had a pleasure cruise.

[fred cook]

The submarine used by the Confederates the "Hunley" used a handpowered crankshaft turned by 7 men for propulsion. They were able to make about 4-5 knots speed on top end. It was the first submersible to sink an enemy ship, in this case the USS Hustatonic, a blockade ship off Charleston harbor. Unfortunately for the 8 men on board the Hunley, it was a one way trip as it sunk for some currently unknown reason.

[svandamme]

Imho it's all about cost

A pedalo is the simplest an cheapest thing anybody can build with a FG hull and a minimum of engineering. Anything else will cost substantially more for little improvement.



Pedals already turn in the right direction paddles
so you can make do with one single crank shaft and direct attachment of the paddels.
and you can have it sit above the water line, so you have less trouble with seals.

for a prop you need to change the mechanical direction, you have to get a propshaft through the hull, have a good seal, more complex to get it to work, more things to go wrong , break, need maintenance = higher cost. And to what advantage? it'll just need more maintenance and it will hardly go faster.

[svandamme]

Originally Posted by sc_rufctr

A pro level cyclist hunched over at his prime puts out about .5 hp.

Most need Horse Medicine to get to that point.

[wagonicfolding]

They help a bit, but are hard to set up, and aren't good enough on their own. They're nice for boosting propellers, though. However, they need a bit of work to get working properly.

[RWebb]

Originally Posted by sc_rufctr

A pro level cyclist hunched over at his prime puts out about .5 hp.

a bit of a rhetorical question for me I guess

here is a wiki - note the duration issue

https://en.wikipedia.org/wiki/Horsepower#:~:text=When%20considering%20human%2Dpo wered%20equipment,a%20period%20of%20several%20hour s.

[gtc]

Thread appears to have been bumped by a bot.

FWIW, there are quite a few entries in the Race to Alaska (www.r2ak.com) that have some sort of pedal drive now.

[GH85Carrera]

Originally Posted by sc_rufctr

A pro level cyclist hunched over at his prime puts out about .5 hp.

Yea, but if he rids a horse and not a bike it is one HP!

[Tobra]

Originally Posted by HardDrive

Anything mechanical, by its very nature, breaks. Paddles have less that can go wrong with them. If you were in a remote area without outside contact, would you rather rely on paddles, or a slightly more efficient mechanical device?

Can I bring Macgyver or Tim Hancock with me?