I thought only brokers peddled boats.

;-P

Steve "been pedalling bikes for years...."

I just tore the pedals and rod out of a discarded kid's toy with the idea
of some day installing foot operated paddles on one of my one sheet boats.

Prelimary thoughts are -

1. to be able to drift into shallow water only two paddles per side at 180
deg. so they can be held horizonal entirely clear of the water. set up a
shock cord to hold the peddals in place with the paddles horizontal out of
the water.

2. to avoid as much as possible pushing down on the water, use a bent
paddle shaft.

3. to mimic arm paddling have the blades on both sides enter teh water at
the same time - paddle, glide, paddle, glide - instead of constant churning
of the water.

4. to allow a combination of foot peddaling and double blade arm paddling
have the option of the foot paddles on each side 90 deg from each other
instead of parallel. imagine the power with both feet pedalling and arm
paddling at the same time - tandem paddle solo power kayak.

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I remember someone a while ago adapted a peddle drive to one of Gavin
Atkin's mouseboats and was quite happy with it. He used a "surfbike" drive.

Try this link if it works for you -
http://groups.yahoo.com/group/mouseboats/message/1906

--
Andrew Butchart

http://www.abutchartconsulting.com/sailing/ - The Floating Bear

"Bob La Londe" wrote in message
...
I have wondered about the efficiency of peddle power.

Glen-L has a nice design for a peddle powered boat, and there are numerous
peddle powere ABS plastic boats available for sale at moderate prices both
on-line and in the local big box stores.

They all have one thing in common. They use a paddle wheel for
propulsion.
I can see the obvious simplicity in design. A chain from the pedals to
the
drive axle and its ready to go. In almost all other craft though a
propeller desing seems to be more efficient.

From big ships to small pleasure craft the propellor seems to be the rule.
For a small peddle powered craft would a prop design make the best use of
the available power as well? How in the world woudl you go abotu figuring
out the optimum size and pitch prop for an application like that?







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Stephen Baker ) writes:
William says:

3. to mimic arm paddling have the blades on both sides enter teh water at
the same time - paddle, glide, paddle, glide - instead of constant churning
of the water.


Gonna kill your legs, Will. Much better to have a constant pedalling pressure.
Try riding a bike where half of the chainring (front cog) has no teeth. ;-)

no moreso than paddling kills your arms. and legs are stronger than arms.
the only problem I can see is the weak mechanical advantage of the small
diameter rotation of the kid's toy crank. like having the peddal crank on
a bike smaller than the cog wheel on the axel. the paddle shaft would have
to be short as feasible. hadn't considered that.

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William R Watt National Capital FreeNet Ottawa's free community network
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William Watt says:

no moreso than paddling kills your arms.

Not so - paddling kayak-wise uses a full movement of the arms, ending with the
paddle being withdrawn and the other arm starting to work. No jarring.
Having a blade come out of the water while still under full power, then (say)
half a revolution until the other blade hits is going to be..... hmmmm -
looks for marine analogy.... like NOT having a throttle-man on an offshore
powerboat. The prop will come back into the water after a jump with the engine
spinning maddly, suddenly get loaded and break the shaft/blade whichever. Not
good. ;-(

the only problem I can see is the weak mechanical advantage of the small
diameter rotation of the kid's toy crank. like having the peddal crank on
a bike smaller than the cog wheel on the axel.

THat situation is directly analogous to the kayak paddle, where the lever of
the arm to the fulcrum (other arm) is less than the fulcrum to the blade.
Makes the most use of the minimal power available frm a human body. Lance
Armstrong at peak produces 600Watts when pedalling.

the paddle shaft would have
to be short as feasible. hadn't considered that.

See above.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

I always thought about getting an old sailing cat, mounting a pushbike
frame on it, and feeding the drive through a secondhand outboard leg
mounted to the rear crossmember. Mind you, the paddle wheel thing would
be dead easy for a cat.
It would be cheap to do, and you would have a fast, roomy boat. Add
bike frames as you gain passengers!

Andrew.

Bob:

We have a number of pedal-powered boats in the "Fun Boats" section of
the web site.

http://www.dngoodchild.com

Cheers,

DNG

Bob La Londe wrote:

I have wondered about the efficiency of peddle power.

Glen-L has a nice design for a peddle powered boat, and there are numerous
peddle powere ABS plastic boats available for sale at moderate prices both
on-line and in the local big box stores.

They all have one thing in common. They use a paddle wheel for propulsion.
I can see the obvious simplicity in design. A chain from the pedals to the
drive axle and its ready to go. In almost all other craft though a
propeller desing seems to be more efficient.

From big ships to small pleasure craft the propellor seems to be the rule.
For a small peddle powered craft would a prop design make the best use of
the available power as well? How in the world woudl you go abotu figuring
out the optimum size and pitch prop for an application like that?

Stephen Baker ) writes:
William Watt says:

no moreso than paddling kills your arms.

Not so - paddling kayak-wise uses a full movement of the arms, ending with the
paddle being withdrawn and the other arm starting to work. No jarring.
Having a blade come out of the water while still under full power, then (say)
half a revolution until the other blade hits is going to be..... hmmmm -
looks for marine analogy.... like NOT having a throttle-man on an offshore
powerboat. The prop will come back into the water after a jump with the engine
spinning maddly, suddenly get loaded and break the shaft/blade whichever. Not
good. ;-(

I'm not actually looking for a continous kayak-style power, but a
discontinuous canoe-style or a discontintuous oar-stlye power. I've seen
foot-operated oars in a film on Southeast Asia.

I'm not looking at a bunch of little blades churning up the surface, but
two larger blades deeper in the water like on a canoe. I want the boat to
go smoothly and silently like a canoe, not making a lot of noise like the
peddal paddle boats I've seen. A slower action with larger, deeper blades.
Low rpm's, larger blades, more effective power.

I don't think the kids peddal shaft allows enough piston action in the
legs to work the large paddles.



--
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homepage: www.ncf.ca/~ag384/top.htm
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Hobie Cat makes a pedal system for their kayaks that is like a set of wings
flapping under the boat. I've never tried it myself but it looks like an
interesting idea.

http://www.hobiecat.com/kayaking/index.html

- Scott

"Bob La Londe" wrote in message
...
I have wondered about the efficiency of peddle power.

Glen-L has a nice design for a peddle powered boat, and there are numerous
peddle powere ABS plastic boats available for sale at moderate prices both
on-line and in the local big box stores.

They all have one thing in common. They use a paddle wheel for
propulsion.
I can see the obvious simplicity in design. A chain from the pedals to
the
drive axle and its ready to go. In almost all other craft though a
propeller desing seems to be more efficient.

From big ships to small pleasure craft the propellor seems to be the rule.
For a small peddle powered craft would a prop design make the best use of
the available power as well? How in the world woudl you go abotu figuring
out the optimum size and pitch prop for an application like that?

(William R. Watt) wrote in message ...
Stephen Baker ) writes:
William Watt says:

no moreso than paddling kills your arms.

Not so - paddling kayak-wise uses a full movement of the arms, ending with the
paddle being withdrawn and the other arm starting to work. No jarring.
Having a blade come out of the water while still under full power, then (say)
half a revolution until the other blade hits is going to be..... hmmmm -
looks for marine analogy.... like NOT having a throttle-man on an offshore
powerboat. The prop will come back into the water after a jump with the engine
spinning maddly, suddenly get loaded and break the shaft/blade whichever. Not
good. ;-(

I'm not actually looking for a continous kayak-style power, but a
discontinuous canoe-style or a discontintuous oar-stlye power. I've seen
foot-operated oars in a film on Southeast Asia.

I'm not looking at a bunch of little blades churning up the surface, but
two larger blades deeper in the water like on a canoe. I want the boat to
go smoothly and silently like a canoe, not making a lot of noise like the
peddal paddle boats I've seen. A slower action with larger, deeper blades.
Low rpm's, larger blades, more effective power.

I don't think the kids peddal shaft allows enough piston action in the
legs to work the large paddles.

I have often thought of using a track like a snowmobile that ran most
of the length of the boat, it could run under the boat and be pretty
shallow. You would have constant power, forward and reverse, and if
you kept the track under the boat, you could probably make it pretty
quiet. Also maybe using a softer material for the "paddles" you could
make it quiet too. If I were going to build it I would probably use
some sort of canvas with leather or rubber blades every 6-8 inches or
so. For a small boat, you would not need very big blades and this
could almost be done within the exterior limits of the hull itself
without even hanging out the bottom of the boat like a prop or paddle
wheel. What do you all think of that??
Scotty from SmallBoats.com