Pedal Powered Boats

[papawoodie]

Colin:

Good Luck,

Count on my support from the sidelines...

Will be following your progress and looking forward to each new update and report.

Have Fun, Enjoy, and Do Something you'll be remembering and sharing for a lifetime!

[Clemens]

Hello Colin,
I'm anxious to read your blog while you'll be on your big trip down south.
Congratulations, best luck!
Clemens

[joco]

i would love to see closer that kit
http://www.shuttlebike.com/ that someone post few weeks back.

the pedaling kit like that could be great in a kayak.

joco

[I57]

Almost completed my new boat and hope to have it on the water in the next day or so. I'm trying out the dipping rudders, they have a dual purpose of steering the boat (of course!). But also will be used as a stand for the rear of the boat when its sitting on the beach. The flexible shaft goes through the centre of the hull and is raised in shallow water, the dipping rudders keep the weight of the boat off the shaft. I'm using two long aluminium tubes to swing the rudders up and down, see how they work out.

Ian

[mihkel]

I was wondering, looking at pedal powered boats with propellers. Why put a propeller that might get stuck in grass and greates a lot of drag (not the propeller but the suporting contruction of it) - has anyone tried to but the propeller inside the boat - a water jet

[DougCim]

Originally Posted by mihkel

I was wondering, looking at pedal powered boats with propellers. Why put a propeller that might get stuck in grass and greates a lot of drag (not the propeller but the suporting contruction of it) - has anyone tried to but the propeller inside the boat - a water jet

A quick comparison of motorized outboard jet-drives shows that while they're generally better at avoiding debris, they're not as efficient overall. Typical figures claim a jet-drive conversion of a regular prop outboard engine "feels like" about 30% less power, while some say it feels like closer to 50% less.

If you want to avoid weed entanglement at all costs, the best drive would probably be a paddle-wheel. The main practical problem it has is that it's the most bulky type of "motor" drive there is, and that with the usual setup of using one single wheel spanning the width of the boat, there's no easy way to incorporate thrust-steering into it.

There is one company that builds a smaller model. It appears they use leading rudders placed at the forward end of the boat.
http://www.marshrider.com/

One of the ideas I tossed around was to use two side-by-side paddle-wheels at the rear of the boat, with canted paddles. The human-powered drive setup would allow driving each separately. Turning only one (or turning them in opposite directions) would cause the boat to turn, while turning both would make the boat go straight--but I don't know how big an efficiency hit you would take with the canted paddles.
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[tinhorn]

Originally Posted by DougCim

One of the ideas I tossed around was to use two side-by-side paddle-wheels at the rear of the boat, with canted paddles. The human-powered drive setup would allow driving each separately. Turning only one (or turning them in opposite directions) would cause the boat to turn, while turning both would make the boat go straight--but I don't know how big an efficiency hit you would take with the canted paddles.

Your idea sounds intriguing, but I'm not sure you'd need to cant the paddles in order to make this work. Think sidewheels, but mounted close together on the back instead of the sides.

I'm slowly turning an old 8' speedboat into a small pedal-driven sternwheeler. I'm at the point where I'm trying to replicate (or improve upon) the old-timers' method of four rudders ahead of the paddlewheel with a couple of "monkey rudders" (monkey see, monkey do) behind the wheel.

Hmmm....copied this from that Marshrider site linked above:

Both rear and side rudders were experimented with, leading to the same steering problems encountered with the long-shaft, stern-drive units.

Then, a revelation, why not put the rudder on the front! The maiden voyage of this prototype made clear several things. One, It worked, two, the front mounted rudder eliminated steering problems, three..We were really on to something.

[portacruise]

Interesting post, thanks. Some comments about my experiences below.

Porta

Originally Posted by DougCim

A quick comparison of motorized outboard jet-drives shows that while they're generally better at avoiding debris, they're not as efficient overall. Typical figures claim a jet-drive conversion of a regular prop outboard engine "feels like" about 30% less power, while some say it feels like closer to 50% less.

EFFICIENCY DOES DROP TREMENDOUSLY BECAUSE OF WATER FRICTION WITHIN THE JET DRIVE SURFACES. HUMAN POWER IS JUST TOO LOW TO MAKE WHAT IS ESSENTIALLY A REQUIRED HIGH HP POWER PUMP WORK AS A PROPULSION DEVICE. BESIDES GRASS CAN EASILY CLOG THE INTAKE SCREEN ON A JET, ESPECIALLY WHEN STARTING UP OR CRUISING AT SLOW SPEED. MANY TIMES I HAVE HAD TO HOP OFF A JET SKI TO UNCLOG THE MOTOR INTAKE SCREEN WHICH CAUSED PROPULSION THAT HAS COMES TO A DEAD STOP....

If you want to avoid weed entanglement at all costs, the best drive would probably be a paddle-wheel. The main practical problem it has is that it's the most bulky type of "motor" drive there is, and that with the usual setup of using one single wheel spanning the width of the boat, there's no easy way to incorporate thrust-steering into it.

I THINK A 'FLIPPER' DRIVE LIKE THE HOBIE IS THE MOST PRACTICAL(THOUGH STILL ENTANGLES SOMEWHAT) IF YOU'RE TALKING SUBMERGED DRIVE. OTHERWISE A HUMAN POWERED AIRBOAT PROPULSION WHICH I BELIEVE HOLDS THE CURRENT HUMAN SPEED RECORD WOULD BE THE WAY TO GO. http://lancet.mit.edu/decavitator/ PADDLEWHEELS ARE JUST TOO HEAVY, BULKY AND STILL TANGLE IN WEED WHEN SCALED TO MUCH LOWER OUTPUT OF HUMAN POWER, THOUGH SOME FAST ONES HAVE BEEN BUILT AND RACED. I WOULD RANK AN IMPROVED VERSION RICK WILLOUGHBY'S FOLDING PROP RUNNING WITH AN UNTETHERED FLEX SHAFT AS VERY PROMISING, AND POSSIBLY SURPASSING FLIPPER DRIVE IN SOME APPLICATIONS. HERE'S A VIDEO OF MY SYSTEM OPERATING IN VERY SHALLOW WATER: Prop Shaft Systems. SEE POST #54.

There is one company that builds a smaller model. It appears they use leading rudders placed at the forward end of the boat.
http://www.marshrider.com/

One of the ideas I tossed around was to use two side-by-side paddle-wheels at the rear of the boat, with canted paddles. The human-powered drive setup would allow driving each separately. Turning only one (or turning them in opposite directions) would cause the boat to turn, while turning both would make the boat go straight--but I don't know how big an efficiency hit you would take with the canted paddles.

INTERESTING YOU SHOULD BRING THIS UP. I BUILT A MODEL OF SUCH A DUAL PADDLEWHEEL, (BASED ON THE SUPER LIGHT JET BLADE) http://www.elements.nb.ca/theme/wate...lade/blade.htm AND FOUND IT ALMOST IMPOSSIBLE TO RUN A STRAIGHT COURSE! THE BLADES OF THE SEPARATE PADDLEWHEELS ARE NEVER EQUALLY SUBMERGED ON THE TWO SIDES, EXPOSING DIFFERENT SURFACE AREAS. THIS REQUIRES CONSTANT CORRECTION FOR STEERING WHETHER BASED ON FEATHERING OF ONE WHEEL OR CHANGING THE DEPTH OF IMMERSION TO COMPENSATE FOR THE CONSTANT IMBALANCE (TRIED BOTH METHODS). NEVER COULD MASTER IT WITH MY SHORTER HULLS, BUT MIGHT WORK WITH A VERY LONG AND MASSIVE ONE AS PICTURED. I ALSO DIDN'T LIKE THE NOISE, VULNERABILITY TO DAMAGE WHEN HITTING BOTTOM OR FLOATING DEBRIS AND GETTING SPLASHED BY WIND DRIVEN SPRAY....
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[portacruise]

Very clever setup Ian. Does your flex shaft run through a hollow open tunnel in the boat, or is it connected at the end of a bushing that runs inside the hull?

I run a much shorter pontoon with completely untethered flex shaft mounted on a quick release pivot which is turned side to side for steering. The whole assembly can be lifted off the pivot in seconds. Also the flex shaft disconnected in about a second from the quick release hex shaft if the boat will be beached. http://www.drillspot.com/products/58...rill_extension Here's a demo of the flex capability of the shaft: http://www.lashen.com/vendors/greenlee/hole_making.asp

Hope this helps.

Porta

Originally Posted by I57

Almost completed my new boat and hope to have it on the water in the next day or so. I'm trying out the dipping rudders, they have a dual purpose of steering the boat (of course!). But also will be used as a stand for the rear of the boat when its sitting on the beach. The flexible shaft goes through the centre of the hull and is raised in shallow water, the dipping rudders keep the weight of the boat off the shaft. I'm using two long aluminium tubes to swing the rudders up and down, see how they work out.

Ian

[DougCim]

Originally Posted by tinhorn

Your idea sounds intriguing, but I'm not sure you'd need to cant the paddles in order to make this work. Think sidewheels, but mounted close together on the back instead of the sides. ...

Side-wheels are obvious but they would either need to be rather narrow, or they'd end up making the boat rather wide overall. I wanted to build a boat no more than about 15 feet long and with a hull about 6 feet wide. Also, if they were placed at the rear on the sides, I don't know how much turning power you'd really have.

This is a diagram of what I was thinking of:
http://www.norcom2000.com/users/dcim...addleboat.html
(pic is only 67kb but a bit wide)

With the above type of drive, no sort of rudder is necessary. The paddle-wheels would be as wide as the boat hull, so it should still be efficient. When both paddle-wheels are rotated different directions, there's no net forward or reverse thrust, all that is produced is sideways thrust--so the boat should be able to basically rotate in place.
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[I57]

Portacruise
The shaft is housed in a PVC tube running through the boat. From the gearbox to the underside of the hull the shaft is rigid 16mm aluminium tubing with the 8mm flex shaft running to the prop.
Had the boat on the water yesterday and the dipping rudders were both dragging in the water, need to adjust the pivot point or raise it higher.

Ian

[tinhorn]

DougCim,
Bingo! That's what I envisioned, but I phrased it poorly. You don't want sidewheels mounted on the sides at the rear--the old-time spec for sidewheels was at a point 5/8 the length of the boat, measured from the front.

I still don't think you'd need canted paddles, though. If you're spinning the wheel, you'll get the motion, and I think you'd get better traction with straight, not angled, blades. There was some old info printed on angled blades that is included in this book: http://www.lulu.com/product/paperbac...nology/2390358 . (Don't tell anyone, but if you click the Preview link below the cover pic, you can download the entire book for free. S'okay--it's my book.)

I've never pedaled a contraption that didn't have a solid connection between pedals that were opposed 180 degrees. While your drive and split sternwheel are terrific ideas that I may steal for a future single-seater boat (my current project is a side-by-side two-seater), have you considered the potential awkwardness of unconnected pedals?

[DougCim]

Originally Posted by tinhorn

....
I've never pedaled a contraption that didn't have a solid connection between pedals that were opposed 180 degrees. While your drive and split sternwheel are terrific ideas that I may steal for a future single-seater boat (my current project is a side-by-side two-seater), have you considered the potential awkwardness of unconnected pedals?

Yes I have, I wondered about that as well. The double-rod drive system I imagined would not easily facilitate locking both drives "together".

Plus it is just bulky overall, but there's no way around that with a paddlewheel.

[tinhorn]

Bulkiness is a challenge--I've used every square inch of space squeezing a 32"x31" sternwheel into the existing hull of an 8' boat. I found an excellent old patent for articulating the paddles, but it would require smaller wheels for my project so I'm going with a larger wheel and static paddles.

Could your split wheels ride on clutches so that they could be individually slowed or stopped with a bicycle disc brake? It seems the slowed wheel would then act as a brake of sorts allowing turning but not spinning in circles. (Spinning would disorient me anyway.)

Info on Galloway's Oblique Paddle Wheel and my favorite, Buchanan's Parallel Paddle Wheel:

[DougCim]

Originally Posted by tinhorn

... Could your split wheels ride on clutches so that they could be individually slowed or stopped with a bicycle disc brake? It seems the slowed wheel would then act as a brake of sorts allowing turning but not spinning in circles. (Spinning would disorient me anyway. ...

Mine could not, since I was going to drive them with a pair of push-pull rods on 90º-cranks. The rods would function with much less noise than a chain-drive setup would, and to have the whole thing function quietly was one goal.

I don't think it would be all that much trouble to maintain straight lines in calm sheltered water; kayakers not using a rudder do it all the time. In more-open water I could just use a drop-down rudder on the front end to correct for wind/currents. The important thing here is that the rudder would ONLY be for deeper-water use, and so wouldn't interfere with running through weeds or in very shallow water.
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