Pedal boat drives, talk about yours

[MarkX]

In my case, a bent shaft arrangement isn't ideal because the whole prop drive has to be retractable/removable in case I need to come in on surf and smack down on a beach, get line tangled around the prop or if I need to paddle instead of pedal. My Kayak/Canoe will need to be a sturdy working boat designed to safely cope with unexpected sea conditions and curious shark nibbles (chewed prop), not a cruising or racing one for relatively smooth water. Shark attack is extremely unlikely but many world record ones have been caught where I plan to fish so I'm designing for peace of mind.

Maybe the universal joints supplied for socket sets are of use to those who do want to use a shaft at an angle.

[Guest625101138]

Originally Posted by MarkX

In my case, a bent shaft arrangement isn't ideal because the whole prop drive has to be retractable/removable in case I need to come in on surf and smack down on a beach, get line tangled around the prop or if I need to paddle instead of pedal. My Kayak/Canoe will need to be a sturdy working boat designed to safely cope with unexpected sea conditions and curious shark nibbles (chewed prop), not a cruising or racing one for relatively smooth water. Shark attack is extremely unlikely but many world record ones have been caught where I plan to fish so I'm designing for peace of mind.

Maybe the universal joints supplied for socket sets are of use to those who do want to use a shaft at an angle.

You will find universal joints awkward to pedal and prone to breakage compared with a curved shaft.

I have developed the curved shaft and folding prop to be virtually immune to damage from striking solid objects. It achieves this by being compliant. It simply bounces off things. I struck a number of logs in last year's Murray Marathon and there was no damage to prop or shaft. The previous year with the rigid prop on the curve shaft as shown in the V11 photo I bent the blades twice. In the worst case I has to stop and straighten the blade.

The set up I now have is less prone to damage and weed collection than the Hobie flappers.

The attached photos should give you an idea. The spring steel can be curved into quite a tight radius before yielding. If you yield it you can straighten it out by eye so it works OK.

The prop can also operate without a strut but this limits the ability to reverse.

The stern mounted outboard shown earlier can be made to kick up as well to protect itself.

Rick W

[MarkX]

Looking at your interesting setup in the left pic, I think it could be adapted to a fishing canoe/kayak by making the strut liftable and the angle gear swivelable.
In fact, a diy builder could use the complete head from an angle grinder (with a bit of modification) as it's above water.


Other question: I notice that the pedal cranks seem to be very high up from the deck on most boats. Bearing in mind that a fishing Kayak is a workboat rather than a racing machine, what's the minimum distance between pedal and deck one can get away with?

[Guest625101138]

Originally Posted by MarkX

Looking at your interesting setup in the left pic, I think it could be adapted to a fishing canoe/kayak by making the strut liftable and the angle gear swivelable.
In fact, a diy builder could use the complete head from an angle grinder (with a bit of modification) as it's above water.


Other question: I notice that the pedal cranks seem to be very high up from the deck on most boats. Bearing in mind that a fishing Kayak is a workboat rather than a racing machine, what's the minimum distance between pedal and deck one can get away with?

You really do not need to have the strut liftable. Just leave it free to move up so it can ride over bumps. If the blades hit something you stop pedalling and let the prop ride over.

Average person needs the crank 300mm to get heel clearance if you use cycle shoes. A trained recumbent cyclist can get away with about 250mm.

I have modified the deck on my latest design to get a slightly more upright seating as most non-recumbent riders find it unnerving. I quite like the very reposed set-up I use because there is more weight on my back than bum. I do not get bum rash like the kayakers.

Rick W

[MarkX]

On a SEA fishing Kayak the prop has to be reachable because line WILL get tangled around it sooner or later for certain. Preferably it should be completely retractable while landing a fish because if it does get tangled it'll probably be lost and you have to clear the prop anyway. If it's a big fish then it could be even more of a problem. If the drive breaks you have to paddle home too.
With Sea fishing safety has to come first, one can't just swim to the nearest bank. If the weather turns one can't be dealing with line in the prop. There's also stuff like jellyfish, and you sure don't want to clear something like that with bare hands.

Thanks, I'll probably go for 280mm clearance initially then. This first drive will be a test bed.

[portacruise]

Originally Posted by MarkX

On a SEA fishing Kayak the prop has to be reachable because line WILL get tangled around it sooner or later for certain. Preferably it should be completely retractable while landing a fish because if it does get tangled it'll probably be lost and you have to clear the prop anyway.

YES, I HAVE A RETRACTABLE MOTOR UNIT WITH MY PONTOON WHICH I CONSIDER A NECESSITY WHEN FISHING. MY HAUNTS ARE NOW RIVERS RATHER THAN THE "FLATS" AT THE COAST, SO I HAVE OPTIMIZED MY CRAFT SIZE AND DESIGN ACCORDINGLY. CONSIDERATIONS ARE NOT LIMITED TO FISHING LINE INTERFERENCE, AS ANYTHING THAT HAMPERS THE PROPULSION AND MANEUVERING CAN TURN OUT TO BE LIFE THREATENING, EVEN ON RIVERS, MUCH LESS THE SEA.


If it's a big fish then it could be even more of a problem. If the drive breaks you have to paddle home too.

I'VE LANDED FISH THAT WEIGHED CONSIDERABLY MORE THAN MY CRAFT. YOU WILL MOST LIKELY NEED A SECONDARY MANEUVERING SYSTEM AFTER YOU RETRACT YOUR PRIMARY PROPULSION, ESPECIALLY IF YOU DON'T HAVE THE STABILITY OF A PONTOON AS I HAVE. IN MY CASE, I HAVE GOOD ROD HOLDERS PLUS 2 HANDS FREE AT ALL TIMES TO PLAY A FISH, SINCE I CAN STEER THE PROPULSION MOTOR WITH MY LEGS. IF I DO PULL UP MY MOTOR UNIT, THEN I CAN DROP DOWN MY LEGS AND PADDLE TO INSTANTLY ROTATE THE CRAFT ON ITS AXIS IN ANY DIRECTION AS NEEDED TO FACE THE RUNNING FISH, WAVES, WIND, SUN, WHATEVER.

With Sea fishing safety has to come first, one can't just swim to the nearest bank.

ON RIVERS, IT'S RAPIDS, LOW HANGING LIMBS, BARBED WIRE, AND SHARP ROCKS WHERE YOU CAN LOSE EVERYTHING. AT LEAST YOU CAN USUALLY SEE IT COMING EXCEPT FOR FLASH FLOODS. BUT YOU MAY ONLY HAVE SECONDS TO READ THE WATER CORRECTLY, TO AVOID GETTING HURT.


If the weather turns one can't be dealing with line in the prop. There's also stuff like jellyfish, and you sure don't want to clear something like that with bare hands.

RICK'S FOLDING PROP HAS SURVIVED ENCOUNTERS WITH JELLIES, FROM ONE OF HIS PREVIOUS POSTINGS. MAY WANT TO TEST ON FLOATING MATS OF HEAVY SEA WEED IF YOU'RE GOING OUT DURING THAT SEASON.



Thanks, I'll probably go for 280mm clearance initially then. This first drive will be a test bed.

Hope this helps, see comments above.

Porta

[MarkX]

Good points, Porta, the more info the better.
This will probably be one of my launch points for testing:
http://www.enciclopedia.com.pt/image...to%20Amaro.jpg

And here will probably be the main launchpoint:
http://maps.google.co.uk/maps?hl=en&...06893&t=h&z=18

As you can see they are cement ramps and I have to take any drive off during launch+landing. The are very slippery too.

[MarkX]

Just won a batch of five dead 9" angle grinders on ebay which I will strip of their bevel gears. Not quite made up my mind yet as to exactly what I will do (so many options!) but I'm leaning towards bevel gears and shafts suddenly, one on the propshaft and one on the cranks with a shaft going up vertical. This would allow for the thinnest skeg, under 19mm or 3/4" with a small bulge where the bevel gears go for the propshaft.

I have seen the twisted chain arrangement but am dubious about the strength of 1/4" or 6mm chain and the thickness of skeg required.

[I57]

I use one of the Involute gear boxes at 1:3.3 ratio directly fixed to the flexible shaft. The setup is simple and straightforward which is less things to go wrong. I have a mounting frame fixed to the boat and bolt the gearbox on at setup to make transport easier. I lift the 8mm flex shaft up by hand to beach the boat and also it enables me to reverse, the prop is 400mm dia.
I have tried chains and universal joints with varying degrees of success, but my current setup has been the most trouble free. I don't use a skeg on the flexible shaft and have found even with weed wrapped around the hub speed is not greatly affected.
The involute gearboxes are heavy but they will take a lot of load and are reliable. The cost is about the same as buying a cheap mountain bike.