Mirage vs Propel (Tug O War)

Just recently posted...

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Just a "smug, no contest" came to my mind before the video started!
The Hobie Mirage drive is the class leader of human pedal powered kayaks.

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Dr.SteelheadCatcher
Warrenton, OR

Nice!
(but the guy in the propel didn't look like he was trying very hard lol)

I think he is trying... the motion to pedal the Propel is odd and difficult. It has different resistance in different parts of the stroke. You can see that clearly in the second one.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

yes, I think I mistook the resistance for a slow pedal stroke.

I found the action of the propel to be very comfortable and not difficult at all, HOWEVER………………………………………………….
The problem with the propel is that there is a point where the propeller blade will suffer from cavitation, meaning there is a limit to the speed and power no matter how hard you pedal. If you push it hard there will be no further increase in speed or power.
Currents cause a big problem for the propel because of these limits. It's fine in perfect conditions.
The mirage drive performs very well in all conditions, especially against the current, because the only limitation comes from the fitness of the user not the drive itself. If you are a fit person the mirage drive will allow you to push through very tough conditions and go as fast as your fitness allows. NO CONTEST!!!!!!!!!!!!! Mirage all the way.
The only benefit I can see in the the propel is instant reverse capability.
Here is a short video of my Pro Angler 12 pushing through at a good rate of knots against the current and the wind. No problem.
https://www.youtube.com/watch?v=N1mxiquTIn0

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2021 Dune Hobie Lynx

We have never had a tug of war in a closed water tank nor used a propel.

However 2 different situations showed us how powerful, secure and safe our Mirage 2009 Oasis is.

Both of these events happened while my wife was still working. Due to her schedule, we were on the water after prime time re wind and plus a strong tidal impact on trip #2.

#1. A local lake, popular with yakkers gets a lot of heavy wind in the late afternoon. We went up later than I wanted to, due to my wife's schedule with another couple in non Hobie Yaks. We went into a protected cove at that time with a mild wind at our backs. About an hour later, when we decided to head back home, the wind had really picked up to about 20 mph and the waves were about a foot high.

We headed into the wind and got some protection from a shoreline for a while. When, we left the cove's protection, our lady friend was having trouble staying on course and gaining distance. We had no ropes to pull her. She got as close as she could behind our Oasis and we broke the wind for her. Her husband did the same. We finally got to a spot where she could hug the shoreline and still go ahead. We stayed with her and were dry and able to maintain our course thanks to the Mirages. Both of our friends were wet, cold and exhausted.

#2. Again, later than I wanted to go, my wife and I went on our local river. Instead of going downstream against the wind with the tide and flow, my wife wanted to tour an area upstream in a protected cove. We got to the cove quickly and had a great time.

On our way back, we hit higher/stronger winds and a powerful upstream tide. We pedaled hard and did some close to shore navigation to get out of some of the wind. We came on a group of yakkers taking a lesson. Their leader/instructor took them to shore to wait out the wind. That was part of her lesson re when not to go. We got to our launch area and called her on a cell phone. She and the other yakkers were okay and staying on shore out of the wind. They got back to the launch site okay about two hours later. Our legs were tired, but thanks to the Mirages and the stability of our Oasis, we were okay and dry.

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2009 Oasis
2012 Freedom Hawk Pathfinder

Thinking aloud here:

So, being the Mirage Drive is so much more efficient than a propeller, why are all kayak power kits based on propeller systems? When will Hobie come out with a POWERED Mirage? A motor head instead of pedals.



(You can send me my royalty checks starting now, LOL!)

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Cleverly disguised as a responsible adult
Pro Angler-14 owner

1. Props can be more efficient than Mirage Drives, but only in a narrow operating range defined by RPM, weight and speed. In practical use, the various demands on props make them a compromise. The biggest limitation in props IMO is their fixed pitch angle.

2. Props move in one direction in a rotary fashion and so do electric motors. The connection is pretty simple and compact -- it's a good marriage for power applications. Props were designed for motors and adapted for legs; Mirage Drives were designed for legs.

3. The Mirage Drive advantage is its variable pitch fins (or blades), giving it more efficiency over a larger operating range. The same unit can give stump pulling torque off the line (so to speak) and high speed thrust. This is also quite apparent on a typical leg stroke profile. If you've tried a Propel, you noticed you have very little power at full leg extension and flexion (approximately 3 and 9 o'clock positions). There is no flywheel so prop speed varies significantly during your stroke. It sounds like this: WHIRRRR when spoken. Speed up the tempo and you can sinc up it with the video . The Mirage does this as well, but is quieter because there is no whir sound AND its variable pitch keeps it pulling efficiently without stalling (cavitating).

Many proponents tout that the instantly reversibility of the Propel, and for some that is important. On the other hand, very few notice that Mirage Drives can be operated in shallower waters. And for those who are persnickety, Mirage Drives out glide props (including eVolves) -- significantly.

I was half kidding with my suggestion (but only half.) As a pilot, I'm well versed in the advantages and disadvantages of a propeller. I also understand the difficulties of converting reciprocal to rotary motion - or vice versa.

On the other hand, simple gearing would change a high-rpm low torque motor to a low rpm high-torque reciprocal motion ideal for a mirage drive. Oh, and the lack of power at the 3 and 9 o'clock positions of the cranking gear would be ideal for a reciprocal system; you'd want minimum power at the blade reversal point and maximum at mid-stroke. Add a variable speed controller to the motor and you're set.

Is a motor and prop system simpler than a "flapping wing" system? Oh, heck yes. But Hobie seems to have engineered the latter pretty well so far, no?

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Cleverly disguised as a responsible adult
Pro Angler-14 owner