I'm interested in your post on this motor. I looked at it on the hobe web site. How were you planning to attach the drive. Will it fit into the daggerboard trunk? Dan 

The Hobie motor attaches/clamps to thier kayak rudder blades.  It could be modified to fit other rudder blades or the dory rudder blade could be modified to accept the Evolve.

Wow, the Hobie Evolve is a pretty pricey accessory!

All high performance electric motor systems are pricey, not just  Hobey and not just boats. The good old electric fishing motor powered by lead-acid batteries has been around so long that it can take advantage of economies of scale, that's why it's so cheap. It's also heavy as heck. The modern kayak motors/batteries have much more power and range per pound and fit in a much smaller space. That's what you're paying for.

High energy density lithium batteries and ridiculously efficient electric motors packed in a small salt water-proof package are bad enough, but then when you add in the fairly tiny (compared to cars and cell phones) market size, you can't get a low price. Especially if you factor in that this is all new technology, so even the companies that are just using the technology (instead of inventing it) are still at the front end of the amortization curve for development costs.

In the meantime, I've often thought that since I'm a builder, I could try building an electric motor system. A nice brushless motor, comercially available prop, homebuilt motor controller using one of the many cheap single board computers, a battery pack made up of power drill batteries and the whole thing packed into a nice watertight enclosure. Maybe even built into the boat in such a way that it is concealed from the water police's view so I don't have to register my boat and pay taxes on it. With my free labor it should be quite affordable for me, but no one could afford to buy it (just like a homebuilt boat).

Happy Thanksgiving all,

Laszlo

 The Evolve will fit in the Marage "well", but that's a pretty wide opening.

For NE Dory probably easiest to build a new "rudder" with Evolve intergrated, but the rake of the rudder post would make for interesting geometry. 

   Nancy's China DC has a raked rudder and integrated electric motor integrated. 

http://store.devlinboat.com/nancyschinadc.aspx

Zach Wiest integrated an trolling moter and a Skerry rudder

http://skerry.knowpatience.com/category/electrical/

I wonder how i works while sailing.

Ruud

I'm not saying it can't be done successfully, but with a strongly raked rudder post, as the rudder is turned,  the thrust from the motor will increasingly be directed upwards rather than parallel to the surface of the water. Might require a light touch on the "throttle" when steered sharply, which wouldn't be unreasonable anyway.