T-Pain Is On A Boat: Re: [Electric Boats] Regen

Thursday, June 11, 2009

Re: [Electric Boats] Regen

There are a few other considerations for regen that may not be apparent. The design of the cutlass bearing and stuffing box in a traditional snailboat are optimized for pushing the boat. The water pressure is equal behind the prop, or at least balanced against the rudder, keeping lateral forces from excessively wearing the cutlass bearing. In regen, the water is pulling on the prop, and as the water is sliding over and up the hull, the angle of attack is not even close to axial. As a result, the cutlass bearing must resolve additional side loading. In systems using ball bearing and seals, such as the Re-e-power, regen can be achieved without comprimising existing tradional hardware.
The most reliable...? Mount an alternator to the stern rail, and tow a prop on a rope. The alternator will charge the batteries at many times the rate of a motor in regen braking. The prop is spinning in clean water, and can make power from just a knots.

Arby

________________________________
From: aweekdaysailor <aweekdaysailor@yahoo.com>
To: electricboats@yahoogroups.com
Sent: Friday, June 12, 2009 7:58:03 AM
Subject: [Electric Boats] Regen

There is only one possible conclusion.. .

...Golf carts should have sails!!

Seriously though...I do think that eventually regen can get practical (my "X-prize" standard is 10:1 ratio). But you probably need some combination of (as mentioned many times)

o fancy controller to auto-feather without stalling
o Optimized prop design that can generate lift in reverse
o Over-sized (and therefore probably pod-mounted) and maybe shrouded/ducted props - note: these need to be running all the time while sailing or the drag would be too great, so technically you're now a powerboat.

That's why I call it a science experiment - if you've got more money and time than common sense you'll be a perfect candidate!!

But consider - if this really worked there would already be a tow-generator on the market that would make stupendous claims about how much power they generate (in reality a good one gives 6-8amps @12V - about 100watts*... ) House power? Sure. Propulsion? Nah.

-Keith

(* references: http://www.jgtech. com/pdf/aqua6gen _instructions. pdf )

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