Saturday, March 6, 2010

RE: [Electric Boats] propellers

 

But then it wouldn’t be regeneration, would it?

I mean, in order to spin the prop at the same speed as the boat, the motor has to spin the prop slightly (30-50%?) faster than it would spin, loaded and in the wake of the boat.

That’s not regen…any of our controllers can do that.

2cents-

-mt

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of aweekdaysailor
Sent: Friday, March 05, 2010 9:49 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] propellers

 

 

I believe, but can't yet prove, that the one area where "regeneration" might actually be practical is in what Kevin P calls "electrosailing" - matching the prop rotation to the boat speed so that it's regenerating about 50% of the time (very low wattage mind you) The point of this is not really regen, but rather nullifying the prop drag and getting the extra 1/2 to 3/4 knot of speed. Over a sufficient distance, this extra speed is the practical equivalent of a feathering prop (without the drawbacks) and nearly net zero energy use.

I currently have a 3-blade, so the above is more necessity than choice.

-K

--- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@...> wrote:
> I bet a large diameter, high aspect ratio 2 blade prop would give excellent performance as a sail aux drive, especially if a method could be devised to lock the prop in the vertical position hiding in the wake of the skeg. A folding prop that would work in reverse would be even better.
>
> Denny Wolfe
> www.wolfEboats.com
>

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