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

Saturday, March 6, 2010

Re: [Electric Boats] propellers

Plus,

1) you'd not be doing the diesel any favors letting it idle all day long;

2) any ICE is incredibly inefficient generating just a few percent of its rated power. The fuel you use maintaining an idle speed is 100% wasted, i.e. producing no useful work. That's why hybrid cars turn the engine off when the vehicle is stopped.

Denny

----- Original Message -----

From: Mike

To: electricboats@yahoogroups.com

Sent: Saturday, March 06, 2010 7:30 AM

Subject: Re: [Electric Boats] propellers

This is something I am interested in trying as well. Since I can not add a larger prop without a lot of work and $$$ the electro sailing concept does sound it might be the next best thing to regen. More speed without a lot more energy is a good thing for a cruising sailor. The ability to finely adjust prop rotation from 0 to max is something that you easily can do on an electric boat but, not a diesel. Since we will NOT be using the prop to push the entire weight of the boat through the water because we just want to negate the prop drag hopefully minimal energy would be needed. At least it will be an interesting experiment to try.

Capt. Mike

http://biankablog.blogspot.com

--- On Sat, 3/6/10, aweekdaysailor <aweekdaysailor@yahoo.com> wrote:

From: aweekdaysailor <aweekdaysailor@yahoo.com>
Subject: Re: [Electric Boats] propellers
To: electricboats@yahoogroups.com
Date: Saturday, March 6, 2010, 5:49 AM

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
>