From: Steve Dolan <sdolan@scannersllc.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Mon, November 29, 2010 6:27:36 AM
Subject: [Electric Boats] RE: Folding Props in reverse?
Ok I think I found it at the EMP site http://www.ikanostech.com/index.php/propeller-size The new Solomons Tech site.
If you race, you are a candidate for a feathering prop. You can't race with your motor on, so you can't afford the drag created by running without the motor turning your fixed prop. Does that mean you can't buy Ikanos Technologies electric drive? Not at all. Simply use the same solution available to a racing sailor with a diesel auxiliary: a feathering prop. It works fine with Ikanos Technologies drive and can still regenerate electricity under sail. (See Regenerative Motor Sailing.) Note, however, that the blades must feather and be able to lock in the open position. A folding prop, whose blades typically will not lock open, cannot be used for regeneration. The force of the water from sailing folds the blades back instead of turning them.
The blades of a feathering prop, however, can be opened in reverse orientation by running the motor briefly backwards until the prop blades lock open. The prop and motor then freewheel and regenerate just as well as they do turning forward. Water pushing against the blades holds them open. To start motoring again, the motor control lever is switched to forward. The blades flip back to normal orientation and push the boat ahead. To sail without regenerating or any motor use, the racing helmsman places the motor in neutral. The blades feather as they are designed to do, with their orientation parallel to the water flow.
Any thoughts??
Steve (still thinking this AM) in Solomons MD
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