Some of us have or are considering re-powering our Dolphins. This is an effort to provide information on the electric power alternative, not an effort to promote it or to promote any specific system or manufacturer. We will keep adding interesting articles or comments

After some research, early in 2007 I contacted a small company in Indiana, Re-e-power, that seemed particularly helpful with information specific to sailboat powering. These motors are 'inboards' not unlike sail drives. Click to go to their website - http://re-e-power.com/aboutus.html

The following is an exchange of emails and products information in February, 2007 that your webmaster had while considering power options for Passage - a decision not yet made.

Date: Tue, 20 Feb 2007 11:33:32 EST

Hi
I have 2 Dolphin 24 sailboats. They are about 4500lb displacement MORC boats designed and built in 1960. One is completely restored and powered by a 4hp OB inside a transom well. It weighs 32! lbs and is stored beneath the cockpit when racing or cruising. It has a power prop and will push the boat to 4.7 knots in a flat sea, no headwind - half that in a medium chop and headwind. With one filled 3 gal tank there is 5 hours of operation. There is a 60 lb, 97 amp gel battery to power electronics, auto pilot, lights, etc. Altogether about 120lbs. With an additional 6 gal tank, about 40 lbs, I get 15 hours of operation and have extensively cruised this boat up and down the NE coast. Total cost around $1200/1300.

The second boat is undergoing restoration now and had a rebuilt Palmer 9hp inboard gas engine. We are re-considering the power options. Simple and easy is the OB option but, even though it is light, there is the hassle of removing it from the well and storing below, especially in bad weather or single handing.

Noise, emissions are issues.

Some questions -

Have you done any development work with folding props? My pretty thin profile OB shaft and prop cost about .4/.5 knots in lost speed thru the water which is why it comes out when racing or longer distance sails. What does your pod/prop cost in terms of speed when sailing? How much does it weigh?

This particular boat will be used for day sailing and have a slip with power for recharging. I have estimated that its normal power use will be in and out of the slip and sailing within 15 minutes, sailing for a few hours and back. Run out of wind and maybe have a 2-3 hour motor back. I think 5/6 hours "normal use" running time would be sufficient. How much battery capacity/weight would be needed?

Have you made any sales or have user references in the CT/RI area?

Thanks

Ron Breault

Old Lyme, CT

Their reply follows

Date: 2/28/2007 6:59:06 AM

Hi Ron,

Thanks for inquiring.  Our System 2500 would give you comparable performance to the 9 hp outboard. 

A folding prop will fit on the -PB model.  It has a 1 inch shaft with a standard taper, so most any standard inboard prop will fit.   Of course you will lose the advantage of re-charging the batteries under sail.

The pod, with the prop in generator mode will cost .25-.5 knots depending on how the prop is adjusted.  With a folding prop you will see about .2 knots difference.  The other option would be to use what we call zero thrust feathering.  This is where you put just enough power (about 1/4th amp) to the unit to take away the drag without really adding to the thrust of the boat.  If you have a small solar panel it will take care of the extra power required to do this for days. The unit weighs 77 lbs.

 
Three group 31, 12 volt batteries will handle your power needs and each of them weigh in at about 70 lbs.  So total weight of the whole system would be less than 300 lbs or if you have an onboard charger, just about 300 lbs even.  With a DC/DC converter, you can run your house needs (lights and such) off of the motor battery pack

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Erik Evens (Robin) sent in the following email and link to a Swedish company that makes a true inboard with recharging through the prop. He sent in the following email.

Nice start on the section on electric power.  The Re-e-power units look
powerful, but I can't imagine bolting something like that to the underside
of a Dolphin.  I immediately thought that if you could mount the pod to a
strut that had a clamp at the top, you could use it as an electric inboard,
and mount it in the motor well of a Dolphin.  The thing weighs 50 lbs,
though.

Here's a Swedish company I've been looking at for a while:

http://www.ozmarine.se/OZecoDrive/Eng/IndexOZecoDriveEng.html

They make a true inboard system that looks like it has all the features of
the pod-people's product, including regenerative charging.  Expensive, but
looks really viable.

-EKE

Erik Evens

Click the following link to go to their very interesting website

http://www.ozmarine.se/OZecoDrive/Eng/IndexOZecoDriveEng.html

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The website BoatDesign.net has a collection of electric power websites for those that are into self education.

Click http://www.boatdesign.net/Directory/Propulsion/Electric/

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