T-Pain Is On A Boat: [Electric Boats] First impression of an electric sailboat

Monday, August 24, 2009

[Electric Boats] First impression of an electric sailboat

This weekend I had the opportunity to experience an electric sailboat in person. James Lambden, owner of Above the Waterline marine outfitters, arranged a "test drive" on a boat that his company converted to electric drive a few months ago.

The boat is "Vesper 1", a Serendipity 43 that displaces 17,000 pounds. The owner replaced the 55hp diesel with a drive system that includes an 8" Mars air cooled, open frame PMAC motor and a 70A controller hooked up to a 48V battery bank. The motor drives a 17" by 17" prop through an Emerson gearbox with an integral thrust bearing and a 5:1 gear reduction. You can find more information about the boat on James' website - http://www.propulsionmarine.com/vesper.htm . This boat has been able to generate 200W of electricity of prop driven regeneration through the Millipak controller.

The 12hp diesel in my 1964 Cheoy Lee Bermuda 30 ketch recently gave up the ghost and I am going to have to repower her. A new diesel motor will cost about $8000 on a pallet, and I figure that the total diesel project would cost more than $10,000 if I provided all of the labor myself. I'm hoping that a complete electric drive system will cost around half as much as the traditional solution.

Saturday afternoon, I met James at Channel Islands harbor in Oxnard, CA to check out one of his drives in action. After a quick tour of the installation; battery pack, drive, controller and solar charging system, we ran up the drive while still tied to the dock. Under full power with the drive fully exposed, the gears do make some noise, but the large prop and high gear ratio contribute to the overall volume. Replacing the engine cover quiets the system considerably and the addition of sound damping material should help even more. After casting off, the boat moved smoothly out of its slip and into the main channel. Picking our way through the many other boats in the harbor, the boat ran quietly. With a little more open room as the harbor got wider, the boat accelerated to about 3.5kts with just a little background noise from the drive gears. After about 20 minutes, we headed back into the slip and the drive hadn't pulled enough power from the battery pack to trigger the solar charger out of float mode.

As one can see in the photos on James' website, the installation is simple and elegant. While some people may worry about the loss of overall range under power, these systems seem to be excellent auxiliary drives which are designed to supplement the sails, rather than replacing them. I am going to move forward with getting my old diesel out of my boat and cleaning up the engine compartment. At this time, I believe that I will be working with James to develop a drive system that is tailored to my boat and my specific needs. With any luck, I'll be enjoying quiet and clean sunset harbor cruises with my friends before year end.

Eric Dysart
1964 Cheoy Lee Bermuda 30 "Serenity"
Marina del Rey, CA