In my role as a marine outfitter, I often ask people how they use their boat. If they motor around at hull speed all the time, and expect that to be the norm after an electric conversion, then they require a generator. If they sail everywhere, and wish to increase the performance of their boat as a motor-sailor, then electric propulsion is right for them. The amount of batteries, and charging sources then determine their range.
An electric sailboat is a better sailboat, conversely, a diesel sailboat is a better motorboat. The best of both worlds remains the diesel-electric hybrid.
My preference is solar electric propulsion.
Currently my Catalina 30, in calm conditions with no wind or waves, can motor under solar power alone at 3 knots. We call that "sunlimited range"! The 450 watt solar panel turns and pivots to focus on the sun. When stormy, it stows in the horizontal position for minimum wind loading. The array is controlled with actuators by a joystick. We are now experimenting with automatic solar tracking.
Having a solar electric boat gives a new sense of freedom. Just imagine getting to the doldrums and traveling at 3 knots right through them.
Adding 400 solar generated watts to the propeller, when Kapowai is sailing along in a light wind at 2.5 knots, increases boat speed to 5 knots. Kapowai is always a fast boat to solar sail.
An electric motor has so much finesse in low power ranges it can be counted with the inventory of the sail locker.
James
On Mar 18, 2012, at 10:43 AM, Mike wrote:
Rick:adding to John's point it's good to remember about cruising electric propulsion on a sailboat is that you have a sailboat. You really don't need any motor to go anywhere. Any propulsion you do add is gravy. I still cruise the same waters when I had my diesel and enjoy the experience much more and spend less time doing maintenace since converting back in 2008. Your question about not wanting to wait around for charging can be easily addressed by a small auxilary generator like a Honda 2000 or similar unit. I use it for charging while at anchor and also can motor along in calm conditions at 3 knots using 900 watts and my boat is 30 feet and 16,000 lbs. But, more often than not it is just standing by in case I need it. You could also install an in board marine diesel if you wanted too. Flexibilty and the ability to take advantge on new technologies as they come along are easy to incorporate into an EP system also. Adding things like wind and solar into the charging mix is quite easily done if one does not do it intially.Capt. MikeFrom: Dave Kellogg <inganear1@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Sunday, March 18, 2012 1:05 PM
Subject: Re: [Electric Boats] cruizing sail boats
John, again well said, I learned this a few years ago and would never go back. I'm in the process of converting my big boat (38 Island Trader) to electric, I can make my own power, can't make gas or diesel... Dave KFrom: John Francis <surv69@gmail.com>
To: electricboats@yahoogroups.com
Sent: Sunday, March 18, 2012 12:26 PM
Subject: Re: [Electric Boats] cruizing sail boats
As far as I'm concerned the only problem with electric motors is lifestyle. The infrastructure didn't need to exist for refueling..100 years ago the lifestyle was no motor and maybe a sculling oar.30-50 years ago it was gasoline and infrastructure to ensure refueling.Today(and in the future), it will be electric with virtually no infrastructure for a while, then when a viable infrastructure(and better batteries), exist, electric will be the way to go.I say today . . . and work with what works and what's available.I say slow sustainable speed under power( maybe about 2 knots or so).There's a speed figure for boats called "natural speed". I read about in a boat that came out about when outboard motors were becoming popular, and the formula involved calculation friction and derived a speed at which a boat can maintain(once reached), using almost no power . . . that is, the point when energy usage(to "maintain a speed") begins to greatly increase.If a person uses an electric motor smartly(which, for the most part, we don't want to have to do), the energy(watts) to maintain the progress of the boat can be made up with solar panels.BUT . . . of course . . . NO ONE really want's to go "slow" in a sailboat under power and EVERYTHING is valued at maintain hull speed or near HULL SPEED.You got to say goodbye to HULL SPEED being the determining "value" of an acceptable speed.LEARN TO SAIL and learn to live a more leisurely life(style) . . . THEN electric will be worth it.John Francis
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