Is there an electric propulsion system for real-world use?
Alex Pesiridis is chief engineer of the Marine Power Division of Solomon Technologies (727-859-4447), a leader in the development of electric and hybrid power-drive systems for the marine, automotive, and aerospace industries. A graduate of the University of Colorado with degrees in electrical engineering and physics, Pesiridis has designed electric propulsion for many cruising yachts, some of which carry no fuel at all, but rely only on solar panels and/or other means of recharging. The best system for “real-world” boats today is a hybrid, says Pesiridis, combining an electric motor with a large battery bank and a genset for recharging. Compact, quiet, high-torque electric motors need no reduction gears or transmissions, require no maintenance, and operate at about 90-percent efficiency across the rpm range. “A diesel engine is most efficient only at a specific rpm,” he explains. Because it develops high torque at minimum rpm, the electric motor can replace a diesel of three, four, or
