Off Grid & Off Shore: Page 2 of 3

Sustainability at Sea

For cruisers, who generally sail in areas where the sun and wind are abundant, combining solar and wind power is a no-brainer—especially when the alternative is burning diesel fuel to charge batteries. “When you use the power of the wind to move your home,” Mike says, “you feel good. And when you can power the rest of your needs with renewable energy, it completes the picture.”

In 2003, after talking with fellow cruisers and observing different wind turbines at work, Mike purchased a wind turbine manufactured by Kiss Energy Systems (KES) in Chaguaramas, Trinidad. Designed for marine conditions, the KISS (Keep It Simple Sailor) turbine is durable yet quiet enough for the confined quarters of a sailboat. Elliptical blade ends minimize tip noise, while a 9-foot tower mounted to the stern provides plenty of headroom—nearly 7 feet.

Mike and Joanne saved on labor costs by installing the turbine themselves. Instead of using the mast mount kit offered by KES, they fashioned a mount from stainless-steel pipe—which cut costs some but added hours to the project. “Measuring, cutting, and fitting the turbine mount took several days. What made the installation more difficult was that we did it at anchor. It would have been much easier if the boat was on land or docked, but we managed,” Mike says.

Three blades make up the 58-inch-diameter rotor. The aerodynamic fiberglass two-piece housing is hand-molded in KES’s Chaguaramas shop, as are the blades. The manufacturing of the three-phase, permanent-magnet alternator is subcontracted to local fabricators. The alternator’s three-phase AC output is, in turn, converted to DC for battery charging. In typical 15-knot (17.3 mph) winds, the turbine can produce up to 7.5 amps for the 12-volt nominal battery bank. If batteries are full, the wind genny can freewheel or an electrical brake can minimize the rotation in winds up to 30 knots (34.5 mph). Stronger winds require the freewheel mode, and a thermal switch reduces the output and prevents the alternator from overheating.

Because the turbine does not include additional regulation  other than the thermal switch, manually furling the turbine is necessary to prevent excessive battery voltages. Mike does not worry too much about overcharging the batteries, since he’s never far from the boat for long. On the rare occasion when the turbine needs a break or, in trade winds, makes too much noise, he stops the rotor manually by switch. “If we’re lucky enough to make that much energy, it’s time to do some ironing, use the microwave, or make some other use of it,” he says.

Solar in Safe Harbor

“It’s a double-edged sword with wind,” Mike says. “We like the wind, and we need the wind, but we also like to get out of the wind.” Before, anchoring in low-wind spots or seeking shelter in harbors meant that the couple had to rely on the diesel generator. For that reason, Mike chose to supplement the wind generator with a simple solar-electric system—two Shell 80-watt PV modules mounted horizontally on the bimini (awning) over the cockpit. He purchased the modules from Marine Warehouse in Trinidad, and sourced from a local hardware store the electrical cabling and other parts—stainless-steel tubing, mounting brackets, and nuts and bolts that resist the corrosive effects of salt water.

Because the position of the boat is always changing and shadows are inevitable, the placement of the modules is not critical to the system’s overall performance. “On a boat, it’s usually a matter of finding free space where the modules are out of the way and won’t get damaged,” says Mike, who chose not to tilt the modules, and instead, flush-mounted them to the bimini frame. “I probably could have gotten slightly better performance if I’d made the mount adjustable, but the sun is so strong and the days are so long here that the slight gain didn’t seem all that important.”