Breeze On!

Wind generators have a natural appeal to sailors in need of extra power. They harness the same element that we rely on to get from A to B, and the technology behind them is well proven and reliable. Despite the growing popularity of hydrogenerators and ever more efficient solar panels, wind generators are still a common sight on bluewater cruising routes.

At the outset, it’s important to note the advantages and limitations of wind power for keeping the batteries charged. On the plus side, the generator will keep pumping out power at anchor or in port, as well as on cloudy days. It is also largely maintenance-free and requires no launch or recovery. These can be powerful units, churning out 400 watts of power or more—enough to charge 800 amp hours (Ah) of battery capacity per day on a 12-volt system.

On the down side, the world’s cruising routes tend to be downwind, robbing the generator of some of its power. In fact, the relationship between wind speed and the energy it contains is cubic, so power decreases exponentially. To put that in context, a boat doing 8 knots dead downwind in 20 knots of true wind would experience an apparent wind of just 12 knots. A turbine might generate 40 watts in 12 knots of wind, but most manage 200