Cruising the Chesapeake and its many tributaries is one of life’s great pastimes. Whatever motivates us to seek out a quiet harbor will also require us to evaluate the DC power system on our boat. Stored energy in our batteries can only support our equipment and creature comforts for so long before they need recharging, which requires us to start a generator to power the battery charger, or run the main engine for the alternator to do its work. But, there are other choices. An alternative green energy system can reduce the recharging times required and even extend the life of our batteries.  Hydro-generators can be very efficient for sailors on long passages. These involve trailing a propeller through the water attached to a generator, which produces electrical power while sailing.  However due to the very high initial cost, a Bay cruiser (even one that makes an occasional Bermuda, or coastal trip) would be hard-pressed to justify the payback. These devices only work when underway. So, in our serene anchor-out example, they are of no benefit. Wind generators are wind turbines mounted on poles high enough that you should not be able to reach up and touch the blades. As the wind v...