When I go out on my boat into saltwater I pass many marinas that have sailboats and have noticed that many of them today have a wind turbine. These turbines generate power for the boat from the wind for free outside the inital investment of about $1000. These turbines are virtually silent depending on the model and can generate enough power to charge the batteries even when sitting still. With the turbine you could be offshore as long as you want given your food and water holds out and have enough power to crank your outboard, run the radio, coffee maker and other appliances on board without worrying about your battery life. What a great invention.