Greetings. This is my first post and my first venture into hydroelectric power. I'm wondering if there is a mini or micro Turbine available (that works) that could be hung off a small sail boat (Hobie Island) to maintain the 12v battery used for a chartplotter which draws 0.6aH. I'm just getting into sailing and heard that some people use solar panels for this purpose, but seems like a possibility for a turbine as well. Thoughts, suggestions? Thanks.