And not just that, now you have to have a way to put all that energy back into the batteries each day. This is hard to do from solar or wind alone if you need a

And not just that, now you have to have a way to put all that energy back into the batteries each day. This is hard to do from solar or wind alone if you need any sort of real-world range (20-30nm/day for instance). It may be Ok for a day sailor that just uses an engine to get in and out of the harbor but if you use your boat to do real travel you can't always rely on wind for sailing or a dock to plug into at night. For instance, in a typical Pacific Northwest summer even a sailboat ends up motoring a lot in the Inside Passage with few places to recharge from plug-in electricity. Some hybrid systems that use a diesel generator and lithium batteries almost get there but it's tough to make it all fit in a sailboat in the 35ft range, which is a popular size. Diesel is a pretty compact energy storage system for boats and it's hard to beat. We recently had to repower our sailboat and we just couldn't make it work without severely limiting our range.