Re: Alternative to Solar
In order to understand the market needs one would need to first define the market. If that is recreational sail (not power) boaters, have your friends yet found out how many boats in each size range there are? How many existing, how many added each year?
Then since the "box" can't be a miracle, one would need to define the size, weight, and output of "the box" or a range of boxes, to ask the boaters if that device would be of any interest to them.
Tell me a shoebox that weighs 20 kilos will reliably give me 50AH at 14 volts over the course of 24 hours at anchor in a calm anchorage and I will be interested. Tell me it will be four times the size, twice the weight, and product only 10AH at 14V over the course of 24 hours in rough water, and I won't be interested.
But unless I missed something so far you are only asking "Would you like a box that makes electricity?" and I was promised that around 1960. They promised us home nuclear generators, each the size of a home hot water heater (about 2' in diameter and 5' tall) that would provide all the power a hungry American single-family home would need.
I'm still waiting.