The market is very small for hydro generators for sailboats.
Solar is much cheaper because you can buy products that are targeted at mass market instead of only at sailboats.
Source: I was recently purchased by a sailboat.
And what does your sailboat intend to do with its new purchase?
The two happiest days of a boat owner's life: the day they buy the boat, and the day they sell the boat.
The market is very small for hydro generators for sailboats.
Solar is much cheaper because you can buy products that are targeted at mass market instead of only at sailboats.
Source: I was recently purchased by a sailboat.