Btw, I have solar electric auxillary propulsion on my sailboat

I have no issues with electric propulsion.
My thought is that a traditional 70 ft schooner may have too small of a cargo capacity to be profitable.
Consider crewing costs. For a cargo vessel to be competitive on long range transport, ideally it would be carrying, loading or discharging cargo 24/7 or close to it. Say you can get away with 6 crew per rotation. $500 000/ year in crewing costs. Times 2, because most sailors are looking to work time on for time off these days. That puts your crewing costs at a million dollars a year? Give or take a few hundred thousand?
Say the buisiness is delivering supplies to island out stations in Alaska and BC (I see you posted this in the BC/ Alaska sub forum), you could probably get away with daylight only operations and only a single crew, but that still leaves you competing with small fast power boats carrying similar volumes with one or two crew at 2-4 times the speed