The Gulf Stream is like a tide pushing a boat south on the west coast.
Going uphill back north is a major task, sailboats often sail northwest and then north east to avoid going against it.
Are you not getting the idea here..A crewless cargo boat needs nothing but steerage and some motive power and communications electronics, it is a one-trip boat that just needs to float and steer. Plenty of cheap boats that float and steer but are inhabitable.
Now of course this is not a simple easy project, it would need plenty of testing to make sure it would work, and certainly if your only goal is moving your stuff, easier ways to do it. Doing the impossible is just something that hasn't been done yet.
BTW, I built the worlds first electric powered jetski.
They have autonomous sailboats already, just not carrying cargo.
https://www.digitaltrends.com/cool-t...sses-atlantic/