Pretty self-explanatory news article from AP. A couple of c & p paragraphs from it.
BOSTON (AP) — Self-driving cars may not hit the road in earnest for many years - but autonomous boats could be just around the pier.
Spurred in part by the car industry's race to build driverless vehicles, marine innovators are building automated ferry boats for Amsterdam canals, cargo ships that can steer themselves through Norwegian fjords and remote-controlled ships to carry containers across the Atlantic and Pacific. The first such autonomous ships could be in operation within three years.
One experimental workboat spent this summer dodging tall ships and tankers in Boston Harbor, outfitted with sensors and self-navigating software and emblazoned with the words "UNMANNED VESSEL" across its aluminum hull.
"We're in full autonomy now," said Jeff Gawrys, a marine technician for Boston startup Sea Machines Robotics, sitting at the helm as the boat floated through a harbor channel.
"Roger that," said computer scientist Mohamed Saad Ibn Seddik, as he helped to guide the ship from his laptop on a nearby dock.
The boat still needs human oversight. But some of the world's biggest maritime firms have committed to designing ships that won't need any captains or crews — at least not on board.
Me here: I distinctly recall having a conversation with a recent graduate of US Naval Academy back in the 60's. He happened to mention that some shipping vessels were equipped with what he referred to as "Iron Mike", an airplane type autopilot--basically steering chores. He also commented, in general terms, that in the US Navy the 'word on the street' was that US Navy vessels should always presume that the entire crew of cargo type vessels was asleep especially during night watches.
Thing is, even is something got in the way, I'm not sure what you could do about it on a large ship. So why not?