Looks pretty stealth. Navigation hazard?
Not to any vessel of substantial mass it isn't.
Yes, interesting, but what is the purpose? I see no gain since most ships/boats use autopilot of some type. And, what if the host system crashes? Now we have a piece of sea junk. Just like if a satellite loses control it becomes a piece of space junk.
Maybe I can see a military application if the vessel is small and as you say, stealth.
Also, Robert Redford can make a follow on movie about his sailboat hitting a sailing drone and sinking both. :naughty::dance: