Ro-Boat

Amsterdam have been recently testing out robot controlled boats among other self navigating vessels

Image via swzmaritime.nl

Some of the these autonomous boats are more friendly than others such as the ones the navy has.

Image via nbcnews.com

The best use for any autonomous vehicle is public transport. They can be placed on planned controlled routes and be visibly labeled so that people can identify them. Other utility uses will be good too, although the military sounds a bit scary.