Startup company Hydronalix
from Arizona has developed an autonomous robot lifeguard. The robot consists of a flotation device attached to an electric impeller, which drives it at speeds of up to 45 km/h. A remote controlled version of the robot lifeguard is currently used to patrol Malibu’s dangerous Zuma Beach, where 25 additional robot lifeguards will follow by December.
The autonomous version of the robot uses sonar to home in on the underwater movements associated with a swimmer in distress. It will go on sale next spring for 2800 Euros or 3500 USD.
More info on Popular Science