Great idea! Would be good if it got a little lower and closer to the person before dropping the life saver. Many people in the process of drowning don’t have the strength or ability to swim even a few feet.
Another improvement would be to have it hover above the beach area at all times. Linked to a video watched by the lifeguard, it could help the lifeguard identify swimmers at risk, and make it easier for him to pilot the drone to the victim.
It may even be possible for the drone/video station to monitor all the swimmers in the area and identify swimmers beginning to drown. There are certain behaviors they typically exhibit.
Fine for somebody caught in a riptide. I have seen a guy in the process of drowning before. He couldn’t swim that far.