USVs

 USV stands for unmanned surface vehicle, which is a boat or ship that operates on the water's surface without a human crew. USVs can be remotely controlled by a human operator or programmed to perform missions autonomously. They are also known as drone boats, drone ships, or sea drones. 

 AUV stands for autonomous underwater vehicle, which is a robotic, unmanned, and untethered vehicle that can conduct underwater research and surveys without human intervention. AUVs are used by the military, ocean scientists, and the marine industry