Unmanned underwater vehicles (UUV), sometimes known as underwater drones, are submersible vehicles that can operate underwater without a human occupant. These vehicles may be divided into two categories: remotely operated underwater vehicles (ROUVs) and autonomous underwater vehicles (AUVs). ROUVs are remotely controlled by a human operator. AUVs are automated and operate independently of direct human input. Classifications Remotely operated underwater vehicle Remotely Operated Underwater Vehicles (ROUVs) is a subclass of UUVs with the primary purpose of replacing humans for underwater tasks due to the difficult underwater conditions. ROUVs are designed to perform educational or industrial missions. They are manually controlled by an operator to perform tasks that include surveillance and patrolling. The structure of ROUVs disqualify it from being able to operate autonomously. In addition to a camera, actuators, and sensors, ROUVs often include a “gripper” or something to grasp objects with. This may throw off the weight distribution of the vehicle, requiring manual assistance at all times. Sometimes ROUVs require additional assistance due to the importance of the task being performed. The US Navy developed a Submarine Rescue Diving Recompression System (SRDRS) that can save up to 16 people up to 2000 feet underwater at a time. Such a large vehicle with the primary role of saving lives requires an operator(s) to be present during its mission. Autonomous underwater vehicle Autonomous Underwater Vehicles (AUVs) are defined as underwater vehicles that can operate without a human operator. Sizes can range from just a few kilograms up to thousands of kilograms. The first AUV was created in 1957 with the purpose of performing research in the Arctic Waters for the Applied Ph Laboratory at the University of Washington. By the early 2000s, 10 different AUV had been developed such as screw driven AUVs, underwater gliders, and Bionic AUVs. The earliest models used screw propeller thrusters while more recent models utilized automatic buoyancy control. The earliest model, SPURV, weighed 484 kg, went as deep as 3650 meters, and could travel for up to 5.5 hours. One of the most recent models, Deepglider, weighs 62 kg, can go as deep as 6000 meters, and can travel up to 8500 km. History 1950s Starting in 1957, the first unmanned underwater vehicle (UUV) was classified as an autonomous underwater vehicle (AUV), and was created in the United States to research the Arctic waters. The Special Purpose Underwater Research Vehicle (SPURV), was used by the University