An underwater thruster is a configuration of marine propellers and hydraulic or electric motor built into or mounted to an underwater robot as a propulsion device. These give the robot movement and maneuverability against sea water resistance. The main difference between underwater thrusters and marine thrusters is the ability to work under heavy water pressure, sometime up to full ocean depth.
BlueROV2 with electric thrusters
Copenhagen Subsea 10-15kW electric underwater thruster
A Lian Innovations electric thruster
Autonomous underwater vehicle
An autonomous underwater vehicle (AUV) is a robot that travels underwater without requiring continuous input from an operator. AUVs constitute part of a larger group of undersea systems known as unmanned underwater vehicles, a classification that includes non-autonomous remotely operated underwater vehicles (ROVs) – controlled and powered from the surface by an operator/pilot via an umbilical or using remote control. In military applications an AUV is more often referred to as an unmanned undersea vehicle (UUV). Underwater gliders are a subclass of AUVs.
Picture taken of the Battlespace Preparation Autonomous Underwater Vehicle (BPAUV) by an employee of Bluefin Robotics Corporation during a US Navy exercise
The Blackghost AUV is designed to undertake an underwater assault course autonomously with no outside control.
Pluto Plus AUV for underwater mine identification and destruction. From Norwegian minehunter KNM Hinnøy
A University of South Florida researcher deploys Tavros02, a solar-powered "tweeting" AUV (SAUV).