Boat thrusters are auxiliary propulsion systems used to provide additional manoeuvrability to boats and yachts, especially at low speeds or in tight spaces where traditional propulsion systems may be less effective. They work by generating lateral thrust to move the boat sideways, forward, or backward without the need for forward motion from the main engines. 

• Bow Thrusters: These are mounted in the bow (front) of the boat and provide lateral thrust to aid in docking and maneuvering in tight quarters. They're particularly useful for counteracting wind and currents when docking.
• Stern Thrusters: Mounted in the stern (rear) of the boat, stern thrusters provide lateral thrust in the opposite direction of bow thrusters. They're often used in combination with bow thrusters to improve overall maneuverability.