Bow and Stern Thrusters, also known as the side thrusters, are transverse thrusters placed in a duct located at the forward and aft end of the ship. The thruster set in the forward end is known as the bow thruster and the one placed in the aft end is known as the stern thruster. The bow thruster working and the requirement for the number of thrusters to be installed depends on the length and the cargo capacity of the ship. The route of the vessel also plays an important factor as many countries have local regulations of compulsory use of tugboats to enter or leave their port limits. The thrusters are usually of controllable pitch blade types.
The bow and stern thrusters are placed in the through-and-through tunnels which open at both sides of the ship. There are two such tunnels – at forward and aft ends of the ship. The thruster takes suction from one side and throws it out at the other side of the vessel, thus moving the ship in the opposite direction. This can be operated in both the directions, i.e. port to starboard and starboard to port. The bow thrusters are placed below the water line of the ship. For this reason, the bow thruster room should be checked for water accumulation at regular intervals of time.
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