Repair and Maintenance of Bow Thrusters

Bow Thrusters 

Bow thrusters are a type of propeller-shaped system fitted either on the bow (forward) and stern part of the ship. They are generally used for manoeuvring the ship near the coastal waters, channels or when entering or leaving a port while experiencing bad currents or adverse winds.

The requirement for the number of thrusters to be installed depends on the length and the 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 bow and the stern thrusters can be electrically driven or hydraulic driven or diesel driven. However, the most commonly used are electric driven, as in hydraulic driven thrusters there occur many leakage problems.

Also, with diesel-driven bow thrusters, the amount of maintenance required is more and every time before starting someone needs to go to the thruster room to check the thrusters. The boss which carries the blades is internally provided with a movable shaft (operated by hydraulic oil) also know and Hydraulic Pod Motor-driven Thrusters. Once the signal is given to change the pitch, the hydraulic oil will be supplied to operate the internal shaft (within the boss) to change the blade angle of the thruster

Function of Bow-Thrusters

Bow thruster consists of an electric motor which is mounted directly over the thruster using a worm gear arrangement. The motor runs at a constant speed, and whenever there is a change required in the thrust or direction, the controllable pitch blades are adjusted. These blades are moved, and the pitch is changed with the help of hydraulic oil which moves the hub on which the blades are mounted. As the thruster is of controllable pitch type, it can be run continuously, and when no thrust is required, the pitch can be made to zero.

Bow Thrusters Underwater Maintenance

• Checking the bow thruster compartment for any water leak which may eventually lead to rusting.
• Cleaning the power supply unit and inspection for corrosion in engine
• Bow thruster shaft test for cracks and propeller control for cracks or knocks or cavitation.
• Cleaning of the marine fouling/ growth inside the tunnels and propeller