Azipod

Closeup of one of USCGC Mackinaw's azipods

Azipod is the registered brand name of the ABB Group for their azimuth thruster. Originally developed in Finland jointly by Kvaerner Masa-Yards dockyards and ABB, these are marine propulsion units consisting of electrically driven propellers mounted on a steerable pod.

The pod's propeller usually faces forward because in this puller (or tractor) configuration the propeller is more efficient due to operation in undisturbed flow. Because it can rotate around its mount axis, the pod can apply its thrust in any direction. Azimuth thrusters allow ships to be more maneuverable and enable them to travel backward nearly as efficiently as they can travel forward.

The new CRP (Contra-Rotating Propeller) Azipod places a contra-rotating azipod propeller behind a fixed propeller achieving improved fuel efficiency.^[1]

Azipod concept

In the traditional azimuth propulsion system the motor is inside the ship's hull and the propeller is driven through shafts and gearboxes. In the Azipod system the electric motor is inside the pod, and the propeller is connected directly to the motor shaft. By avoiding the use of a traditional propeller shaft, the propeller can be further below the stern of the ship in a clear flow of water providing greater hydrodynamic and mechanical efficiency.

Electric power for the Azipod motor is conducted through slip rings that allow the Azipod to rotate through 360 degrees. Because fixed pitch propellers are used in Azipods, power for an Azipod system is always fed through a variable-frequency drive or cycloconverter that allows speed and direction control of the propulsion motors.

See also

• A similar competing product is the Rolls-Royce Mermaid azimuth thruster.^[2][3] This is the thruster on the Queen Mary 2.
• Finnish Maritime Cluster
• L-drive
• Voith Schneider Propeller
• Z-drive

Notes

External links

• The CRP Azipod Propulsion Concept Maritime Suppliers
• Article about use of azipod in semisubmersible rig