Norwegian Cruise Line is to install the new Rolls-Royce permanent magnet tunnel thruster onboard Norwegian Epic to upgrade the ship’s current propulsion package.
Rolls-Royce’s permanent magnet tunnel thruster offers numerous advantages over traditional tunnel thrusters including significant reduction in noise and vibration, as well as a 25% increase in power output from the same size propeller. The thruster is capable of running for thousands of hours in intensive dynamic positioning mode and can also be removed underwater, which eliminates the need for drydocking.
Other benefits of permanent magnet technology include the freeing up of space directly above the thruster where traditional tunnel thruster motors are located, and a symmetrical design that gives equal thrust to port or starboard. It is available in 1600mm and 2000mm diameter.
“We are delighted that Norwegian is the first cruise customer to select our new permanent magnet tunnel thruster as an upgrade to an existing propulsion package,” said Jay McFadyen, senior vice president of Marine Services, Americas at Rolls-Royce. “Passenger comfort is a top priority for cruise lines, and the reduction of both noise and vibration, which our permanent magnet technology provides, is of paramount importance to successful cruise operators like Norwegian.”
The thruster comprises a permanent magnet motor in a rim, which drives the propeller in the centre. The permanent magnet motor consists of two main parts – a stator that carries a number of electrical coil windings, and a rotor fitted with a number of very strong permanent magnets. A rotating magnetic field is created by the stator, which interacts with the fields of the permanent magnets on the rotor, generating force to drag the rotor around and provide the mechanical power.