Unlike a more conventional system where diesel engines drive one or more propellers, QM2 features pods mounted externally on each side of the vessel. Each pod contains an electric motor, driven by a generator from he ship’s diesel engines and connected via shaft to a fixed pitch propeller.

Two of the pods are static and two rotate through 360(DEGREES), combining to produce speeds above 30 knots yet producing lower levels of noise and vibration throughout the vessel and better fuel efficiency than a conventional propulsion system. The pods also eliminate the need for rudders and stern thrusters, providing greater manoeuvrability than has previously been possible for a vessel of this size.

For the ship’s operators, the Cunard Line, it is essential to maximise the operating life of QM2 and minimise the time it is unavailable due to maintenance and repair. The ship’s engineers have thus incorporated sophisticated condition monitoring technology in he pods, based around SKF’s MasCon48 system.

MasCon48 measures the level and pattern of vibration from the various shafts and bearings used in each pod, plus the temperature of motor windings and bearings, and the quality and changing condition of lubricating oils, using sensors and particle counters mounted in each oil sump. The system relays data and any anomalies to maintenance personnel on board, together with advice for correcting existing or impending conditions.

The data is also simultaneously relayed via a satellite to both the SKF Condition Monitoring Centre and the Rolls-Royce Control Centre in Sweden. Alarms are presented as plain text messages to maintenance crews highlighting problems such as unbalanced shafts, cavitation, bearing condition or electrical faults.

The MasCon48 system was especially modified to meet the demands of the QM2 operating environment. In particular, special rule based diagnostics were incorporated to prevent false alarms being generated during complicated ship manoeuvres, which can create unusual vibration patterns that vary from normal cruising conditions and can take time to settle. The diagnostics re therefore set to monitor ship speed, shaft speed and steering angle and to compare this data with standard readings before deciding when to resume normal monitoring conditions.