The first of two $1.5 billion 27,000-tonne Landing Helicopter Docks (LHDs), to be known as HMAS Canberra, suffered excessive vibration in May during her first “shakedown cruise” between Melbourne and Sydney.
The fault was traced to the brand-new vessel’s two German-built Siemens propulsion pods — or azimuth thrusters — which were out of alignment.
Each thruster, fitted at the stern of the ship, has two propellers mounted on large electric powered pods that can be rotated to any angle, eliminating the need for a rudder. And just like the wheels of a car, poor pod alignment causes vibration.
A crew from Teekay Shipping Corporation was hired by prime contractor BAE Systems and was apparently unaware that the pods must be operated in tandem above eight knots.
They ran them independently in low-speed mode at high speed, causing serious vibration throughout the ship.