Queen Mary 2: CCL Photo Atrributed to 'Clicgauche' Cunard cruise ship Queen Mary 2 suddenly lost power to all four propulsion pods for about an hour due to an engine room explosion as she neared Barcelona in the early hours of an Autumn morning last year. Fortunately nobody was hurt, but last week the U.K Marine Accident Investigation Branch (MAIB) issued a meticulous technical report on the accident, granting that, ‘Losing control of a large cruise liner due to an electrical blackout, with 3,823 people on board, is a serious concern.’ A short account of what went wrong follows.Cause of the ExplosionBackground is that the QM 2's CODLAG (Combined Diesel Electric And Gas Turbine) propulsion system with its variable speed AC electric motors constitute a major source of harmonic distortion to electricity supply (the change in the waveform of the supply voltage from the ideal sinusoidal wave-form) which unless corrected has a deleterious effect on other electrical components in... [More]