Fishing trawler Vellee sank in the Little Minch channel west of Scotland’s Isle of Skye on a calm and clear night last summer apparently without being holed, leading MAIB (UK Marine Investigation Branch) investigators to conclude in their recent accident report that the loss probably resulted from a catastrophic failure of internal sea water piping or fittings – most probably the outcome of advanced electrolytic corrosion.
Fishing Trawler Vellee: Photo courtesy of Skipper JimmyT
Evidence of Corrosion as Probable Cause
A few days before the trawler’s final voyage (from Fraserburgh north-about mainland Scotland to Kilkeel on the east coast of Ireland for better fishing in the Irish Sea) repairs to the main engine were needed, and engineers discovered that two of the eight cylinder liners of the main Kelvin TASC8 engine were badly corroded by electrolytic action; thickness reduced by as much as 85% in some places. An electrician called to investigate, thought that ... [More]
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]