14. starptautiskā konference 2012 - Latvijas Jūras akadēmija

Proceedings of 14th International conference „Maritime Transport and Infrastructure - 2012”Fig. 2. Example of AE readings2. AE applicationHaving relayed the theoretical concept of the AE system, we would like to further provide anumber of real-life cases as examples of situations where the application of the AE technologies fordamage detection would have prevented significant ship`s damage and consequential financial loss.However, for commercial privacy reasons we cannot disclose any names or provide any facts servingto identify the vessels and the parties involved. Furthermore, some minor details, not related to theactual topic of the paper, were changed for the same reason.As a first example we would like to take a 4000TEU middle size containership, loaded up toabout a half of her capacity with full containers, which suffered a sudden and unexpected crack in thecrankshaft, resulting in heavy damage to the main bearing, and the breakdown of the engine. As inmany similar cases, the problem was identified by noticing a rise of the temperature. While this servedas a good alarm to prevent any further damage, it was actually a result of a damage which had alreadyhappened and, quite logically could not be prevented anymore. The main engine was immediatelystopped in order to limit the damage, but AE would have allowed for an earlier warning, perhapsallowing preventing the breakdown at all.As a result of the incident, the vessel has to be towed to the nearest port of refuge, where thefull containers had to be transhipped on other vessels for further on-carriage to the correspondingconsignees, arriving with significant delays. The vessel itself was put in lay-up for lengthy and costlyrepairs – replacement of the crankshaft and the bearing - thus bringing her out of service for a periodfor about half a year. Due to obvious reasons, we cannot disclose the exact figures, but we can advisethat the repairs alone will cost over two and half a million Euros. In addition, one has to take intoaccount the extra logistical costs for the transhipment and on-carriage operations, compensations forcargo consignees for late deliveries, vessel being out of service for an extensive period of time,surveyors and supervision costs and so on. The overall costs involved can easily be estimated to reachan astonishing amount of three and a half million Euros.Currently the exact reason for the breakdown was still not yet certainly identified, but issuspected to be related to the bending forces affecting the crankshaft, originating from the cargoloading and distribution on-board throughout many years of the vessel`s operations. Which means thatif the AE system would have been applied, it would allow identifying the problem a lot earlier andpreventing the breakdown by applying the necessary preventive measures/amendments in due time -ranging from revision of cargo distribution patterns and up to replacement of the crankshaft. Needlessto say, if applied in correct time these measures would have brought the overall costs down quitesignificantly. Furthermore, it would allow for similar measures to be applied to the vessel`s sisterships,which are now feared to soon start encountering similar problems.115