DP Thrusters - Understanding Dynamic Loads and Preventing Mechanical Damages

AuthorsDang, J.
Conference/JournalDynamic Positioning Conference
DateOct 20, 2014

Despite the wide and successful use of mechanical azimuthing thrusters in various marine applications,such as dynamic positioning (DP), dynamic tracking (DT), bollard pull (BP), low speed manoeuvring, aswell as high speed transit trips at continuous full power (then used as the ship's main propulsion system),damages on the gears and bearings of mechanical azimuthing thrusters have been reported in many cases.According to the statistics of survey records of major classification societies (e.g. ABS, DNV and LRS),the failures of gears and bearings are among the first three major kinds of damages, where one of them isthe propellers which are however exposed directly to a quite harsh environment in the water.In order to help the industry to get an insight in the failures with respect to the external loads on the drivesof thrusters, MARIN has been dedicated in studying the hydrodynamic loads on mechanical azimuthingthrusters in the past decades. Series of six-component transducers, with high-accuracy and high responsefrequencies, have been designed, manufactured and applied. Systematic model test campaigns and fullscalemeasurements in order to obtain dynamic loads to the higher frequencies have been carried out.Through investigations into extreme manoeuvring ope