Optimal thruster location on offshore DP vessels

During the design process of an offshore vessel, the DP system is not representing one of the primary constraints for the general arrangement of the vessel. Usually the location of the thruster devices is driven by the internal spaces available, i.e. the thrusters position is not optimised to reach the maximum capability. This is also true for a conversion of an existing vessel. Nowadays almost all offshore vessels require the installation of a DP system on board, means that it could be worthy to study more in detail the arrangement of the thrusters in such a way to maximise the capability of the vessel to keep position with a determined amount of power installed on board. In the present work a procedure aimed to find an optimal thruster location on the hull during early design stage will be presented. Using a quasi-static approach for DP capability evaluation, an optimisation procedure based on genetic algorithm has been developed, considering the constraints given by the vessel geometry. The discussion is supported by a test case on a reference vessel, were the original layout is compared with two possible optimised configurations.