Analysis on DP performance of a shuttle tanker with various analysis methods

Abstract

The present investigation demonstrates that the estimation of dynamic effects should be included carefully in the analysis of DP performance through model test or dynamic analysis tool where dynamic effect model is included. There are three widely used analysis methods for design and evaluation of DP performance. Dynamic analysis with time domain simulation, static analysis based on mean environmental forces, and model test can be used to analyze the holding capacity of a designed DP system. Among the three analysis methods, the static analysis is most widely used in the design stage. In this paper, heading windows of a 145 K shuttle tanker as a holding capacity are evaluated using these three methods. Those three results are compared with each other to investigate reliability of state of the art method. The estimated heading window shows differences depending on analysis methods. The difference was most significant in ballast loading condition, this could be from larger thruster degradation effects. The feasibility of 20% margin in static analysis for dynamic effects was confirmed in some conditions, but some results shows larger dynamic effects in model test.