Offset requirements in quasi static DP capability calculations

Wouter Antheunisse, Dimitris Chalkias, Rene Huijsmans

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

3 Citations (Scopus)


The Dynamic Positioning (DP) performance of a ship or semi-submersible is often expressed in a polar plot called a DP capability plot. In an early design stage the DP capability plot is calculated by the so called quasi-static calculation method. A drawback of the method is that it cannot predict the vessel offsets from the mean position in a given environment. In this paper a novel approach to calculate DP capability in an early design stage is presented. Based on the traditional concept of Dynamic Margin, the quasi-static calculation method is extended in order to account for the time variable environmental forces and offset requirements. Force Multiplication Factors (FMFs) dependent on specific DP-offset requirements are introduced to replace the fixed Dynamic Margin. Through time domain simulations, it is shown that a good correlation exists between such FMFs and the extremes of the excitation force impulse peaks. FMFs are calculated for a semi-submersible and a drillship.
Original languageEnglish
Title of host publicationProceedings of the 26th International Ocean and Polar Engineering Conference
Subtitle of host publicationISOPE 2016
EditorsA.M. Wang, J.S. Chung, T. Kokkins, M. Muskulus
PublisherInternational Society of Offshore and Polar Engineers (ISOPE)
ISBN (Print)978-1-880653-88-3
Publication statusPublished - 2016
Event26th Annual International Ocean and Polar Engineering Conference, ISOPE 2016 - Rhodes, Greece
Duration: 26 Jun 20161 Jul 2016


Conference26th Annual International Ocean and Polar Engineering Conference, ISOPE 2016


  • dynamic positioning
  • capability plot
  • time domain simulation
  • mean environmental force
  • DP offset
  • semi-submersible
  • drillship
  • wave drift


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