Abstract
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 language | English |
|---|---|
| Title of host publication | Proceedings of the 26th International Ocean and Polar Engineering Conference |
| Subtitle of host publication | ISOPE 2016 |
| Editors | A.M. Wang, J.S. Chung, T. Kokkins, M. Muskulus |
| Publisher | International Society of Offshore and Polar Engineers (ISOPE) |
| Pages | 1602-1608 |
| ISBN (Print) | 978-1-880653-88-3 |
| Publication status | Published - 2016 |
| Event | 26th Annual International Ocean and Polar Engineering Conference, ISOPE 2016 - Rhodes, Greece Duration: 26 Jun 2016 → 1 Jul 2016 |
Conference
| Conference | 26th Annual International Ocean and Polar Engineering Conference, ISOPE 2016 |
|---|---|
| Country/Territory | Greece |
| City | Rhodes |
| Period | 26/06/16 → 1/07/16 |
Keywords
- dynamic positioning
- capability plot
- time domain simulation
- mean environmental force
- DP offset
- semi-submersible
- drillship
- wave drift
