Under what scenario should DP capability plots be recalculated?

Recalculating DP capability plots is essential whenever there is a change in the configuration of the Dynamic Positioning (DP) system that could impact its performance, and one of the most critical factors is the location of the antennas, which affects the offsets used in the DP system.

When the antenna location changes, it alters how the system calculates and maintains position due to variations in signal reception and transmission. This change may lead to different accuracy levels in environmental conditions affecting controllability and position holding capability. Therefore, it is crucial to recalibrate DP capability plots in this scenario to ensure that the system can still meet operational requirements with the new configurations.

In contrast, recalculating plots just once a year during inspections, only after reported malfunctions, or even after equipment maintenance, may not adequately address the immediate adjustments necessary for the performance and safety of the vessel in dynamic positioning operations. Antenna location changes are significant enough to warrant immediate recalibration to ensure safe and efficient DP operations.