What happens to Class 2 Dynamic Positioning operations if one azimuth thruster is out of service?

In Class 2 Dynamic Positioning operations, the system is designed with a certain level of redundancy to ensure reliability. A Class 2 DP system indicates that the vessel is capable of maintaining its position and heading even in the event of one failure in the dynamic positioning system components.

When one azimuth thruster becomes inoperative, the redundancy that Class 2 provides is compromised. In this scenario, the vessel does not meet the operational requirements of Class 2 anymore since it relies on all its thrusters to safely and reliably maintain position during operations that demand this classification. As a result, operations that require the vessel to adhere to Class 2 standards would not be permitted, as this classification is contingent on having all systems functioning properly.

Continuing operations under these circumstances would not be safe, nor appropriate, as the remaining thrusters may not provide adequate control in all situations, particularly in adverse conditions or where precise positioning is critical. Hence, without the full complement of operational thrusters, the safety and operational integrity cannot be guaranteed.