What should the DPO's first action be if a bow tunnel thruster fails to full force during DP operation on a Class 2 vessel?

In the event of a bow tunnel thruster failing to full force during Dynamic Positioning (DP) operations on a Class 2 vessel, the first action of the Dynamic Positioning Operator (DPO) should indeed be to deselect the failed thruster from the DP Operator Station. This step is crucial for maintaining control of the vessel and ensuring the DP system can operate effectively with the remaining thrusters.

By deselecting the failed thruster, the DP system can adjust its calculations and control strategies based on the available thrust. This action allows the DP to reconfigure itself and mitigate the impact of the thruster failure, thus enhancing the vessel's ability to maintain its position and heading.

Taking this action also helps to prevent the DP system from attempting to compensate for the lost thrust from the failed unit, which could lead to instability or an unwanted drift. Moreover, it signals to the system that it should not rely on the failed equipment, ensuring that the DPO's commands are based on the operational capabilities of the remaining thrusters.

The other actions suggested would not be as effective in addressing the immediate issue presented by the thruster failure. Options involving manual control or increasing speed could introduce additional risks, especially in terms of vessel stability and control, while