What should a DPO do immediately if a non-connected thruster fails to full force?

When a non-connected thruster fails to full force, the immediate action a Dynamic Positioning Operator (DPO) should take is to deselect the failed thruster from the DP Operator Station. This action is crucial because it prevents the dynamic positioning system from attempting to utilize the compromised thruster, which can lead to instability in maintaining the vessel’s position. By deselecting the failed thruster, the DPO ensures that the rest of the thrusters can continue to operate effectively and maintain the required DP control, thereby safeguarding operations and the vessel's integrity.

In the context of vessel operations, activating a backup thruster may not be the immediate priority, especially if the current thrusters can still manage the position. Increasing power to the failing thruster could potentially cause more issues, as it may lead to further complications if the thruster is already not functioning correctly. Continuing with operations as planned without acknowledging the failure could result in significant safety hazards, as the vessel might not maintain its position effectively. Therefore, deselecting the failed thruster from the system is the most appropriate and immediate action to maintain control and safety.