According to IMO MSC/Circ. 654 of 1994, how long should an Uninterruptible Power Supply UPS battery system power the DP computer system after a mains failure?

The correct answer is that the Uninterruptible Power Supply (UPS) battery system should provide power to the Dynamic Positioning (DP) computer system for a minimum of 30 minutes after a mains failure, as stipulated by IMO MSC/Circ. 654 of 1994. This 30-minute duration is crucial, as it allows sufficient time for the crew to take appropriate actions in the event of a power failure. These actions could include transitioning to backup systems or safely shutting down operations to avoid risks to the vessel and personnel.

This requirement ensures that the DP system can maintain its operational integrity long enough for the necessary safety protocols to be executed, preventing potential accidents or loss of control in critical marine operations. The duration of 30 minutes strikes a balance between providing a reasonable timeframe for response without unnecessarily extending battery requirements, which could lead to increased costs and complexity in the power supply system design.

The other options would not meet the regulatory and safety needs outlined by the IMO, making the 30 minutes the most relevant and necessary guideline for ensuring the safety and reliability of DP operations.