Under which condition is Cruising Condition III used?

Cruising Condition III is utilized during international waters with potential hostile encounters. This condition is specifically designed to enhance a ship's readiness and responsiveness in scenarios where there is a possibility of engagement or threat from adversaries. When a vessel is in this condition, it is prepared for immediate action while still maintaining operational capability.

Under Cruising Condition III, essential systems are operational, and watch teams are heightened, ensuring that the crew is ready to react to any form of threats that may arise. This proactive readiness is critical in international waters where encounters with hostile forces may occur, thus safeguarding the ship and its mission.

The other conditions in the options provided do not align with the intent and operational posture of Cruising Condition III. For example, being in port during maintenance typically indicates a lower level of readiness, while exercises in safe environments and peacetime operations generally do not require the heightened state of awareness and readiness that Cruising Condition III entails.