Which statement about emergency power supply is accurate?

• A. An emergency generator must power only the navigation equipment.
• B. An emergency power supply is optional if the main power remains available.
• C. It must provide power to essential services when main power fails, and be tested.
• D. It should be replaced by a battery bank within 24 hours.

Answer: (C)

The key idea is that the emergency power supply is there to keep essential services operating if the main electrical system fails, and it must be checked regularly to ensure it works when needed. This backup should automatically step in to power critical systems—like navigation, communications, safety equipment, and emergency lighting—so the ship can operate safely during a power loss. It’s not limited to just navigation gear, and it’s not optional just because the main power is currently available. It also isn’t something that should be replaced by a battery bank within a fixed short timeframe; the emphasis is on providing reliable power to essential services for a defined period and on regular testing to verify reliability.