How is a casualty alarm sounded during an emergency situation?

The correct method for sounding a casualty alarm during an emergency situation is indeed achieved by using a rapid bell followed by bells specific to the zone number. This approach is specifically designed to alert crew members to the nature of the emergency and its location on the vessel.

Using a bell system provides a clear and distinct signal that can be easily recognized and interpreted by trained personnel, allowing them to respond appropriately. The rapid bell conveys urgency, while the zone bells inform the crew of the specific area affected, which is critical for efficient and targeted responses.

In contrast, other methods like using a single horn blast or broadcasting over the intercom may not convey the necessary level of urgency or specificity required in a casualty situation. A loudspeaker announcement may not be as effective in noisy environments or in situations where quick identification of the alarm’s nature and location is essential, potentially leading to confusion or delays in response. Thus, the method involving a rapid bell and designated zone bells is the most effective for effective communication during emergencies.