Muster drill

[1] It is typically conducted approximately 30 minutes prior to the ship's scheduled departure time, and all guests must remain silent during the drill so that everyone will be able to hear the safety announcements from the captain.

As required by the International Convention for the Safety of Life at Sea, a passenger muster drill must be conducted by the ship within 24 hours of departure.

[2] However, in the wake of the Costa Concordia disaster, many cruise lines choose to conduct the drill before the ship departs port for the first time.

[3] Laws in some places hold crew members liable to face civil charges if they voluntarily do not attend the muster drill.

On ferries, a safety briefing delivered through the PA system alerts passengers to the sound pattern of the emergency alarm and what to do if the signal is heard.

A muster drill in progress on Royal Caribbean cruise ship Grandeur of the Seas
A muster drill in progress on the Coral Princess
A muster assembly point signpost
The standard pattern for the general emergency alarm onboard a cruise ship.