During daylight with a vessel visible some distance away, what signalling method is most effective for attracting their attention?

A. A signalling mirror only works at night and is ineffective during daylight

B. A signalling mirror (heliograph), used to flash sunlight in the direction of the target — on a clear day this can be seen from a remarkable distance, far further than waving or shouting, and uses no consumable resources like flares

C. Orange smoke signals are always more effective than a mirror in bright daylight at long range

D. Shouting is the most effective method at any distance over open water

A. Emergency Position Indicating Radio Beacon — once activated (manually or automatically by water immersion), it transmits a distress signal with the vessel's identity and position via satellite to search and rescue authorities, continuing to transmit for an extended period to aid location

B. A backup liferaft repair kit component unrelated to communication

C. A type of personal flotation device with no signalling capability at all

D. A handheld torch used only for close-range signalling to nearby vessels

A. A PLB is only used for testing equipment ashore, never carried during an actual emergency

B. An EPIRB is typically registered to the vessel and often mounted/stowed for the whole crew, while a PLB is a smaller, individually registered device that a single person can carry on their body — useful if separated from the main group or liferaft

C. EPIRBs and PLBs are functionally and legally identical, with the only difference being colour

D. A PLB has no satellite connectivity and only works at very short range