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

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

D. 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

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

B. A backup liferaft repair kit component unrelated to communication

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

D. 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

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