What is the purpose of using smoke signals on vessels?

The purpose of using smoke signals on vessels is primarily to provide a visible signal for rescue, particularly during the day. Smoke signals can be an effective means of attracting attention and enhancing visibility in daylight conditions, making it easier for search and rescue teams or other nearby vessels to locate a distressed craft. The distinct color and volume of smoke produced can be seen from a distance, thereby aiding in the timely and effective response to emergencies at sea.

While marking the location of wreckage and signaling distress in bad weather are important considerations, they do not specifically capture the primary use of smoke signals in distress situations. Indicating the passage of time is not relevant to the function of smoke signals, which is focused on emergency communication rather than timekeeping. Overall, the clear visibility afforded by smoke signals makes them a valuable tool in rescue scenarios during daylight.