What is the most common visual distress signal used by boats?

The most common visual distress signal used by boats is the red flare. Red flares are widely recognized as an effective means of indicating distress on the water. They are designed to produce a bright red light visible from a significant distance, making them a prominent option during both day and night. The intensity and color of the light signal ensure it stands out against the natural background, alerting other vessels and rescuers to the presence of someone in need of assistance.

While bright orange smoke signals and a white flag with a contrasting symbol can also be used to indicate distress, they are not as universally recognized as red flares in maritime situations. Green lights are typically used for navigation and do not convey a distress signal. The established international maritime conventions recognize red flares as a standard distress signal, which contributes to their commonality and effectiveness in emergency situations on the water.