What signals must a fishing vessel make when it is operating in reduced visibility?

When a fishing vessel is operating in reduced visibility, it is required to sound one prolonged blast. This signal serves to alert nearby vessels of its presence, indicating that it is potentially restricted in its ability to maneuver. The use of a prolonged blast is standardized in maritime navigation rules to promote safety by ensuring that other vessels can detect the fishing vessel even when visual cues are limited due to fog, rain, or other obstructions.

The prolonged blast lasts for about four to six seconds. The reason for this specific duration is to distinguish it from shorter signals, which might convey different navigational intents. In conditions of decreased visibility, it is crucial for vessels to communicate their status and intentions clearly to avoid collisions, making this signal indispensable for safe navigation.

Other signals, such as short blasts or combinations of blasts, correspond to different situations or maneuvers and are not appropriate for use in the context of fishing vessels operating under reduced visibility conditions. The proper signal helps maintain awareness and fosters a safer maritime environment.