What is the signal for a vessel to confirm it is maintaining its course while being overtaken?

The signal for a vessel to confirm that it is maintaining its course while being overtaken is one short blast of the horn. This signaling is part of the sound signals prescribed by the International Regulations for Preventing Collisions at Sea (COLREGs). The use of one short blast indicates to the overtaking vessel that it will keep its course and speed, allowing the overtaking vessel to understand that it should proceed with its maneuver.

This communication is vital for the safety of navigation, as it clarifies intentions between vessels in close quarters. The other options signify different intentions or situations; for instance, two short blasts indicate a vessel is altering its course to starboard, while the international distress signal and continuous horn blowing signify emergencies or urgent situations that require immediate attention.