When a vessel is towed, what sound signal is required by the towing vessel?

Answer: C — One prolonged blast followed by three short blasts

When a vessel is towing another vessel, the sound signal required by the towing vessel is a prolonged blast followed by three short blasts. This signal is significant for ensuring safety on the water and communicates the specific action of towing to other vessels in the vicinity. The prolonged blast serves as a warning signal that indicates the presence of a tow, making other vessels aware that there may be navigational restrictions associated with the towing operation. The three short blasts that follow indicate the towing vessel's intention to communicate further, essentially alerting nearby vessels regarding its maneuverability and the nature of its operations. This sequence of blasts is designed to minimize the risk of collisions by facilitating clear communication about the towing situation, particularly in conditions of reduced visibility or busy waterways. In a maritime context, adhering to these sound signal conventions is essential for maintaining navigational safety and understanding between vessels.