What signal indicates that a vessel is being towed?

The signal indicating that a vessel is being towed involves the display of a special light or flag to ensure that other vessels are aware of the towing situation. This is vital for safety and navigational awareness in marine environments, as it allows other mariners to understand the dynamics of the situation and to maintain appropriate distances.

Displaying a light or flag serves as an acknowledgment of the vessel's status and helps to prevent potential accidents by signaling the nature of the operation to other vessels in the vicinity. This communication is essential for maintaining situational awareness and promoting safe navigation on the water.

The other options do not correctly describe the required signals for a vessel being towed. For instance, the requirements for horn signals are not specific to towing scenarios, and the use of an orange flag is not universally recognized as a distress signal related to towing. Likewise, the blue light is typically associated with specific types of vessels or operations but does not pertain directly to indicating that a vessel is under tow.