What is the arc of a towing light?

A towing light is specifically designed to indicate the presence of a vessel engaged in towing operations. According to the COLREGs, the arc of visibility for a towing light is 135 degrees. This means that the towing light should be visible over an arc of 135 degrees from a specific point on the vessel, typically the stern where the light is mounted.

The 135-degree arc provides sufficient visibility to other vessels for safe navigation while allowing the towing vessel to maintain its operational function without presenting an excessive or confusing light signal. It effectively communicates the status of the vessel to prevent accidents and enhance situational awareness, particularly in circumstances where a tow may impact the maneuvers of approaching vessels.

This choice is grounded in international standards, ensuring uniformity and safety on the water. Other choices reflect incorrect arcs of visibility based on the specific requirements for different types of lights used for various purposes, such as anchoring or navigation lights.