What is the arc of visibility of a sidelight?

The arc of visibility of a sidelight on a boat is 112.5 degrees. This design is specifically established to ensure that the sidelight is visible over an adequate angle to provide other vessels with necessary navigational information. Sidelights are typically installed on the starboard (right) and port (left) sides of a vessel, displaying green and red lights, respectively.

The 112.5-degree visibility is significant because it allows these lights to be seen by other vessels from the side and partly from the front, effectively signaling the vessel's heading and allowing for safe navigation in proximity to other boats. This specific angle is part of the International Regulations for Preventing Collision at Sea (COLREGs), which emphasize the importance of visibility and signaling among vessels to prevent accidents.

In contrast, the other angles provided do not conform to the established regulations for sidelight visibility, and therefore, they do not represent the correct answer. Understanding the specific visibility angles of navigational lights is crucial for safe operations and adherence to maritime regulations.