Where is the Masthead White light located and what is its visibility arc?

• A. White masthead light is located at the stern.
• B. White masthead light visible 360° around the horizon.
• C. White masthead light visible from dead ahead to 90 degrees to each side.
• D. White masthead light visible from dead ahead to 112.5 degrees on either side, for a total of 225°.

Answer: (D)

The white masthead light is placed high on the foremast at the bow, so it can be seen from the front of the vessel. Its visibility arc is 225 degrees, extending from dead ahead (0 degrees) to 112.5 degrees to each side. In other words, you can see it anywhere in the forward half of the vessel and slightly to the sides, but not directly behind. This arrangement helps other vessels understand the vessel’s forward direction while avoiding confusion with lights intended for the stern and rearward directions.