What is the minimum length of an anchored vessel that is required to show both forward and aft masthead lights?

• A. 60 meters
• B. 40 meters
• C. 30 meters
• D. 50 meters

Answer: (D)

When a vessel is at anchor, the light rules focus on making its presence and size visible to other vessels. The basic requirement is a white light to mark the vessel’s presence at night. For larger vessels, the regulations add that two masthead lights—one forward and one aft—must be shown to convey the vessel’s length and orientation more clearly. The threshold for needing both forward and aft masthead lights is 50 meters in length. So, a vessel that is 50 meters or longer must display both forward and aft masthead lights when anchored, while shorter vessels are not required to show those two masthead lights.