What color light may be used with a vessel's whistle?

What color light may be used with a vessel's whistle?

• A. Red
• B. White
• C. Green
• D. Yellow

Answer: (B)

When signaling with a whistle under the navigation rules, any accompanying light should be white. White is the neutral signaling color used for light signals because it doesn’t imply a specific direction or status like red or green navigation lights, which are reserved for indicating port and starboard lighting, or yellow, which is used for special purposes such as towing. Using a colored light could be misinterpreted as a navigation signal, whereas a white light clearly communicates the signaling intent without ambiguity.

When signaling with a whistle under the navigation rules, any accompanying light should be white. White is the neutral signaling color used for light signals because it doesn’t imply a specific direction or status like red or green navigation lights, which are reserved for indicating port and starboard lighting, or yellow, which is used for special purposes such as towing. Using a colored light could be misinterpreted as a navigation signal, whereas a white light clearly communicates the signaling intent without ambiguity.