How many masthead lights should a 45-meter tugboat towing two barges astern (total length 250m) display?

• A. 2
• B. 4
• C. 3
• D. 1

Answer: (C)

In COLREGS, the number of forward masthead lights a power-driven vessel displays can increase when the vessel tows another vessel or vessels. The length of the tow matters: a long tow requires an additional forward light to indicate the extended length ahead.

Here, the tugboat is towing two barges, making the total tow length 250 meters, which is over the 200-meter threshold. That situation calls for three forward masthead lights in a vertical line to signal to other vessels that a long tow is being carried. The tug’s own forward light plus two extra masthead lights for the tow give a total of three, ensuring the approach and maneuvering vessels can clearly gauge the extent of the tow.

If the tow were shorter (not exceeding 200 meters), fewer masthead lights would be required. The other options don’t align with the rule for long tows.