BOTH INTERNATIONAL & INLAND Your 18-meter vessel is under sail at night displaying sidelights, stern light, and a red light over a green light at the masthead. If you start the auxiliary engine and engage the propeller, which action must you take?

Correct Answer: Option A — turn off the red over green, turn on the white masthead light

Rule 25(e) dictates that a vessel proceeding under sail when also being propelled by machinery must exhibit the lights of a power-driven vessel. Therefore, the optional red over green lights must be extinguished, and the required masthead light for a power-driven vessel must be displayed.