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, you must_______.

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

COLREGS Rule 25(e) requires a sailing vessel under engine power to exhibit the lights of a power-driven vessel. The optional red-over-green masthead combination is extinguished, and the standard white masthead light is illuminated.