BOTH INTERNATIONAL & INLAND At night, which light(s) is/are required to be shown by a dredge to indicate the side on which another vessel may pass due to an obstruction that exists?

Correct Answer: Option D — Two green lights

Rule 27(d)(ii) of the COLREGS and 33 CFR 83.27(d)(ii) mandate that a vessel engaged in dredging or underwater operations, when an obstruction exists, must display two red lights in a vertical line to indicate the side of the obstruction and two green lights in a vertical line to indicate the side on which another vessel may pass.