BOTH INTERNATIONAL & INLAND Which of the following describes a vessel exhibiting the shapes shown in illustration D018RR below?

Correct Answer: Option A — dredging with an existing obstruction

Illustration D018RR shows two red lights (or shapes) over two green lights (or shapes). Per Rule 27(d)(ii), this configuration indicates a vessel engaged in dredging or underwater operations with an obstruction on one side and a safe passage side, requiring other vessels to navigate with extreme caution.