Question 3 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is A **Why option A ("A law enforcement vessel") is correct:** Under the Inland Navigation Rules (33 CFR Subchapter E), a flashing blue light is a signal reserved for and displayed by law enforcement vessels, such as those operated by the U.S. Coast Guard, state marine patrols, or local police, when they are engaged in enforcement duties. The light is intended to signify authority and alert other vessels to their presence for official purposes. **Why the other options are incorrect:** * **B) A work boat:** Work boats (vessels constrained by their draft or engaged in dredging or underwater operations) display specific lights and shapes prescribed by the Rules (e.g., restricted maneuverability signals like red-white-red lights, or shapes). They do not use a flashing blue light for identification. * **C) A vessel engaged in a race:** Vessels engaged in races generally adhere to standard navigation lights unless specific race rules dictate otherwise, but the flashing blue light is not a recognized signal under the Inland Rules for racing. * **D) A vessel transferring hazardous cargo:** Vessels transferring hazardous cargo (or engaged in towing dangerous tows) must display the prescribed standard navigation lights and potentially warning shapes, but the flashing blue light does not indicate the nature of the cargo being transferred.