Question 3 ONC02 - Second Mate/Third Mate Unlimited Tonnage

The Correct Answer is A **Why Option A ("A law enforcement vessel") is correct:** Under the Inland Navigation Rules (specifically 33 CFR § 84.14), a flashing blue light is an identification signal used exclusively by federal, state, or local law enforcement vessels. This signal is used to alert other vessels of their presence and operational status, particularly when engaged in enforcement duties. **Why Option B ("A work boat") is incorrect:** Work boats or vessels restricted in their ability to maneuver typically use specific day shapes (ball, diamond, ball) and all-round lights (red, white, red) or appropriate masthead and sidelights, not a flashing blue light for identification. **Why Option C ("A vessel engaged in a race") is incorrect:** Vessels engaged in a race (such as sailboats) do not typically use specialized lights for their activity under the standard Navigation Rules. They must still comply with the general rules of the road (e.g., proper running lights). **Why Option D ("A vessel transferring hazardous cargo") is incorrect:** A vessel handling or transferring hazardous cargo (such as an oil tanker or chemical carrier) does not display a flashing blue light. They are generally identified by day shapes (e.g., a cylinder) or required placards, and their running lights must comply with standard rules, not a unique flashing blue light.