Question 16 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is C. **Explanation for C (navigating in or near an area of restricted visibility):** The steering and sailing rules for vessels in restricted visibility (Rule 19 of the COLREGs – International Regulations for Preventing Collisions at Sea) apply to **all** vessels, regardless of location (inland or international waters, provided COLREGs are applicable), when they are navigating **in or near an area of restricted visibility**. This Rule mandates specific conduct (such as speed adjustments and immediate engine readiness) and assumes that vessels may be operating solely by sound and radar, necessitating extra caution before the risk of collision occurs. The application is defined by the environmental condition (restricted visibility), not by vessel equipment or light displays. **Why the other options are incorrect:** * **A) only if they have operational radar:** Rule 19 applies to **all** vessels in restricted visibility. While having operational radar dictates specific actions (like using it effectively), the rules themselves apply universally, even to vessels without radar. * **B) in sight of one another in fog:** If vessels are "in sight of one another" (which means they can visually assess the situation), the rules for restricted visibility (Rule 19) cease to apply, and the rules for vessels in sight of one another (Rules 11-18) take precedence. Fog is a cause of restricted visibility, but if sight is established, the rules change. * **D) only if they are showing special purpose lights:** The rules for restricted visibility are operational rules concerning speed, maneuvers, and sound signals. They apply regardless of the vessel’s purpose or the lights it is showing. Special purpose lights (like those for towing or fishing) are for identification, not conditions of applicability for Rule 19.