Question 16 MODU01 - Offshore Installation Manager

The Correct Answer is C. The steering and sailing rules for vessels in restricted visibility (specifically Rule 19 of the COLREGs - International Regulations for Preventing Collisions at Sea) apply to **all vessels** when they are **navigating in or near an area of restricted visibility**. This is because the purpose of the rule is proactive—to ensure safe navigation and collision avoidance before vessels are close enough to be in sight or to require the use of specific equipment. The presence of fog, mist, falling snow, heavy rainstorms, sandstorms, or any other similar causes of restricted visibility triggers the application of Rule 19, regardless of the vessel’s location (international or inland waters, where applicable) or equipment status. ### Why the other options are incorrect: **A) only if they have operational radar:** This is incorrect. While radar is a critical tool mentioned in Rule 19 for determining if a risk of collision exists and for taking avoidance action, the entire set of rules for restricted visibility (including sound signals and safe speed requirements) applies to all vessels, even those without radar or those whose radar is non-operational. **B) in sight of one another in fog:** This is incorrect. If vessels are in sight of one another, even in fog, they revert to the steering and sailing rules for vessels in sight of one another (Rules 11 through 18). Rule 19 specifically applies when vessels are **not** in sight of one another. **D) only if they are showing special purpose lights:** This is incorrect. The application of restricted visibility rules is determined by the environmental condition (visibility), not by the specific lights being displayed by the vessel. The requirement to use lights (like masthead, side, and stern lights) is mandatory at night, but the requirement to follow the maneuvering and sound signaling rules for restricted visibility applies regardless of the type of lights being shown.