Question 25 ONC02 - Second Mate/Third Mate Unlimited Tonnage

The Correct Answer is B **Explanation for Option B (less than 12 meters in length):** International Regulations for Preventing Collisions at Sea (COLREGs), Rule 23 (Power-driven vessels underway), specifies the placement requirements for the masthead light. Annex I (Positioning and Technical Details of Lights and Shapes), Section 3(b), provides specific relief for smaller vessels. It states that, for a power-driven vessel of **less than 12 meters in length**, the masthead light (or all-round white light if used instead) may be displaced from the fore and aft centerline if: 1. It is not practicable to place the light on the centerline (e.g., due to space limitations or structural constraints). 2. The light is placed in the fore and aft centerline plane passing through the vessel’s keel. Since the question specifically asks which vessel *may* locate the light at other than the fore and aft centerline, the category of vessels less than 12 meters in length is granted this general permission under specific conditions related to practicality. **Explanation for Incorrect Options:** **A) which has separate sidelights carried on the outboard extremes of the vessel's breadth:** While the lateral spacing of sidelights is a requirement for certain vessels, this placement rule does not inherently exempt the vessel from the requirement to place the masthead light on the fore and aft centerline. Masthead light placement is addressed separately from sidelight breadth requirements. **C) engaged in fishing:** A vessel engaged in fishing must still comply with the general rules for the positioning of its masthead light (if required, as many fishing vessels use an all-round white light instead of a traditional masthead light) unless it falls into a size category (like less than 12 meters) that grants relief. The activity itself does not grant exemption from the centerline requirement. **D) less than 20 meters in length:** While 20 meters is a critical threshold for many COLREGs rules (e.g., sound signal requirements, specific light spacing), the specific exception allowing the masthead light to be located off the fore and aft centerline applies only to vessels **less than 12 meters** in length, not those less than 20 meters. Vessels between 12 and 20 meters must generally adhere to the centerline rule.