Question 24 ONC03 - Master LT 500-1600 GRT

The Correct Answer is A. **Explanation for Option A (Correct):** Option A is correct because it directly reflects the exception provided in the International Regulations for Preventing Collisions at Sea (COLREGs), specifically Annex I, Section 9 (Horizontal and vertical positioning of lights and shapes). For Wig-Craft (Wing-in-Ground craft), which operate at high speeds close to the surface and are structurally unique, it is often physically impossible to meet the standard spacing and positioning requirements for lights (especially masthead lights) without compromising the craft's design or operation. COLREGs Annex I, 9(a)(iv) addresses this issue: > **"A wing-in-ground (WIG) craft shall only comply with the spacing requirement for masthead lights as closely as possible, as determined by her Government."** This provision acknowledges the inherent design constraints of WIG craft and allows for the lights to be positioned as close to the required spacing as possible, provided this arrangement is certified and determined acceptable by the craft's flag state (her government). **Explanation of Incorrect Options:** * **B) An all-round light should be substituted for the after-masthead light and the stern light.** This is a substitution rule mentioned elsewhere in COLREGs (e.g., for vessels under 12 meters where two masthead lights are required), but it is not the specific regulatory relief granted to WIG craft regarding the spacing of mandatory masthead lights. WIG craft generally require two masthead lights in compliance with the requirements for power-driven vessels over 50 meters, and the exception applies to the *spacing* of these required lights, not their substitution. * **C) The WIG must carry only the lights that comply with the rules; the others may be omitted.** This is incorrect and dangerous. A WIG craft, being a power-driven vessel, is obligated to carry the full suite of required navigation lights (masthead lights, sidelights, stern light) to indicate its status and orientation. Omitting required lights is a serious violation of COLREGs and compromises safety. The rule allows for modification of *spacing*, not omission of required lights. * **D) The WIG must be altered to permit full compliance with the rules.** This defeats the purpose of the exception. The exception exists precisely because altering the WIG craft to achieve full compliance with standard light spacing would be structurally or operationally infeasible or impractical, and Annex I explicitly permits non-standard spacing in this specific scenario.