Question 26 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is D **Why Option D is Correct:** Option D is a direct reference to a specific exemption granted by the Inland Rules for Great Lakes vessels. Rule 23(d)(i) of the Inland Navigation Rules states that a power-driven vessel operating on the Great Lakes, 50 meters or more in length, may carry an all-round white light in lieu of the second masthead light and the stern light prescribed in Rule 23(a)(ii) (for vessels 50 meters or more in length). This substitution simplifies the required lighting configuration for certain larger vessels operating exclusively on the Great Lakes. **Why the Other Options are Incorrect:** * **A) Great Lakes vessels are exempted from the requirement to show yellow towing lights.** This is incorrect. Yellow towing lights (or "towing lights") are required for vessels engaged in towing by both the International and Inland Rules (Rule 24). There is no general exemption for Great Lakes vessels from this requirement. * **B) Sidelights for vessels over 50 meters are required to have only a two-mile range of visibility.** This is incorrect. According to Rule 22 (Visibility of Lights), sidelights for vessels 50 meters or more in length must have a minimum range of **three miles** (3 miles), not two miles. The two-mile range applies to power-driven vessels under 20 meters. * **C) The showing of a forward masthead light is optional for vessels under 150 meters.** This is incorrect. A forward masthead light is mandatory for all power-driven vessels underway (Rule 23). The length of the vessel determines the number and position of the lights, but it does not make the forward masthead light optional unless the vessel falls under specific small vessel exemptions (e.g., vessels less than 12 meters, which may use a single all-round white light).