Question 12 AB01 - Able Seafarer

The Correct Answer is C **Explanation for C (True bearings as observed from a vessel toward the light):** When a mariner uses a navigational aid such as a lighthouse with colored sectors, the purpose of the Light List is to provide information that can be directly applied to the mariner's chart and compass. The limits of a light sector are listed as **bearings** (directions), and these bearings are defined as the directions from which the mariner observes the light. * **"True bearings"** are used because charts and official nautical publications define directions based on True North, eliminating the variable effects of magnetic variation. * **"as observed from a vessel toward the light"** means the bearings listed in the Light List are the directions (e.g., 045°T to 090°T) that the vessel is sailing *on* when it crosses the boundary line between two sectors (e.g., white and red). This aligns with how the mariner plots positions and courses on a chart. **Explanation of why other options are incorrect:** * **A) Bearings given in the Light List are always magnetic:** This is incorrect. Bearings in official nautical publications (like the Light List) are standardized as True (referenced to True North) to maintain accuracy and consistency regardless of geographical location or magnetic variation. * **B) True bearings as observed from the light toward a vessel:** This describes the 'Reciprocal' bearing. While a lighthouse keeper might measure the light's limits this way when setting up the light (e.g., Shining 045°T), this is confusing for the navigator. The Light List provides the bearing the mariner is steering *on* when approaching the light, which is the reciprocal of the bearing from the light (C). * **D) Geographical positions outlining the area of the sector:** This is incorrect. While the sector covers a geographic area, the Light List defines the limits of the sector using easily plotted and understood directional lines (bearings), not by listing coordinates for the boundary points.