Question 721 Rules of the Road

The correct answer is C) 225.0°. The International and Inland Navigation Rules require a power-driven vessel to exhibit a white masthead light that is visible over an arc of the horizon of 225.0 degrees. This is specified in Rule 21(a) of the Navigation Rules, which states that the masthead light shall be placed as nearly as practicable to the fore and aft centerline of the vessel and shall show an unbroken light over an arc of the horizon of not less than 225 degrees and so fixed as to show the light from right ahead to 22.5 degrees abaft the beam on either side of the vessel. The other answer choices are incorrect because option A) 022.5° is too narrow, option B) 112.5° is too narrow, and option D) 360.0° is too wide for the required arc of visibility for the white masthead light on a power-driven vessel.