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USCG Exam PracticeChart symbols and abbreviations (Chart No. 1)

A mariner is using a US nautical chart and notes that a lighthouse symbol (star) and a nearby buoy symbol (circle) are both shown. The mariner needs to plot the precise geographic position of each aid. Which statement is correct?

  1. The precise position of the lighthouse is the centre of the star; the precise position of the buoy is the centre of the circle.Correct
  2. B. The precise position of both aids is taken from the outermost point of their respective symbols.
  3. C. The precise position of the lighthouse is the centre of the star; the precise position of the buoy is taken from the tip of the buoy symbol.
  4. D. The precise position of both aids is the centre of the circle, as all aids use the same position convention.

Why A is correct

Chart No. 1 conventions, as reflected in the Light List Position Symbol entry, specify that the centre of the star is the charted position for a lighthouse and the centre of the small circle is the charted position for a buoy. Applying the wrong convention to either aid will introduce a position error. Light List — Position Symbol.

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A mariner is using a US nautical chart and notes that a lighthouse… — USCG Exam Practice · CaptainsGround