A vessel at LAT 38°03.0'S, LONG 49°38.0'W, heads for a destination at LAT 41°26.0'S, LONG 38°32.0'W. Determine the true course by Mercator sailing.

Correct Answer: Option A — 111.5°T

The true course by Mercator sailing is found by dividing the difference in longitude by the difference in meridional parts, yielding the tangent of the course angle as prescribed in Bowditch's navigational tables.