644. Your vessel receives a distress call from a vessel reporting her position at LAT 5° 24' N, LONG 31° 16' W. Your position is LAT 2° 39' S, LONG 39° 24' W. Determine the distance from your vessel to the vessel in distress by Mercator sailing.

Calculate the Mercator sailing distance by determining the difference in meridional parts and longitude, finding the course angle, and then calculating the distance using the latitude difference and the cosine of the course angle, resulting in a distance of 688.7 nautical miles.