Definition
When a vessel sails a series of short courses, as when tacking, each leg is resolved into northerly and easterly components using departure equals distance times sine of course and difference of latitude equals distance times cosine of course. Summing the signed components gives the net difference of latitude and total departure, from which a single equivalent course and distance follow. Departure is converted to difference of longitude by dividing by the cosine of the mean latitude.
Want to apply this on the water?
Ask Saily out loud for an example, a scenario or a simpler explanation.
Talk to Saily