Calculating Distance Using Parallel Sailing
What is Parallel Sailing? Parallel sailing means sailing along the same parallel of latitude. In parallel sailing, you maintain a true course of 90 ° East or 270 ° West. Moreover, the distance sailed would be the departure at the latitude (distance=departure). Formula: 1. Cos lat = Departure/Dlong Deriving the formula will give us: 2. Departure= Cos lat x Dlong 3. Dlong= Departure/Cos lat Sample Problem: 1. The final and initial courses are given. What are the course and distance? Position A= 19 ° N, 070 ° E Position B= 19 ° N, 100 ° E Solution: Step 1: To find the distance, calculate the difference of longitude (Dlong) first. Long A= 070 ° E Long B= 100 ° E (Same sign subtract, different sign add.) Dlong = 030 ° E (Sign of Dlong is East because the direction of the ship i...