Photo of the Week

Dead Reckoning

Photo: Eric Koser

The first task I learned was to plot our course on the charts. The Commanding Officer selects waypoints for an upcoming course in a digital mapping suite called Coastal.   Coastal sets a series of digital paths that each include a compass bearing (direction in degrees) and range (distance in nautical miles) between each waypoint. Then the navigator takes this same series of points and plots them by hand in pencil on the series of chart (the nautical term for maps). Each point is a pair of latitude and longitude points plotted as a small square. Given the expected cruising speed, the navigator can also estimate future positions of the ship, which are referred to as “dead reckoning” and are plotted with a half circle.