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Abbreviations

Some of the navigation abbreviations used in the course

ACo:   Altered Course. This is a standard short hand format that is commonly used in logbooks to confirm a change in course.
     
COG:   Course over the ground This term describes the ground track or the proposed ground track of a vessel.
     
DMG:   Distance made good. Used to determine the actual distance a vessel has travelled in a straight line when tacking.
     
DR: dr Dead reckoning position. A position found using speed, time and a heading or heading and distance run.
Not considered accurate.
     
DTW:   Distance to waypoint. The distance to the next waypoint or destination.
     
EP: EP Estimated position of the vessel. Used when a position is worked out from the course, speed and leeway.
     
ETA:   Estimated time of arrival.
     
FIX: fix An accurate position of the vessel.
     
GNSS   Global Navigation Satellite System. Commonly called GPS, there are however a variety of systems in use.
     
GMDSS   Global Maritime Distress and Safety System. The network of satellites and ground stations used to detect transmissions from an EPIRB.
     
GT: Ground Track Ground track. A line marked drawn on the chart denoting the proposed or completed course over the ground of a vessel.
     
XTE:   Cross track error. Used to denote how far a vessel has strayed from the plotted ground track
     
SOG:   Speed over the ground. Describes the speed of a vessel over the ground including the effect of tide.
     
TMG:   Track made good. Gives the average course over the ground a vessel has made from the start point it's current position.
     
TTG:   Time to go. Time to the next waypoint or the destination.
     
WP: WP Waypoint. A small box plotted along the proposed course of a vessel. Usually marking a destination or change of course.