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course made good The resultant (straight line) direction between any two points on your vessel's track. Five miles east and then five miles north, would lead to CMG of 045 T. CMG should be distinguished from Course Over Ground (COG), which is a dynamic real-time value obtained from GPS. See Course Over Ground. Anything referring to the past or to the future would be an actual CMG or an anticipated one. COG, on the other hand, is the live course we are making good relative to the fixed ground at the moment, which we know only because we have a GPS that keeps track of our position several times a second and from this data it can determine which way we are tracking this instant. According to Bowditch, these are both misnomers in that they (NGA editors) would prefer the word "course" be restricted to directions steered or intended to be steered through the water with respect to a reference meridian.... but this is a bit difficult to coordinate with modern conventions in GPS terminology. See also Tricky Terms in Navigation. Abbreviation:  CMG

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