To convert a compass course into a true course we can use the original equation. If we have steered a compass course of 200°, we have to plot a true course of 203° in the chart if the variation is 3° East or a true course of 190° if the variation is 10° West
True course: the course corrected for compass errors and plotted in the chart, tc and is equal to Course Over Ground (COG) or Course Made Good (CMG)
cc + var + dev = tc: this equation shows the connection between the compass course, its errors and the true course. It can also be read as: tc − var = cc + dev.
Magnetic courses are used for three reasons: To convert a true course into a compass course like we saw in the last paragraph. On vessels with more than one steering compass, also more deviation tables are in use; hence only a magnetic or true course is plotted in the chart.
Deviation: the compass error caused by electrical currents and / or metal objects.
Bearings taken with a handheld compass often don't require a correction for deviation, and are therefore useful to plot in the chart as magnetic courses. Note, that the actual course lines the navigator draws (plots) in the chart are always true courses, unless labeled as mc or cc. In chapter 4. chapter 4.
Marine compass. In China compasses have been in use since the Han dynasty (2nd century BCE to 2nd century CE) when they were referred to as “south-pointers”. However, at first these magnets were only employed for geomancy much like Feng Shui. Eventually, during the Sung dynasty (1000 CE) many trading ships were then able to sail as far as Saudi ...
Course directions are specified in degrees from north, either true or magnetic. In aviation, north is usually expressed as 360°. Navigators used ordinal directions, instead of compass degrees, e.g. "northeast" instead of 45° until the mid-20th century when the use of degrees became prevalent.
In navigation, the course of a watercraft or aircraft is the cardinal direction in which the craft is to be steered. The course is to be distinguished from the heading, which is the compass direction in which the craft's bow or nose is pointed.
A, B - Vessel's track. The path that a vessel follows over the ground is called a ground track, course made good or course over the ground. For an aircraft it is simply its track. The intended track is a route. For ships and aircraft, routes are typically straight-line segments between waypoints. A navigator determines the bearing (the compass ...
b. CNO and CMC shall administer the Correspondence Management Program within the Navy and Marine Corps, respectively.
SECNAV M-5216.5 JUNE 2015 June 2-4 a. Always coordinate during the drafting stage, before the correspondence is put into final form and submitted for signature. Ensure all coordination inputs are retained and filed with the file copy of the signed correspondence.
1. General. To a large degree, the image and effectiveness of the DON is portrayed by the tone, quality, and responsiveness of correspondence. Properly written correspondence that clearly and succinctly establishes a position, correctly and completely answers questions, and conveys the right message, all aid in the effective management and operation of the DON. In order to achieve this, correspondence must: