Maryland School of Sailing · video

What this video covers

Navigators convert true, magnetic, and compass bearings using the TVMDC table to account for variation and deviation.0:09 The acronym stands for True, Variation, Magnetic, Deviation, and Compass. When moving left to right across the table, add west values and subtract east values.0:44 When moving right to left, reverse the process by adding east values and subtracting west values.0:51 For example, converting a 140-degree true bearing with 3 degrees west variation results in a 143-degree magnetic bearing.1:10 Applying a 2-degree east deviation to that 143-degree magnetic bearing yields a 141-degree compass bearing.1:26 Reversing the calculation from 141-degree compass back to true requires adding the 2-degree east deviation to reach 143-degree magnetic, then subtracting the 3-degree west variation to return to 140-degree true.1:44 Mastering the left-to-right rule of adding west variation or deviation provides the foundation for all four directional conversion calculations.2:05

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