Welcome to the United States Power Squadrons' Chart Smart Seminar Compass Deviation (Section 2)

The TVMDC Formula  True Course T Variation V Magnetic Course M Deviation D Compass Course C  Add West Subtract East Subtract West Add East Deviation is different for each boat and depends upon a number of items. Our class deviation is assumed to be from the Sample Ship's Deviation Table.

Select the Deviation for the NEAREST tabulated entry for the Heading Select the Deviation for the NEAREST tabulated entry for the Heading. For greater accuracy, you may interpolate. SHIP'S COMPASS HEADINGS MAGNETIC HEADINGS USE WHEN CONVERTING TO MAGNETIC USE WHEN CONVERTING TO COMPASS Magnetic Heading Degress Deviation Degrees Compass Heading Degrees Deviation Degrees 000 015 030 045 060 075 090 105 120 135 150 165 180 195 210 225 240 255 270 285 300 315 330 345 5 E 4 W 8 W 11 W 14 W 15 W 12 W 9 W 6 W 3 W 3 E 6 E 9 E 12 E 14 E 15 E 13 E 11 E 8 E 000 015 030 045 060 075 090 105 120 135 150 165 180 195 210 225 240 255 270 285 300 315 330 345 4 E 3 W 6 W 9 W 12 W 14 W 15 W 11 W 8 W 4 W 8 E 12 E 14 E 15 E 13 E 11 E 9 E 7 E Chart Smart 2002

T _____ V _____ M _____ D _____ C _____ 140 Add West Subtract East Example #3 notes - deviation is assumed to be from the Sample Ship's Deviation Table (no interpolation); local variation is assumed to be 5 E 5 E 135 Compass course to steer is 147 degrees to make good a true course of 140 degrees 12 W 147

T _____ V _____ M _____ D _____ C _____ 204 Add West Subtract East Example #4 notes - deviation is assumed to be from the Sample Ship's Deviation Table (interpolate); local variation is assumed to be 11 W 11 W 215 Compass course to steer is 211 degrees to make good a true course of 204 degrees 4 E (interpolation req.) 211

End of Section 2D Compass Deviation