PREDICTED SET & DRIFT CORSE

PREDICTED COURSE & SPEED BASED ON SET & DRIFT

See Set & Drift Determination page

1) Label present fix with "O"
2) Extend Set/Drift line for one hour of current, or Drift rate
  • the rate of Drift is the distance you extend the line (ie: 2.1 miles in example)
  • label end of extended line with "W"
3) Plot new course line from Fix (O).
  • example below goes back to first fix (0800).
4) Plot line from extention (point W) to cross new course at a distance equal to boat speed to Fix (O) (ie: original boat speed=8.0 knots so line W - P is 8 miles)
  • label intersection on new course line with "P"
5) Measure line "OP" length; it will be the Speed-Made-Good on new course, or new speed due to effects of current.
6) Determin bearing of line "WP" from W to P
  • this bearing is the new course to steer for the new course to off-set effects of current