Celestial navigation glossary
Set and drift
A current's direction (set, the way it flows) and the distance it carried you (drift); drift ÷ hours is its rate.
Where the course teaches it
Currents: set, drift and the course to steer, in the module The fix. Plot two or more lines of position, including a running fix, and judge the fix.
Taught alongside it
- Fix
- Where two or more lines of position cross: your position at the time of the sights.
- Universal plotting sheet (UPS)
- A blank sheet you set up for your latitude, with the longitude scale shrunk by cos(latitude).
- Running fix
- An earlier line advanced along the course by the distance run, crossed with a later one.
- Estimated position (EP)
- A DR with the current (and leeway) allowed for.
- Course to steer (CTS)
- The heading that, with the current, makes good the track you want: head up into the current.
- Cocked hat
- The small triangle three lines make; the fix is taken inside it.