The pair of values that describes a current. Set is the true direction toward which the water moves; drift is its speed, usually in knots. Navigators compute set and drift from the difference between a dead-reckoning position and a fix, and current tables and tidal stream atlases give them hour by hour. Currents are named for where they go, the opposite of winds, which are named for where they come from.
Set and drift worked out at 045 at 1.8 knots over the last hour, so come left ten degrees.
A northerly wind blows from the north but a northerly set flows toward the north; getting that backwards is a classic exam and wheelhouse error.
Also heard as
- set
- drift
Related terms
Tidal current
The horizontal flow of water that accompanies the rise and fall of the tide.
Tidal diamond
A lettered diamond symbol on British-style charts linked to a table of tidal stream direction and rate hour by hour.
Rotary current
An offshore tidal current whose direction keeps swinging round the whole compass during each tidal cycle.
Current ellipse
The ellipse traced by the tip of a tidal current vector over one cycle, showing direction and speed at each stage.