A tidal current, typical of open coastal waters, whose direction swings steadily around the compass each tidal cycle instead of reversing. In the Northern Hemisphere it usually turns clockwise. There is no true slack, only a minimum speed when the flow is weakest, and the pattern traced by the current vector over a cycle is an ellipse.
Out past the sea buoy it's a rotary current, so the set swings right round while we're on station.
Also heard as
- rotating current
- rotary tidal current
Related terms
Reversing current
A tidal current that runs back and forth along one line, flood one way and ebb the other, with slack at each change.
Current ellipse
The ellipse traced by the tip of a tidal current vector over one cycle, showing direction and speed at each stage.
Set and drift
The direction a current flows toward (set) and its speed (drift).
Tidal current
The horizontal flow of water that accompanies the rise and fall of the tide.