Tidal-stream Rate

The speed of a tidal current at a stated position and time.

Rate is normally expressed in knots and paired with set, the direction towards which the water flows. It changes through the tidal cycle and with springs, neaps, depth and location, and can differ substantially across a channel or near a headland.

Atlas and chart values are predictions or representative values and may require interpolation and adjustment for tidal range. Wind, river discharge and local eddies can alter actual flow, so rate should be checked against observations where it materially affects safety.