Tidal streams and gates in Yachtmaster passage planning

Tidal-stream set and rate affect track, speed over ground and passage time. Build the stream from the chart, diamond or atlas information valid for the relevant hour and range, then compare the prediction with observed progress. Wind opposing tide can create shorter, steeper seas, but the actual risk also depends on depth, topography, wave system and local conditions.

Treat a tidal gate as a decision point with an arrival window, uncertainty allowance and latest safe time—not merely the hour the stream changes. Work backwards from the gate through realistic boat speed and adverse cases, then name the early diversion or waiting option if the margin starts to disappear.

For pilotage, translate set and rate into a deliberate approach track, speed and monitoring plan. Use transits, clearing bearings, depth, fixes and visual/radar evidence to detect cross-track movement; brief an abort point before the stream, traffic or shallow water removes the option.