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Tides

What is Chart Datum approximately equal to in most UK tidal waters?

Short answer

Lowest Astronomical Tide

Chart Datum is normally close to Lowest Astronomical Tide in UK tidal waters. Soundings are below that datum and predicted tidal heights are above it, so check the chart note before combining them. Revise Tidal Definitions and Datum.

Sources and scope

Reviewed by Richard Moore on . This answer is scoped to united kingdom and general recreational seamanship; check the current chart, publication, local rules and official operational guidance before acting afloat.

Quick check

What is Chart Datum approximately equal to in most UK tidal waters?