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All questions
Datum and depth

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.

Quick check

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