Chart Navigation & Plotting · Tides
'Charted depth' on a U.S. chart is measured from:
- AMean high water
- BMean sea level
- CThe chart sounding datum (Mean Lower Low Water on U.S. charts)✓ Correct
- DThe highest astronomical tide
Explanation
On U.S. NOAA charts the sounding datum is Mean Lower Low Water (MLLW). Charted depth plus the height of tide from the tide tables gives the actual depth of water at a given time.
Authority: U.S. Chart No. 1; NOAA charting standards
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