USCG USCG GENNAV
Set 3 • Question #70 of 246
Launch Interactive Practice Room The reference datum used in determining the heights of land features on most charts is __________.
A
mean sea level
B
mean high water
✓ Correct Answer
C
mean low water
D
half-tide level
USCG NMC Regulatory Explanation
Mean Lower Low Water (MLLW) is the average of the lower low water height of each tidal day over a 19-year National Tidal Datum Epoch. It serves as the official chart sounding datum on NOAA nautical charts.
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