33 CFR 334.6: Datum.

(a) Geographic coordinates expressed in terms of latitude or longitude, or both, are not intended for plotting on maps or charts whose reference horizontal datum is the North American Datum of 1983 (NAD 83), unless such geographic coordinates are expressly labeled NAD 83. Geographic coordinates without the NAD 83 reference may be plotted on maps or charts referenced to NAD 83 only after application of the appropriate corrections that are published on the particular map or chart being used.

(b) For further information on NAD 83 and National Service nautical charts please contact: Director, Coast Survey (N/CG2), National Ocean Service, NOAA, 1315 East-West Highway, Station 6147, Silver Spring, MD 20910-3282.