(a) The regulations in this subpart shall apply to the structures which are located within the boundaries of the Coast Guard districts hereinafter defined.(b) Geographic coordinates expressed in terms of latitude or longitude, or both, are not intended for plotting on maps or charts whose referenced 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.CGD 86-082, 52 FR 33810, Sept. 8, 1987