Michael wrote
The non-metric Navy's of the world use a standard
of 6,000 feet or 2,000 yards.

The US Navy uses the international nautical mile of 1852 m.



www.dtic.mil/doctrine/jel/new_pubs/jp1_02.pdf

http://geodesy.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf