Navigation and Seamanship

1.4.5. Special charts

Special charts

DECCA charts : These are normal basic navigational charts with the appropriate Decca lattice superimposed on them, and can be used in place of corresponding basic navigational charts. The number of Decca chart is the same as that of the basic chart but is prefixed L (D) and suffixed with Decca chain number.

CONSOL charts : These are mostly used in air-navigation but may be used as an aid to ocean navigation also. They show great circle bearings of the consol stations.

LORAN charts : Loran chains used for ocean navigation cover most of the Northern Hemisphere, and parts of Central Pacific Ocean.

Routing charts : These charts give important information for planning of passages across the oceans. Separate charts recommending routes for different months of the year are published for each ocean and they give recommended tracks and distances between ports, average meteorological and ice conditions and ocean currents.