The Marine Distance Tables were first published in 1958 and have been revised a number of times since, with the last revision published in 1991 and have over many years become the de facto industry standard.
Commencing in 2004, they have now been fully revised with all distances being recalculated by AtoBviaC. The new distances and routes fully respect all mandatory and voluntary traffic separation schemes and recommended routing, as well as pilotage regulations where significant. In addition, the tables are aware of environmentally sensitive areas and will, wherever possible by default, avoid such areas resulting in a reduced environmental impact route. Environmental routing can be turned off if required to give the shortest distance route.
The Distance Tables are continually updated to reflect changes to routes as necessitated by Notices to Mariners and other regulatory requirements, together with the regular inclusion of new ports and terminals.
Updates to the Distance Tables are usually published every 2-3 months, and the Online Distances Tables are always updated to use the latest version.