Many a time ships disappeared or could not be traced as their SOS signal could not be received. It presumed that the first help for a ship in trouble would come from a near-by vessel rather than from a distant coast station. Both kinds of equipment are complex and slow to operate. They are both very limited in range. All navigational and weather safety information has to be transmitted twice to traffic in the same area.
Coastguard equipment varies enormously from one part of the world to another.
With the growth of maritime satellite communications in the late 1970s came a realization by the International Maritime Organization that it was time to resolve all these problems through a radical update of the whole distress and safety system. The radio equipment carried by the ship will depend not on its gross tonnage, but on its area of operation, so that even a small ship in mid-Pacific will still be in touch with the land, as well as the other ships elsewhere in the Pacific. The equipment required on board ships will depend not on their tonnage as was the case upto now, but on the sea areas in which they operate. The new system will divide the oceans into four areas. A distress message can be sent simply by pressing a button.