to create the IMO ship identification number scheme aimed at the "enhancement of maritime safety and pollution prevention and the prevention of maritime fraud" by assigning to each ship a unique permanent identification number. Lloyd's Register had already introduced permanent numbers for all the ships in their published register in 1963, and these were modified to seven-digit numbers in 1969. It is this number series that was adopted as the basis for IMO ship numbers in 1987.

Unique and permanent