IMO SHIP IDENTIFICATION NUMBER SCHEME
(Circular letter No.1886/Rev.5)
The IMO ship identification number scheme was introduced in 1987 through the adoption of resolution A.600(15), as a measure aimed at enhancing “maritime safety, and pollution prevention and to facilitate the prevention of maritime fraud”. It aimed at assigning a permanent number to each ship for identification purposes. That number would remain unchanged upon transfer of the ship to other flags (s) and would be inserted in the ship’s certificates. When made mandatory, through SOLAS regulation XI/3 (adopted in 1994), specific criteria of passenger ships of 100 gross tonnages and upwards and all cargo ships of 300 gross tonnages and upwards were agreed.
SOLAS regulation XI-1/3 requires ships’ identification numbers to be permanently marked in a visible place either on the ship’s hull or superstructure. Passenger ships should carry the marking on a horizontal surface visible from the air. Ships should also be marked with their ID numbers internally.
The IMO ship identification number is made of the three letters “IMO” followed by the seven-digit number assigned to all ships by IHS Maritime (formerly known as Lloyd’s Register-Fairplay) when constructed. This is a unique seven-digit number that is assigned to propelled, sea-going merchant ships of 100 GT and above upon keel laying with the exception of the following: