A permanent number assigned by the International Maritime Organization (IMO) to each ship for identification purposes. The number will remain unchanged upon transfer of the ship to other flag(s) and will be inserted in the ship’s certificates. The IMO ship identification number is made of the three letters “IMO” followed by the seven-digit number assigned to all ships by Lloyd’s Register-Fair play when constructed. This is a unique seven-digit number that is assigned to propelled, seagoing merchant ships of 100 GT and above upon keel laying with the exception of the following:
- Vessels solely engaged in fishing;
- Ships without mechanical means of propulsion;
- Pleasure yachts;
- Ships engaged on special service (e.g. lightships, SAR vessels);
- Hopper barges;
- Hydrofoils;
- Air cushion vehicles;
- Floating docks and structures classified in a similar manner;
- Ships of war and troopships;
- Wooden ships.