(1) open port
The water level change in the harbour is called open exposure to the same port outside Hong Kong
(2) closed port
At the entrance of the port, the water level of the harbour is separated from the outer sea, so that the water level of the harbour is not changed with the change of tide, so that the port in the harbor with sufficient water depth is called a closed port. The London port of England belongs to this class.
(3) mixed port
The ports of open port and closed port are called mixed port. The Belgian port of Antwerp belongs to this class.
Classification by status
(1) international port
The port of ships from all over the world is called an international harbor. Such as Shanghai port and dalian port of China, Rotterdam and London port, etc.
(2) national port
The port of the ship which mainly depends on the ship to the domestic port is called a national port.
(3) regional port
The port of a ship which is mainly anchored to a certain area of the country is called a regional port