Today, the port has acquired its standing within the intermodal transport system by constituting a nodal point between two transport modes. In seaports, one mode concerns maritime transport; in river ports, this mode concerns river transport. The nodal linkage between two different modes of transport should be functional, permitting efficient and secure movement of passengers, cargo, and vehicles. A civil port is a passenger, cargo, or combined port depending on the traffic that it serves. In a combined part, both passengers and cargo provide a significant percentage of the traffic. Of course, specialized ports exist, such as marinas (for harboring pleasure craft), fishing ports, and naval military bases.
There are two basic methods of loading and unloading cargo to vessels. They are lift on–lift off (Lo-Lo), which refers to the loading and unloading method, employing either the vessel’s gear or quay-side cranes, and roll on–roll off (Ro-Ro), which refers to the loading and unloading method conducted by horizontally moving equipment. Vessels allowing this type of loading and unloading are equipped with a loading ramp that permits the movement of cargo handling equipment and other vehicles (trucks, forklifts, straddle carriers, tractors, etc.) between quay and vessel.
At cargo ports, the type and packaging of cargo products determine the manner of loading and unloading as well as of other operations. Thus, the following basic categories of port terminals can be identified, each having varying equipment and operational features:
• General cargo terminals. These are terminals equipped with conventional cranes, which handle cargo in all types of packaging compatible with cranes. The packaging could be parcels, sacks, pallets, or containers. The latter should not, however, constitute a major percentage of the traffic, because otherwise a specialized container terminal would be required to improve throughput performance.
• Container terminals. In this case, containers are handled using special loading/unloading, transfer, and stacking equipment. They are typified by extensive yard areas for container stowage.
• Multipurpose terminals. These terminals combine a variety of functions in a single terminal, where containers, but also conventional general cargo or other packaged products, can be handled.
• Ro-Ro terminals. Here cargo is transferred within a roll on–roll off system, with loading and unloading of cargo by horizontally moving lorries, forklifts, tractors, and so on.
• Bulk cargo terminals. At these terminals, liquid or dry bulk cargo without packaging is handled. Usually, pumping machinery with suitable piping or grab cranes is used at these terminals.
The main quantity that may be affected by a suitably implemented national port policy lies in international cargo flow. Consequently, the initial and basic step in formulating a country’s port system includes the determination of those ports that will undertake to serve the flows of foreign trade, transshipment, or transit. These flows operate more-or-less independently of one another, and thus for simplification of the analysis, may be studied individually.
The basic criteria to be considered in developing a proposition as to the roles of a country’s ports may be classified into the following four groups:
1. The national and regional development policies of the country
2. The transportation infrastructure of the hinterland and its prospects
3. Existing port capacity and potential for development
4. Cargo forecasts for each port
After each of the three independent international flows has been examined, the findings should be pooled, to define the core of the country’s port system. Thus, the role of each port that participates in international cargo flow will be specified and the basic cargo throughputs can be determined. Considering these throughput values, and factoring in the national flows, master plans can be drawn up for individual ports.
Apart from international cargo flow, other aspects of the overall port development study are usually examined. Although these are not of primary significance in the formulation of the core of a national port system, they do have a role in evaluation of the main subsystems and in developing the final proposal. Such aspects include:
• Special bulk cargoes, such as coal, cement, petroleum products, grains
• Industrial ports
• Shipbuilding and ship repair
• Free zones
• Coastal shipping
• Passenger movement
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