The major ports of the world service vessels in deep-sea shipping.   Now the major ports are located in Asia, mainly China, reflecting Chinas new and central place in international trade. The increasing difference in port size reflects changes in ship operations and the effort to exploit economies of scale to reduce the transport cost per tonne or container. By concentrating port visits for vessels on intercontinental routes to a few main ports in each continent and employing smaller feeder vessels to carry the cargo to its final destination, it is possible to carry the cargo in larger vessels on the longest leg of the voyage. Such a hub and feeder operation requires multiple discharging and reloading in the hub port.   Modern efficient cargo handling changed this trade-off between direct port-to-port operations and hub and feeder and led to a concentration of intercontinental transport operations to a limited number of major ports in each continent. This allowed for employing large vessels on the main trade routes between these major ports.

 

 Picture 13

 

Figure 11: Major ports. Total traffic in thousand tonnes.

Source UNEP/GRID-Arendal, (2006) http://qed.princeton.edu/index.php/Image:Major_Merchandise_
Ports_and_Likely_Waste_Transit_Points,_2003.jpg

http://maps.grida.no/go/graphic/major_merchandise_
ports_and_likely_waste_transit_points

 

The turnaround time in port represents one of the major changes in shipping in the last 50 years. For general cargo or manufactured intermediary and finished goods, the main effect of containerization was to facilitate cargo handling by introducing special vessels to pack the cargo. Before containerisation, cargos came in smaller units of different shapes, weight and volumes. Storing cargo on board required many hands and different arrangements in the cargo hulls. Containerisation changed this, standardising the cargo unit, the vessel hold and the cranes that lift the cargo on board the vessel. One important effect is that container vessels can be loaded or discharged in 24 hours against the former 1-2 weeks for general cargo vessels.

 

A similar but less striking change characterise bulk shipping. The pumps and port equipment in the oil terminals are more efficient than before and other important improvements have reduced time in port for dry bulk.

 

Another characteristic of port development is the establishment of specialised terminals within the port area. These terminals often operate for profit and are not owned nor operated by the port authorities. They handle only one kind of cargo and are efficient than the traditional ports. This also contributed to the shorter port stay in current ship operations.

 

Hence, vessels therefore sail for a greater part of the year than before and can make more cargo carrying trips and carry more cargo per year. This is so especially in the container trades. The resulting efficiency as reported in Figure 3.13. Since efficiency also depends on fleet capacity relative to transport demand or whether there is excess transport capacity or not, efficiency also varies with market conditions. Even so, we see a positive trend in the container fleet efficiency from the 1970s, the first decade after the introduction of containers. The reduction in tanker efficiency between 1970 and 1990 on the other hand reflects the huge excess supply of tankers that followed the intense contracting in the beginning of the 1970s.

 

 

 tons_carried

 

Figure 12: Tons cargo carried per deadweight ton (dwt) of the world fleet. Selected years

Based on UNCTAD (2011, 82, table 3.9))