Moving goods by sea or waterways is by far the most economic method of transport in terms of the cost per ton – mile (cargo volume multiplied by distance carried). It is estimated that over 95% of the world’s trade is carried by sea, and that this represents some 20 trillion (20,000,000,000,000) ton-miles. If this figure seems mind-boggling, another statistic shows that the volume of goods carried by sea has increased nine-fold in the last 50 years.
Clearly sea transport plays a crucial part in international trade and improved efficiency in ships and cargo handling has helped to reduce the overall costs of sea transport in real terms year on year, encouraging this steady increase in volumes. The commodities, which are moved in the largest volumes across the world’s oceans, are crude oil and oil products, coal, metal ores and grains.