Rapid economic growth in China and India has led to a boom in world trade, which in turn has brought good times for the shipping industry.

Freight rates have soared as Asian demand for raw materials and the export of finished goods have risen. Oil tankers are in the highest demand and the average cost of leasing a very large crude carrier (VLCC) is now $170,000 (£85,700) a day compared with an average of about $60,000 last year.

The busiest shipping route is from the Arabian Gulf to China, a journey that takes 45 days.

The cost of buying a new ship has also risen and a VLCC, which can carry up to two million barrels of oil, now costs $200 million, compared with $60 million in 2002.

An oil tanker analyst at Gibsons, a shipbroking firm in London, said: “There's a combination of factors driving ship prices higher. Fuel costs have gone up more than a third, steel is expensive and yards only have a limited capacity. There are still too few ships in the world so merchants can be left with a cargo and no means to move it. There are high premiums to be made on tankers at the moment.”

Despite higher freight rates, many shipping firms are under pressure because of their own rapidly rising costs. The price of oil has doubled in the past year, leading to a big increase in fuel bills for all ships.

The industry is exploring a number of ways to reduce its fuel consumption and to cut emissions of carbon dioxide, nitrous oxide and other chemicals.

Better engine technology promises the biggest efficiency gains, but shipbuilders are also investigating how to improve the design of hulls and propellers. There is even research into whether new paints can be used to coat ship hulls to reduce drag in the water.

Bill Box, a spokesman for Intertanko, a trade association for tanker ships, said: “The cost of fuel has given impetus to the search for greater efficiencies. Ships are burning less fuel than they used to, but because the world fleet has grown in size the overall amount of CO2 emitted has increased. The industry is conscious of that and is working on it.”

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