History of The Oil Tanker - Closure of The Suez Canal

Closure of The Suez Canal

The oil spill caused by the Torrey Canyon in 1967 caused a public awareness about the environmental dangers of oil tankers. Oil companies united in 1970 in the Oil Companies International Marine Forum to become involved in the following issuing of rules such as MARPOL 73. In 1968 also the International Tanker Owners Pollution Federation was founded to indemnify the victims.

For tanker owners, the Six-Day War of 1967 was of greater importance. The Suez Canal closed until 1975 and freight rates skyrocketed because of the shortage of tonnage now ships had to pass the Cape of Good Hope. Even larger tankers were now built, as the limitations of the Suez Canal were not governing anymore. In only a couple of years the size of tankers quadrupled to more than 500,000 long tons and there were even plans for tankers of 1,000,000 long tons. In 1969 the first ULCC's were built.

The world's largest supertanker ever was built for Tung Chao Yung in 1979 at the Oppama Shipyard of Sumitomo Heavy Industries, Ltd. as the Seawise Giant. This ship was built with a capacity of 564,763 DWT, a length overall of 458.45 metres (1,504.1 ft) and a draft of 24.611 metres (80.74 ft). She has 46 tanks, 31,541 square metres (339,500 sq ft) of deck, and is too large to pass through the English Channel.

Seawise Giant was renamed Happy Giant in 1989, Jahre Viking in 1991. From 1979 to 2004 she was owned by Loki Stream, at which point she was bought by First Olsen Tankers, renamed Knock Nevis and converted into a permanently moored storage tanker. The Batillus class supertankers are the biggest ships ever constructed by gross tonnage.

Although the tanker fleet increased around 12 percent annually around 1970, a shortage on tonnage remained. In 1973 this resulted in an enormous increase in new building orders, especially from oil majors that wanted to gain on the quicker deciding independents, who could ask enormous rates for their vessels. Where the existing tanker fleet comprised some 150 million long tons, in a quarter of a year a tonnage of 75 million was ordered, although new build prices doubled.

The increase in scale brought a new problem. Until then, the washing of tanks after cargo discharge was done by water. In December 1969 three tankers exploded during tank washing. The Dutch Shell tanker Marpessa sank off Dakar and became the largest merchant vessel ever lost. The other two, the British Shell tanker Mactra en the Norwegian Kong Haakon VII were damaged heavily, but remained afloat. Shell investigated the matter and came to the conclusion that water drops that impact steel with high velocity generates static electricity that can cause explosions in combination with cargo vapors. This only became apparent with the large sizes of the tanks of VLCC's.

The solution was found by filling the cargo tanks with inert gas (IG), reducing the oxygen level such that the tank remains below the explosive limit. The use of IG is seen as the biggest step in increasing tanker safety. Ten years later however, fifty people were killed when the Betelgeuse exploded at Whiddy Island in Bantry Bay. The Total tanker was still not fitted with inert gas. The Energy Concentration did have this system, preventing an explosion when it broke in two on 21 July 1980 during discharge at Europoort. It has also saved many lives during the Tanker War.

Washing with water in combination with the Load on Top system was replaced by crude oil washing (COW), a method developed by BP. The advantages were cleaner tanks, no corrosive sea water in cargo tanks and no polluted sea water being pumped overboard.