The evolution of the oil tanker

 By Peter Ward

Ships have been used to transport goods ever since trade crossed major waters. When global trade really took off around the late 1500s, all types of cargo would be transported on one type of ship, and a chief worry was to navigate the seas safely and avoid any pirates. Since then, transport vessels have come a long way, and in the oil and gas industry the technology, size and efficiency of tankers keep on improving…

(Cover photo by Pinterest)

As global trade picked up, ship owners saw enough demand to start specializing their goods. Instead of taking spices one year and precious metals the next, ships would focus on taking one type of cargo. Oil was originally moved in barrels or other containers, like other liquids, but shipping companies saw that by storing the liquids in special sections of the hull, they could transport more and take up less weight.

There’s more than one viewpoint on where the technology for oil tankers originated, but it is thought the first proper modern day oil tanker was built in 1886. The 2,700-ton Gluckauf was constructed in Newcastle-Upon-Tyne in the U.K. The ship had eight different compartments for cargo and was the first vessel that could have oil pumped directly into the hull, rather than brought on using barrels. The story of the Gluckauf didn’t end well however, as in 1893 the ship was wrecked on Blue Point Beach, Fire Island, New York. It was dislodged by tug boat but ran aground again when the hawser broke.

Others say the first real oil tanker was thought up by an oil producer in Baku, Azerbaijan. In 1978 he signed a deal with Sven Almqvist in Sweden to make blueprints for a tanker. The tanker, named the Zoroaster was built that year. The answer to who was first depends on your definition of a true modern day oil tanker.

An imagine of the Zoroaster. Credits: Тёрнер/

The oil industry led the way when it came to liquid cargo transport, and used tankers to carry refined fuel from refineries to customers. The fuel was stored in large tanks before being divided out and delivered to separate locations. This way of delivering fuel helped make the process vastly more efficient for the oil industry and its customers.

In the 1880s, oil trade between the West and Asia ramped up. Azerbaijan was one of the world’s largest producers of oil at the time, but only served the Russian market. Marcus Samuel and Fred Lane asked the Suez Canal Company, which had deemed moving oil through the canal as too risky, what type of tanker they would allow through, and made tankers based on those specifications. In 1892, the first tanker passed through the Suez Canal, taking oil from Russia to Asia.

The demand for oil went through the roof at the turn of the 20th century. World War One brought innovation, and shortages, to tankers. Tankers were designed to be able to perform “underway replenishment,” meaning U.S. tankers could refuel their ships while they were on their way to the U.K. But submarine warfare also caused a great shortage of tankers, as they were being destroyed faster than they were being built. As a shortage of gasoline can bring an army to a standstill, a great effort was undertaken by the U.S. to build new tankers. Between 1916 and 1921, 316 tankers were built with a total of capacity of 3.2 million long tons, a gigantic figure for the time. Before the war there was just over 2 million tons in operation in total.

World War II also brought great change to the oil tanker industry. Tankers were crucial for the war efforts of both sides and as such were targets as well. The number of tankers being built was boosted by new construction methods, which saw tankers being built in blocks then welded together.

During World War II, U.S. tankers made 6,500 voyages, carrying 65 million tons of oil and gasoline from the U.S. and the Caribbean to its allies in the major war zones. These tankers suppled 80 percent of the fuel used by vehicles during the war.

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After the war, tankers began to increase in size. As more refineries were built in places without access to oil, the need to ship crude oil in great quantities increased as well. The T2 tanker, the most common tanker used during World War II, was 532 feet long, with a capacity of 16,500 deadweight tonnage. Deadweight tonnage measures the maximum total cargo, provisions, fuel, ballast and crew weight that a ship can safely carry. Since then the size of tankers has increased every year. A modern ultra-large crude carrier (ULCC) can be 1,300 feet long and have a capacity of 500,000 DWT.

The main reason for the expansion in size of oil tankers is economical. The bigger a tanker is, the more oil it can move, and the more efficient the journey will be. Modern oil tankers fall into two categories—crude tankers and product tankers. Crude tankers transport the unrefined oil to refineries and product tankers move the petroleum products to markets where they can be sold. The product tankers are much smaller than crude tankers as their cargo is worth more and they need to transport less.

There are two systems used to categorize oil tankers based on size. The first is the Average Freight Rate Assessment (AFRA), which separates ships into six categories: General Purpose Tankers, Medium Range Tankers, Large Range 1, Large Range 2, Very Large Crude Carriers and Ultra Large Crude Carriers. The other system, the Flexible Market Scale puts oil tankers into six different categories: Product Tankers, Panamax, Aframax, Suezmax, Very Large Crude Carriers, and Ultra Large Crude Carriers.

Economies of scale

There are more than 600 VLCC class tankers today, carrying over 1 million gallons of oil each. They carry around one-third of the world’s tanker volume. The larger size vessels mean the price of shipping the oil has fallen to roughly 5-10 percent of the price per barrel.

The introduction of larger oil tankers has also brought with it a bigger danger of massive oil spills. After a 1989 spill in Alaska’s Prince William Sound, the U.S. government passed a regulation stating that all tankers in U.S. waters required double hulls by 2015. The double hulls are exactly as they sound: one hull inside the other as an extra layer of protection if the ship runs into trouble.

Now many tankers use automation to control certain aspects of the ship, like the engine rooms and cargo tanks. Further technology is being developed for oil tankers, including an ambitious project to develop a coating that repels water. This technology, being developed by a professor at UCLA, will create a layer of air between the ship and the water, reducing drag drastically and increasing speed and efficiency. The material that would coat tankers is made up of nanotechnology, and draws inspiration from small insects found in nature.

The oil tanker, used in some form for more than 130 years, has evolved from a basic vessel carrying oil to a behemoth of the sea, able to transport vast amounts of liquids in the most efficient manner possible. The future will no doubt see even more technology incorporated into tankers, and although it’s hard to imagine they’ll get bigger, they will continue to supply oil to all corners of the world for a long time yet.

SEE MORE: How water and energy mix by Nicholas Newman 

about the author
Peter Ward
Business and technology reporter based in New York. MA in Business Journalism at Columbia University Journalism School 2013. Five years experience reporting in the U.S., the U.K., and the Middle East.