The Advent of Modern Supertankers Facilitates the Transportation of Petroleum and Results in Environmental Catastrophe

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The Advent of Modern Supertankers Facilitates the Transportation of Petroleum and Results in Environmental Catastrophe

Overview

Easily the largest movable man-made objects ever constructed, supertankers were created and designed to meet society's enormous demand for petroleum. From fueling our cars to supplying heat to our homes, supertankers have made it possible for many nations to maintain high standards of living. Although supertankers have facilitated the transportation of enormous amounts of petroleum over thousands of miles, they have also caused some of the largest environmental disasters in history.

Background

The first oceangoing tanker ever constructed was the German-designed Glückauf. Launched in 1866 to transport petroleum from the United States to Europe, the Glückauf was 300 feet (91 m) long, 37 feet (11m) wide, carried 2,300 short tons (2,088 metric tons) of oil, and had a cruising speed of about nine knots (17 kph). Today, the Glückauf could easily fit into the hold of a supertanker, the largest of which is the Jahre Viking, which is over 1,500 feet (457 m) long, 227 feet (69 m) wide, and weighs over 565,000 deadweight tons. Indeed, ships this large are no longer even called "supertankers," as that term does not adequately capture their size. Instead, they are called "very large crude carriers" and even "ultra large crude carriers."

Some of the reasons that allowed tankers to grow to so large were, of course, technological advances in engineering and ship-building material. Though these technological advances made the construction of supertankers possible, the initial impetus for constructing them largely was political. The Suez Canal in Egypt, constructed in 1869 and enlarged periodically since then, is the primary trade route for ships and supertankers traveling from the oil-rich countries around the Red Sea to the Mediterranean Sea and points beyond. Although a convenient alternative to sailing around the Cape of Good Hope at the southern tip of Africa, the Suez Canal has, on a number of occasions, been closed due to armed conflicts. Such closures forced ships to travel the great distance around the Cape in order to get to the Mediterranean, Europe, and the Americas. However, because ship-builders no longer had to consider the Canal's dimensions, larger tankers could be built. By constructing larger tankers for the longer hauls, the additional cost and time it would take to sail around the Cape would be compensated by the fact that each tanker could carry more petroleum on each trip.

Perhaps the most important reason for increasing the size of tankers involved exploiting the so-called "square/cube rule." Assume, for example, that a tanker's hold is 4 feet (1.2 m) high, 4 feet wide, and 4 feet deep. Given these dimensions, the surface area of the hold is 96 square feet (9 square meters) (4 times 4 feet per side, times 6 sides) and the volume of the hold is 64 cubic feet (1.8 stere) (4 feet high, times 4 feet wide, times 4 feet deep). If the dimensions of the tanker's hold are doubled to 8 feet in height, width, and length, however, the surface area of the hold becomes 384 square feet and the volume becomes 512 cubic feet. In other words, by doubling the hold's dimensions, the surface area increases 4-fold, but the volume increases 8-fold. Thus, even though the cost of construction increases in terms of additional material required, the carrying capacity, and therefore potential revenue, is increased by a much larger proportion. Consequently, by building larger oil tankers, profit margins increase.

Impact

Although the development of the modern supertanker was a triumph for the shipbuilding industry and a boon to oil-producing nations, it has had a serious negative side-effect: modern supertankers involved in accidents have caused enormous damage to the environment. It was not very long after the first supertankers were constructed in the early-1960s that disaster struck in a way that the shipbuilding industry had not fully anticipated.

On March 18, 1967, the 118,285 dead-weight-ton tanker Torrey Canyon went aground on the Seven Stones rocks reef, off the coast of Cornwall, England, spilling nearly 35 million gallons (132,489,420 liters) of crude oil. The resulting oil slick was so vast that some of it spread across the entire English Channel all the way to France, covering over 260 square miles (673 square km). Although the spill took place in the ocean, it is worth noting that just one gallon (3.78 liters) of oil can ruin up to an estimated one million gallons (3785,412 liters) of fresh water—the equivalent of a year's supply of water for 50 people. Thus, a spill on the order of magnitude as the Torrey Canyon potentially could ruin over 35 trillion gallons (132 trillion liters) of fresh water, or equivalently, the drinking supply of 1,750,000,000 people for a year—nearly a third of Earth's population!

Since the Torrey Canyon, there have been even larger spills. On March 16, 1978, for example, the tanker Amoco Cadiz went aground near Portsall, France, spilling an estimated 65,000,000 gallons (246 million liters) of crude oil. An even larger spill resulted from the July 19, 1979, collision of the Atlantic Empress and the Aegean Captain off Trinidad and Tobago. It is estimated that an incredible 88,000,000 gallons (333 million liters) of crude oil was spilt in that accident.

Unfortunately, oil spills have continued to plague our oceans, the marine life that resides therein, and the humans whose lives are tied economically to the health of the sea. Perhaps the most infamous of recent oil spills is that of the Exxon Valdez. In the early morning hours of March 24, 1989, while her absentee captain lay asleep, the Exxon Valdez rammed into Bligh Reef in the middle of the pristine waters of Prince William Sound, Alaska. Though the grounding spilled only 11 million gallons (42 million liters) of oil (just one-fifth of the amount of oil she held), her grounding nevertheless resulted in the largest oil spill in United States history. Indeed, the spill polluted more than 1,300 miles (2,092 km) of Prince William Sound shoreline and severely degraded the economies of the surrounding fishing communities. It is no surprise that the impact of the spill was still being felt more than a decade later.

Despite the fact that the Exxon Corporation spent more than two billion dollars cleaning up the Sound, only two species—of dozens affected—have fully recovered from the effects of the spill. The Exxon Valdez Oil Spill Trustee Council, which is charged with administering the continuing clean-up efforts, has determined that contrary to initial beliefs that the oil would quickly degrade, much of the oil remains in the soil around the Sound. Thus, whenever a storm churns the Sound's water, more oil is drawn out of the soil and into the water, re-polluting the Sound. Even at seemingly infinitesimal levels, even one part of oil per billion parts of water is toxic enough to affect the reproductive cycle of salmon and herring. Consequently, the Sound likely will continue to suffer the adverse effects of the spill for decades to come. Unfortunately, what the long-term effects will be, and how and when they will manifest themselves, remains largely unknown.

It was not until the Exxon Valdez disaster that governments, especially the United States Government, began to closely study the long-term effects of such disasters. As a direct result of the Valdez grounding, the United States Congress passed the Oil Pollution Act of 1990, requiring ships transporting oil to have double hulls so as to decrease substantially the likelihood of similar disasters in the future. Essentially, the double hull acts as an additional barrier between external objects—such as rocks or other ships—and the oil carried by the tanker. For example, when the Exxon Valdez hit Bligh Reef, rocks from the reef penetrated more than 5 feet (1.5 m) into the ship. Had the Exxon Valdez been constructed with a double hull to protect its holds, however, no oil would have escaped, as there would have been 11 feet (3.35 m) separating the outer hull from the oil.

Largely because constructing tankers with double hulls increases construction costs, the oil-shipping industry avoided integrating them in tanker design. Given the enormous clean-up costs incurred by society and the long-term damage suffered by the environment after supertanker spills, requiring tankers to have this added level of security in order to prevent such spills seems not just acceptable but responsible. Indeed, this was Congress' reasoning for passing the Oil Pollution Act.

In addition to their potential for creating environmental disasters from oil spills, supertankers also contribute significantly to ocean noise pollution. The enormous engines and propellers used to move the tankers generate lowfrequency noise that can carry for miles across the ocean. As low-frequency hearing is believed to be the primary sense of whales, dolphins, and other marine species for finding food, avoiding predators, and locating mates, the noise from supertankers impedes the performance of these activities. Further, at close range, a powerful sound can cause tissue in the lungs, ears, or other parts of a marine animal's body to rupture and hemorrhage. Further away, the same sound can induce hearing loss in marine animals, causing them to swim off course, abandon their habitat, and become abnormally aggressive.

Ultimately, as long as the international demand for petroleum remains high, supertankers will continue to be constructed and likely will become larger. However, as Admiral J. W. Kime, Commandant of the U.S. Coast Guard, stated in testimony before Congress, "As long as there are ships at sea, there will be accidents. We cannot alter that fact. What we can strive to do, what our goal should be, is to insure that these accidents are as infrequent as possible, and that their consequences, to the ship, the personnel onboard, and to the environment, are as harmless as possible." By requiring supertankers to be constructed with double hulls and reduce their noise output, the goal of minimizing the impact of supertankers on the environment may be realized.

MARK H. ALLENBAUGH