How It Works-Amazing Vehicles

Pump room

Supertankers are equipped with three or

four steam-powered centrifugal pumps

that suck oil from the cargo tanks and

pump it ashore at rates of 4,000 cubic

metres (141,259 cubic feet) an hour.

Engine room

The main engine

is a two-stroke

reversible diesel

engine packing

over 20,000 boiler

horsepower to

turn a bronze

propeller that is

more than 8m

(26ft) across.

Crew quarters

Supertankers are

manned by skeleton

crews of captains,

officers, engineers,

pumpmen, cooks,

deckhands and more

who live on the ships

for months at a time.

Navigation and

communications

Modern supertankers are

equipped with satellite

communication towers, GPS

navigation systems and

advanced radar stations that

show the identity and courses

of nearby vessels.

ON THE

MAP

Top oil producers*

1 Country: Russia

Barrels per day: 9.93m

2 Country: Saudi Arabia

Barrels per day: 9.76m

3 Country: United States

Barrels per day: 9.14m

4 Country: Iran

Barrels per day: 4.17m

5 Country: China

Barrels per day: 4.00m

*Source: US Energy

Information Administration

Internal-combustion tankers

A lfred Nobel’s brothers, Ludv ig and

Robert, were oil tanker innovators. The

Vandal was their first diesel-electric ship,

powered by three 120hp diesel motors.

Wartime refuelling

The USS Maumee was the first

large oil tanker used to refuel

destroyers on their long Atlantic

voyage from America to the UK.

First supertanker

The Japanese-built SS

Universe Apollo was the

first oil tanker to exceed

100,000 deadweight tons.

1903 1915 1958

© A lex Pang

Oil tanker

classifi cation

Oil tankers come in all sizes. Here we

explain the differences and what it

takes to qualify as a supertanker

Medium-range tanker

<44,999 DWT (deadweight tons)

According to a system developed by Shell Oil called the average

freight weight assessment, oil tankers are classifi ed by the

maximum amount of deadweight tons (DWT) they can carr y.

Medium-range tankers handle up to 44,999 DWT and include

the Seaway ma x class of tankers, the largest vessels that can

pass from the interior Great Lakes of the US-Canadian border to

the Atlantic Ocean v ia the St Law rence Seaway.

Long-range tanker 2 (LR2)

<160,000 DWT

Some LR2 tankers are t w ice as large as the heav iest LR1s,

reaching a maximum weight of 160,000 DWT. Smaller tankers in

the LR2 class roam the waters of shallower sea basins like the

North Sea, Black Sea and the Caribbean. The largest LR2s still

fl oat shallow enough to pass through the Suez Canal, thus

avoiding the long journey around the southern tip of Africa.

Long-range tanker 1 (LR1)

45,000-79,000 DWT

Tankers classifi ed as LR1 can carr y bet ween 45,000 and 79,000

DWT, which may be small on a supertanker scale, however LR1

tankers do have their advantages. For example, no tanker larger

than an LR1 can squeeze through the narrow locks of the

Panama Canal, which can shave many miles off a journey.

Very large crude carrier (VLCC)

<319,999 DWT

From the VLCC class up is offi cially supertanker territory. VLCCs

weigh in at a maximum 319,999 DWT. VLCCs are also know n as

Malaccama x craft, because they are the largest tankers that can

fi t through the Strait of Malacca – a 25-metre (82-foot)-deep pass

bet ween Malaysia and Sumatra – the most direct sea route from

the oil-rich Middle East to oil-hungry China.

Ultra large crude carrier (ULCC)

<500,000 DWT

These gargantuan vessels – more like small, fl oating nation-

states – are the monsters of the supertanker world, w ith a

maximum carr y ing capacit y of 500,000 DWT. The t y pical ULCC

can transport over 3 million barrels of oil, more than the

combined daily energy usage of England and Spain. Most ULCCs

are too big to fi t through canals, so they must take the scenic

route around the southern tips of A frica and South A merica.

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DID YOU KNOW? Supertankers aren’t built for agility; it can take 15 minutes for one to shift from full forward to full reverse