Crude oil tankers have been built larger in response to increasing transportation demands and improvements in transportation efficiency after the Second World War (WW II).
Crude oil tankers come in various sizes, the biggest standard size being a Very Large Crude Carrier – or 'VLCC'. These tankers take up to 2 million barrels of crude oil per shipment, while the second largest size is the 'Suezmax' which takes around half of that amount and is the largest size ship that can sail through the Suez Canal fully laden.
The cost of a new VLCC has ranged from around USD 80 million to USD 160 million with capacity between 260,000 to 330,000 metric tons Deadweight (DWT). Vessels larger than this classifies as Ultra Large Crude Carrier (ULCC).
The size of a VLCC makes them more cost efficient for longer international trade routes between large ports that can physically accommodate their larger size. The smaller the vessel size, the more regional the trade routes become.
The cargo tanks on these vessels are separated into two or three blocks crosswise and about five blocks lengthwise, allowing the ship to transport different types of cargoes. In general, cargo is discharged offshore at a sea berth, connected by a pipeline to the terminal on shore.
Most of the tankers built in the 1970s were turbine driven. The turbine driven tankers had very poor fuel efficiency, but a wide technical range of engine load. As bunker prices rose substantially compared to freight rates, the much more fuel-efficient diesel engines were taken into use.
In 2005 those vessels were almost non-existing, and all the vessels of today’s fleet have modern diesel engines.
VLCCs (Very Large Crude Carriers)
