VLCC or Very Large Crude Carriers and ULCC or Ultra Large Crude Carriers are the largest operating cargo vessels in the world. With a size in excess of 250,000 Dead Weight Tonnage (DWT), these giant ships are capable of carrying huge amount of crude oil in a single trip. Known as Supertankers, these vessels are primarily used for long-haul crude transportation from the Persian Gulf to countries in Europe, Asia and North America.

VLCC have a size ranging between 180,000 to 320,000 DWT. They are capable of passing through the Suez Canal in Egypt, and as a result are used extensively around the North Sea, Mediterranean and West Africa. VLCC are very large shipping vessels with dimensions of up to 470 m (1,540 ft) in length, beam of up to 60 m (200 ft) and draught of up to 20 m (66 ft). But the standard dimensions of these ships range between 300 to 330 meters in length, 58 meters breath and 31 meters in depth. They are known for their flexibility in using terminals and can operate in ports with some depth limitations.