Vessels specialised in the transport of crude oil. Large crude oil tankers can be divided in 4 classes:

1. Ultra Large Crude Carrier ( ULCC)

ULCC or Ultra Large Crude Carriers are the largest shipping vessels in the world with a size ranging between 320, 000 to 500, 000 DWT. Due to their mammoth size, they need custom built terminals. As a result they serve a limited number of ports with adequate facilities to accommodate them. They are primarily used for very long distance crude oil transportation from the Persian Gulf to Europe, Asia and North America. ULCC are the largest shipping vessels being built in the world with standard dimensions of 415 meters length, 63 meters width and 35 meters draught.

2. Very Large Crude Carrier ( VLCC)

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.

3. Suezmax

Named after the famous Suez Canal, Suezmax are medium to large-sized ships with a deadweight tonnage ( DWT) between 120, 000 to 200, 000. They are the largest marine vessels that meet the restrictions of the Suez, and are capable of transiting the canal in a laden condition. Prior to 1967, the size of suezmax vessels was restricted to 80, 000 DWT, but the maximum was increased to 150, 000 DWT in 1975. After the further deepening of the Suez Canal from 18 m ( 60 ft) to 20. 1 m ( 66 ft) in 2009, a suezmax of up to 200, 000 DWT or even more can easily pass through it. Future plans of further deepening the canal’s draft to 21. 3 m ( 70 ft) may lead to redefining of suezmax vessels’ specifications in the coming years.

4. Aframax

Aframax is a medium-sized crude tanker with a dead weight tonnage ( DWT) ranging between 80,000 and 120, 000. The tanker derives its name from AFRA which stands for Average Freight Rate Assessment. AFRA system was created in 1954 by Shell Oil to standardise contract terms.

Though relatively smaller than Very Large Crude Containers ( VLCC) and the Ultra Large Crude Containers ( ULCC), the tanker has a cargo carrying capacity between 70, 000 and 100, 000 metric tonnes. The average cargo carrying capacity of Aframax is approximately 750, 000 barrels.

Due to their favorable size, Aframax tankers can serve most ports in the world. These vessels serve regions which do not have very large ports or offshore oil terminals to accommodate very large crude carriers and ultra large crude carriers. Aframax tankers are just perfect for short to medium haul crude oil transportation.

Aframax tankers are extensively used in areas of lower crude oil production such as in Non- OPEC countries which lack large harbors and canals to accommodate VLCC and ULCC class of tankers. Their main areas of operations include South American oil cargo exports to the US Gulf region through the Caribbean, North African exports to Southern Europe through Mediterranean, exports from former Soviet Union Republics to Northern Europe through the Black Sea and the North Sea, and South East Asian exports to the Far East. As Aframax vessels are mainly used in transporting crude oil, they are sometimes called ‘dirty tankers’.