Supertankers

Supertanker is a term used to describe the largest classes of merchant oil tankers used to transport crude oil and refined products. In shipping industry parlance, the term typically encompasses ultra large crude carriers (ULCCs) and, less strictly, very large crude carriers (VLCCs). ULCCs are defined as ships with deadweight tonnage (DWT) exceeding about 320,000; VLCCs range from roughly 200,000 to 320,000 DWT. Depending on oil density, these ships can carry several million barrels of crude on a single voyage.

Most supertankers are built with double hulls and multiple segregated cargo tanks to minimize spill risk and to meet safety regulations. They are among the longest and widest merchant ships, often exceeding 300 meters in length and 50 meters in beam, with crews typically around 25–40 people depending on size and automation. They require deep-water berths and long, straight sea routes to be economical, and their navigation plans are sensitive to canal restrictions, weather, and piracy considerations.

Key examples include the Seawise Giant, later known as Jahre Viking and Knock Nevis, which at construction was the largest ship ever built. It remained in service in various forms until scrapped in 2009. Other large tankers operate in the VLCC and ULCC classes on global crude routes, especially from the Middle East to Asia and Europe.

Environmental and regulatory considerations shape their operation. International conventions such as MARPOL and SOLAS govern safety and pollution prevention, while double-hull requirements in many jurisdictions increased construction costs. The economics of supertankers are tied to global oil demand, freight rates, and fleet utilization, with cycles of expansion and scrapping influencing their share of the cargo market.