An oil tanker is a vehicle or vessel specifically designed for the transportation of crude oil, refined petroleum products, or other oil - based substances. Land - based oil tankers are trucks or trailers with large - capacity tanks, while maritime oil tankers are massive ships used for long - distance ocean transport. The tanks of oil tankers are constructed from materials like steel or stainless steel to withstand the pressures and corrosive effects of oil. They are equipped with pumping systems, valves, and hoses for loading, transporting, and unloading oil. Safety features, including double - hulls, emergency shut - off valves, and leak - detection systems, are standard to prevent spills and ensure the safe transit of oil, which is crucial for the global energy supply.