
Bunker fuel is the fuel oil/gas delivered to ships of all states that are engaged in international navigation, which may take place via sea, on inland lakes & waterways, and in coastal waters. The two major bunker fuels used in the marine industry are distillates and residual fuel oils. Marine distillates are divided into marine gas oil (MGO) and marine diesel oil (MDO). Marine gas oils are used in small, highly rated diesel engines, which are found in many types of ships. Residual fuel oil, also known as heavy fuel oil (HFO), is the highest viscosity oil fuel. The most commonly used heavy fuel oils at sea are the intermediate fuel oils, namely, IFO 180 and IFO 380.