LNG carrier

An LNG carrier is a gas tanker purpose-built to transport liquefied natural gas (LNG) at atmospheric pressure and a cargo temperature of approximately −163 °C. Containment systems fall into two principal types: membrane (Gaztransport & Technigaz Mark III or NO96 systems, where a thin metallic membrane bears the cargo) and independent Moss spherical tanks (MOSS Maritime Type B), where self-supporting aluminium spheres protrude above the main deck. Typical capacities range from 125 000 m³ for older vessels to 266 000 m³ for Q-flex and Q-max designs built for the Qatari LNG trade. Propulsion has evolved substantially. Steam turbine plant dominated until the mid-2000s; subsequent newbuildings adopted dual-fuel diesel-electric (DFDE) and tri-fuel diesel-electric (TFDE) configurations that burn boil-off gas (BOG) efficiently. Modern designs use two-stroke low-pressure X-DF (WinGD) or ME-GA (MAN ES) engines achieving superior fuel economy. Boil-off management and reliquefaction plants are integral to commercial operations. All LNG carriers are classed under the International Gas Carrier (IGC) Code, made mandatory under SOLAS Chapter VII, which prescribes standards for hull design, cargo containment, instrumentation, fire fighting, and crew safety. The IGF Code governs vessels using LNG as bunker fuel. See also the /reference/ship-types overview for the broader gas carrier sector.