Gastankers

Gastankers are specialized ships designed to transport liquefied gases in bulk. The term covers LNG carriers and LPG carriers, which carry liquefied natural gas and liquefied petroleum gases, respectively. Both require advanced insulation, robust containment systems, and careful handling of cryogenic cargo.

LNG carriers store cargo at cryogenic temperatures and use either membrane containment systems (developed by industry groups like Gaztransport & Technigaz) or Moss spherical tanks. LPG carriers transport LPG such as propane and butane and use spherical or prismatic insulated tanks that can be designed for refrigerated or pressurized operation, depending on the cargo. Ships are double-hull vessels with dedicated cargo tanks, cargo handling systems, and boil-off gas management. Boil-off gas—the small amount of cargo that vaporizes—may be reliquefied on board or used as fuel for propulsion and cargo pumps. Safety systems include inert gas, gas detection, emergency shutdown, and highly trained crews.

Operations typically involve loading at specialized gas terminals, transporting across global routes, and unloading at terminals equipped to regasify LNG or dispense LPG. In contrast to other tanker types, gastankers require cryogenic and hazardous cargo handling expertise, strict maintenance of insulation, and careful route planning to minimize boil-off and emissions.

Environmental considerations include methane slip from boil-off and pressure relief, with ongoing improvements in energy efficiency and terminal handling. The development of containment technologies and standardized safety practices has enabled the growth of global LNG and LPG trade.