Beidou Star

An LNG carrier is a ship built around insulated cargo tanks that hold liquefied gas at minus 162 degrees, with an engine able to burn the cargo vapour that inevitably boils off during the voyage.

Cargo containment is the system that holds LNG at minus 162 degrees inside a ship, and it comes in two families: membranes, which are thin barriers supported by the hull, and free-standing tanks, which carry their own load.

LNG carriers fall into recognised size classes running from small-scale vessels under 30,000 cubic metres, through the 174,000 cubic metre conventional standard, to the 266,000 cubic metre Q-Max ships built for Qatar.

Boil-off is the small fraction of an LNG cargo that evaporates each day as heat leaks into the tanks, and it is what keeps the rest of the cargo cold.