Cargo Containment System
A Cargo Containment System (CCS) is the complete arrangement that holds the liquefied gas cargo on an LNG or LPG carrier — the cargo tanks, their insulation, and the secondary barrier that contains any leakage — keeping the extremely cold cargo isolated from the steel hull, which would become brittle at those temperatures.
The two main families are membrane systems, where a thin flexible barrier supported by insulation lines the hold, and independent (self-supporting) tanks, of which the spherical Moss tank is the best-known. The choice of containment system shapes the ship appearance, capacity, boil-off rate and cost.
The containment system is the heart of a gas carrier: it is what safely holds a cargo cold enough to embrittle steel, keeps boil-off low, and protects the hull. Its type determines the ship capacity, efficiency and cost, making it the defining design choice for the vessel.
What is the difference between membrane and Moss containment?
Membrane systems use a thin barrier supported by insulation built into the hull structure; Moss systems use large independent spherical tanks that sit in the hull. Both keep the cold cargo isolated from the hull, with different trade-offs in capacity, boil-off and cost.