LNG carrier is a ship that transports liquefied natural gas. The main component of liquefied natural gas is about 90% of methane, its specific gravity is about 0.46, and the temperature at which it changes from gas to liquid is about -161.5oC, and the volume at that time decreases to 1/600. In high pressure and cryogenic conditions, the brittleness (breaking property) of general metals increases significantly. To avoid this, LNG carrier cargo holds (Independent tank category) should be made of special steel 9%-Ni, stainless steel, aluminum alloy, High-Mn, etc. SSIHI specialized in small and mid scale LNGC construction including conversion of existing vessel with Type B and C cargo tank.