Abstract
An aluminium alloy spherical tank for an LNG carrier is introduced as an example of the pressure vessel type tank.
On the first LNG carrier completed in 1958, stiffened prismatic tanks of aluminium alloy were installed. After her success LNG trade started. In the 1960's membrane tanks were developed. Stainless steel and invar were used for them. These tanks were welcomed by the shipbuilders around 1970.
In the midst of the industrial situation, a spherical tank was developed. The LNG load was supported by the membrane stress of the unstiffened tank skin. After an LNG carrier of this type was firstly completed in 1973, she proved to be most reliable and economical. Since then a tank competing with this did not appear.
