Lng tanker and method for marine transportation of lng

Abstract

An LNG tanker is provided which can have larger tank capacity for its hull size, be easily built, and reduce the sloshing in membrane type tanks during a heavy weather. The foremost LNG tank is made in a spherical independent type ( 24 ), and each of subsequent tanks is made in membrane type ( 26 ). The membrane type of tank has heat insulating material on the inner shell of a double hull with its surface covered by membranes. During the voyage, the liquid cargo (LNG) in the spherical independent type tank is transferred to membrane type of tanks, thereby to compensate LNG losses caused by generation of boil-off gas in the membrane type tanks.

1 . A liquefied natural gas (LNG) carrying ship comprising:
 a plurality of LNG tanks on board said ship, including a foremost tank and a plurality of subsequent tanks; and   said foremost tank being made in a spherical free-standing type and said subsequent tanks each being made in a membrane type.   
   
   
       2 . A method for marine transporting LNG comprising:
 providing two different types of LNG tanks onboard, one being of a spherical free-standing type of tank, and the other being of a membrane type of tank; and   transferring LNG from said spherical free-standing type of tank to said membrane type of tank so as to compensate LNG losses caused by generation of boil-off gas in said membrane tank during a voyage.