Abstract: An independent vessel tank system for storing liquid gas on a vessel has a first tank member, a second, cylindrical tank member connected to the first tank member, a third tank member connected to the second tank member, wherein the first, second and third tank members provide a tank device for the liquid gas, a first supporting device provided between the third tank member and a hull of the vessel, for supporting the weight of the tank device, and a second supporting device at least partially provided along a periphery of the tank device, for supporting the tank device to the hull of the vessel. The second supporting device is flexible in a first direction parallel to the centre axis of the tank device, and flexible in a second direction perpendicular to the periphery of the tank device.