Abstract: Vessel comprising a number of composite storage tanks for transport of compressed natural gas (CNG) or a combination of gas and liquid, which tanks have an elongated, cylindrical intermediate section and a lower end and an upper end, the tanks being arranged side-by-side vertically standing in the vessel, distinguished in that the hull, the bulkheads and the deck of the vessel form a closed space enveloping all tanks except from the upper end of each tank or selected tanks, for which tanks the upper end extends sealingly out of the closed space, all feed-throughs in the tanks with couplings for loading and unloading are outside of the closed space, at the upper end of the tanks, and the tanks are supported such that each tank can expand or contract freely within the operating range of the tanks with respect to pressure and temperature.