A gas transport vessel having a hull and a tank longitudinally received in the hull and method of constructing the tank within the hull. The vessel is designed to transport fluids, such as hydrogen or other gases and liquids. The tank has a plurality of layers that are unconnected to adjacent layers. The tank contacts the vessel at a top and bottom. The top connection, for example a connection to deck structure, supports the tank for preventing sagging. The tank may be substantially the length of the ship and located between a forward and a rearward bulkhead. Two tanks may placed adjacent one another separated by a longitudinal bulkhead. Each layer has a forward and rearward end cap constructed of multiple frusto-conical sections. A space is provided on sides of the tank to permit expansion. The tank is integral with ship structure, thereby providing additional strength to the vessel.