The primary function of water tanks is to provide liquid to locations where it is required. Rectangular or square-shaped tanks, on the other hand, do not permit such liquid circulation and may even retain some liquid in their individual components. This is undesirable because it increases the tank's weight without providing any additional storage capacity. A circular tank, on the other hand, allows for even distribution of its contents throughout the container area. Tanks are usually round because this shape is easy to manufacture using modern engineering techniques. The wall thicknesses required to make a square tank would be very thin and therefore likely to fail under pressure. Even with thicker walls, a square tank would not be as efficient at storing fluid as a round one of the same size. There are times when it is necessary to store a liquid in a rectangular vessel. For example, this might be the case if you were making whiskey and needed several large barrels for your project. The proper way to fill these barrels is with a pipe that fits through the bung hole at one end and has a spout on the opposite side. When the barrel is full, the plug is removed from the other end of the pipe so that all of the whiskey can be drawn off.