Abstract: The tank and baffle system comprises a tank for transporting liquids, having a plurality of baffles for controlling surges and excess liquid movement produced by movement of the tank. The present invention is particularly useful where there is a large ratio of tank width to tank support and lateral bending loads may be in excess of longitudinal bending. The baffles are rigidly secured to a tunnel structure that spans longitudinally from the front to the rear of the tank, and forms a continuous structure in both longitudinal and transverse directions. A further aspect of the invention is the use of chamfered corners on the baffle plates to provide fluid communication between chambers of the tank, as well as to reduce surging of the liquid contents and reduce or eliminate joint fatigue. Access ports in the baffles that are covered by access covers during use are another aspect of the invention.