The design of a water ballast control system for an offshore platform located in the Venice lagoon is being considered. The primary aim of the system is to maintain balance in roll and pitch, even in the presence of external disturbances, such as waves, wind or static imbalances on the platform. The structure's balancing action is generated by water tanks that distribute masses of ballast water, generating a rotational moment which returns the structure to the desired position. Managing and allocating the water masses is the ultimate goal of the control system. First, a hydrostatic balance study of the structure is conducted to determine the required ballast water amount, optimal tank size and position for meeting hydrostatic balance requirements.