Ship to ship interaction is a common phenomenon that has already led to many accidents at sea. The consequences of interaction differ depending on the way the two ships meet and on the parameters of the interaction. Among the many parameters, we cannot ignore the bank effect and the influence of the shallow waters. Due to bank effect the sway force and yaw moment are reduced, but the surge force increases. On shallow waters a moving ship experiences ships' squat, which is made even worse when interacting with another ship. Many methods of calculating the force of the interaction have been created, most empirical formulae calculate the interaction on a moored vessel, however for other tipes of interaction teoretical formulae are more common. Neither of these methods are accurate enough for their results to be used with certainty. Ship-handling simulators come close to the true forces of interaction.