On board ships, cargo-related failure conditions are strongly dependent on cargo and lashing systems. This study presents a procedure for achieving an effective FE structural model of a container stack for carrying out the numerical simulations with the aim to define a numerical model that accurately simulates the actual deformation of a stack, making it as simple as possible in order to decrease the computational cost of the simulations. Using this model, a series of numerical analyses can be carried out for a huge amount of loading conditions obtained by non-linear numerical simulations of ship motions.