Within the universe of tranporting people and goods, ships play an essential role as mass transport vehicles. Like other machines and mechanical elements, shops are subjectes to different stresses in their respective structures. Such effors may be the cause of a possible failure, and therefore, their knowledge is of fundamental importance for project design and preventive maintenance on existing ships. For all these aspects, it is extremely interesting to know to model these efforts suffered by the ship. However, the construction of this model can be complex. Ships usually have extremely complex structures and geometries, so representing them within a model may not be a trivial task. Knowing this, this work proposes a model to represent the ship dynamics through the simple and know beam theory. First the homogeneous problem is solved, analytical solutions are found for the vibration modes that are compared with numerical approximations of them. Those numerical approximations are obtained with the help of the finite element discretization technique. We observe the influence of the number of elements used in th discretization in the representation of the different modes, since the more complex the movement of the mode (higher natural frequency) the more elements are required to get an error of less than 1 percent. After this first part, we pass on the study of forced responses. In addition to finite element discretization, we use the Runge-Kutta numerical integration method to solve te differential equations in time. We note that it is possibel to determine the number of elements required to represent the dynamics of the forced beam correctly. Knowing the highest frequency excited by forcin we can determine how many elements are needed to represent the most complex mode excited by external force. We analyza that this choice of number of elements is crucial, since when we choose fewer elements than necessary we risk losing information about the dynamic response of the beam. On the other hand, when you choose too many elements the calculation time increases considerably (it can increase by 1 hour from 30 to 50 elements for example) Without gain in accuracy (differences betwen the same approcimations with 30 and 50 elements is in the order of 10 (-5) percent.