The paper summarises experiments and finite element simulations of a square steel plate laterally impacted by a rigid hemispherical indenter. The plastic response until failure is evaluated in a quasi-static and dynamic manner, so that to investigate the importance of the material strain rate for the material characterisation in numerical analyses of similar plate structural components used in the shipbuilding and marine offshore industry. For the purpose, quasi-static and dynamic tensile tests are performed, aiming at defining accurately the material nonlinearities in the simulations of the fully instrumented quasi-static and dynamic impact test. Details of both experiments and simulations are provided, together with a discussion on the Cowper–Symonds material strain rate model, commonly selected for the analysis of ship–ship collisions and/or ship collisions with offshore platforms.