In view of evaluating the dynamic crack arrest capability of metallic alloys potentially usable as structural materials for naval applications, impact tests were carried out on Kalthoff and Winkler type double notched structures. The metallic alloys at stake include a mild steel, a high strength steel and a high strength titanium alloy, exhibiting very different ductility values. Depending on the material and on the loading conditions in terms of initial temperature and impact velocity, one can observe shear- or tension-controlled crack propagation (Mode II vs Mode I), inducing partial or catastrophic failure, and for some cases adiabatic shear banding as precursor of the ultimate structural fracture.