There is growing evidence that wave records may under certain conditions have occurrence of extreme waves. The occurrences of dangerous wave conditions in coastal waters may possibly be explained by linear focusing on the refraction by bottom topography, current gradients or even reflection from land. Well documented in that respect are the giant waves sometimes found in the Agulhas current on the eastern coast of South Africa. It seems, however, that this kind of freak or rogue waves exist even in the open sea far away from strong current gradients. We perform experimental investigations of breather-type solutions of the nonlinear Schrödinger equation, which are candidates describing rogue waves within the context of nonlinear theory. The aim of the analysis is to predict the occurrence of large amplitude wave wich appear from nowhere and disappear without a trace.