Abstract : Among the whole various parts composing a rubble mound breakwater, armour layer represents the key component of the structure stability. It is composed either of quarry stones or of arti cial concrete armour units when the design wave conditions require heavy armour elements that careers may not able to provide. The development of the concrete armour unit performance has been the subject of numerous studies. The main concern was to propose optimizations leading to a better hydraulic stability thereby allowing low consumption of concrete and thus signi cant savings. The main objective of this thesis is to develop a new arti cial armor unit for rubble mound breakwaters. Work will contribute to develop methods for optimizing shapes of the armour units. The lesson collected at the end of the thesis will produce new forms more performing than those available today on the market. Based on hydraulic model tests, the results demonstrate the large hydraulic stability, in spite of overtopping remaining to be improved. In this study, other experimental tests were performed to investigate the velocity eld close to the armor layer and also the wave -induced loadings acting on one instrumented block. A new formula is proposed concerning velocity longitudinal in relation to run-up. It is shown that the in uence of the wave characteristics (breaking wave, impact) is a decisive parameter for the hydrodynamic coefficients.