Experimental study of the damage energy is a reproduction of the GFRP vessels’ slamming in the sea. The investigation was carried out to the laboratories by the construction of two types of GFRP panels: viscoelastic and non- viscoelastic modified. Through a bending test, the data collection was developed to get the measurement of the variables in key points. The obtained results showed an expected behavior because the modified specimens were able to spread the force induced from the center to the edges. Besides, the damage energy in the modified panels return in bigger amounts than the unmodified. Flexibility demonstrated a higher rate of increase in the unmodified panels, indicating that the viscoelastic layer contributed to the stiffness increment in the modified panel. In conclusion, viscoelastic materials help to dissipate the energy absorbed by the structure, elongating the lifetime. Also, this study expands the basic knowledge of viscoelastic materials’ behavior in the GFRP planing hull vessels.