The hydroelastic behavior of some long beams floating on water is studied in this paper. Firstly, the hydroelastic responses of the beams in head waves, in displacement excitations and with vertical cliff are shown using a method proposed by Ohkusu and Nanba (1998). Next, vibrations of superstructures of the beam may give rise to group waves on the beam and may be damped. A relationship between the damping factor of the superstructures and bending rigidity of the beam is investigated. Finally, it is shown that the group velocity of the beam is larger than the phase velocity in shallow water.