Abstract: Passive apparatus for absorbing the kinetic energy of a collision to prot an underwater structure from damage in a collision which includes a ring suspended by a ring support system so that the ring is positioned between the structure and the expected path of potentially impacting objects. The ring support system includes eight rigid rods which have one end coupled to one of four symmetrically disposed supporting pylons by spherical sleeve bushings and their other end coupled by spherical rod ends to one of four standoff members that are fixed to the top surface of the ring at equal intervals around its circumference. A shock absorber is coupled between each supporting pylon and the ring midway between standoff members by spherical rod ends. The dimensions of the rigid rods and their attachment points to the supporting pylon and the ring are chosen so that the ring may pivot on the rods against the resistance of the shock absorbers in response to an impact, but cannot strike the enclosed object.