A sacrificial impact-absorbing and energy-dissipating structure for protecting marine facilities from the destructive force of an accidental impact by a marine vessel is constructed from a plurality of inexpensive steel pipes or tubular members that are permanently secured together as by welding to form an open three-dimensional cubic framework of plastically deformable material. One or more of the tubular members forming the structure can optionally be filled with water, a rigid foam material and/or wooden elements that will provide additional energy-dissipation capabilities in the event that the containing tube is subjected to a deforming impact. Filler ports, discharge ports, pressure relief plugs, and valves can optionally be provided on one or more of the tubular members.