On September 4, 1993, at 1130 central daylight time, a Grob G-103, N153SS, sustained substantial damage in a hard landing following a cable break during a winch launch at the Silvercreek Gliderport, New Douglas, Illinois. Neither the certified flight instructor, nor the student pilot were injured. No flight plan was filed for the local instructional flight, and visual meteorological conditions prevailed at the time. The instructor reported the student was at the controls for the launch. He stated there was an apparent "cable break" about 20 feet AGL. Initially, the student lowered the nose, then tried to re-establish the climb angle. The instructor stated he took the controls at this point and moved the stick forward. He reported the glider struck the ground with the nose down. The instructor stated the double ring on the glider attachment point separated from the glider.