Before landing, the pilot circled the 2,500 feet landing strip several times to check on surface conditions and decide oh his landing direction. There was no wind and after observing another aircraft make a landing into the south east, the pilot made a left circuit and approached in the same direction. The approach path was steeper than normal and made at a speed in excess of that recommended for approach at the existing aircraft weight. After floating for some distance, the aircraft did not decelerate as quickly as he expected. When he became aware that the aircraft was not going to stop within the confines of the strip he turned to starboard slightly, towards what appeared to be an extension of the strip. It became obvious that this area also was inadequate and the pilot then turned the aircraft to port. As the boundary of the cleared area was reached, and at a speed of some 10 knots, the starboard wheel entered a depression and the undercarriage unit was torn from the aircraft.