The pilot agreed to take the non-pilot rated aircraft owner and a passenger on a local flight. The pilot reported that during takeoff, he was not able to gain sufficient altitude to clear a fence off the departure end of the runway. The landing gear contacted the fence and the airplane continued forward until it contacted an embankment. The pilot stated he was not familiar with this particular airplane and airport, and that he should have had a greater safety margin on which to base his midfield go/no-go decision.