A Crow brand TUFNOL dolly employed to protect piles from the repeated hammer blows of a pile driver. Each blow delivers a maximum explosion force of 70 tons, and the striking rate of the hammer shown on the left, under which this dolly served, is fifty blows per minute. Greenheart dollies previously used had had to be replaced after short working periods, so adding to costs and operational time losses. The TUFNOL dolly is shown here after nine months of life.