Patrick Matiwane (who worked for me for a few years) places a car tire into a barrel before sinking it. By placing first some padding like old pillows into the drum to dampen the pan head, and then some tires which were held in place with some screws driven straight through the side of the barrel, it was possible to (A) reduce the amount of noise the sinking process generated, and (B) stop the drum moving around while it was being hammered on.

Pan Master, Old Power Station, Grahamstown, South Africa -- 1995