When I was going to school in the late 70's we toured the archeology lab at Cal State Northridge. The guide pointed out a section of pre-45 steel ship's propell

When I was going to school in the late 70's we toured the archeology lab at Cal State Northridge. The guide pointed out a section of pre-45 steel ship's propeller shaft (about 1.5 - 2' in diameter, hole through the center) that was used for radiocarbon dating.