I don't know if these can be "hammered" into the ground by hand or not. I saw one of these down in Maryland being "driven" into the ground....VERY sandy soil not far from the shore (200 yards?) of Chesapeake Bay.
The pipe was about 8 feet long. One fellow held the pipe verticle while another fellow with a back hoe
"Leaned On" the top of the pipe with the small bucket, essentially pressing the pipe into the ground. It went right in in one stroke.
NB