Look at those metal rings closely. Mine are split on one of the elongated sides. Take two pairs of pliers and hold the clip with one and twist at where the loop ends join with the other pair and they will bend so that you can take out the curtain. When replaced, just ben the two ends back into alignment.
I'm on a coffee break while on three day outing, so ran out and looked at the metal rings... They do have the seam PSW mentioned. Also took a look at the "rod" and it is secured with screws.
There are two screws that could be removed, allowing the metal hooks to slide right off, or so it seems.
Thank you so much, hallock5 and PSW, your input has made my day!
I just took two shower curtains and overlapped them by two feet or so. The lightweight curtains sure dry faster. Mine are probably the non vinyl that goes on the outside of showers. Works for me.