S4Simon - thanks for the input. It seems like a very big job to me as well. Not sure if I am willing to attempt it. I certainly don't want to pay that much to a shop for a boat this old.
Nasher - the seams along the length of the boat are overlapped, but at the stern, as you surmised, they appear to be just pressed together. I think it was done this way because the tubes are tapered and the overlapped seams would not bend (guessing). The catastrophic failure was actually at one of these pressed together seams.
I think it is time to give up on it. Anyone interested in the original hard-parts from the boat? I have the seats, collapsable oars, and the stern, all made from wood. The boat itself is destined for the trash.