Holy cow... and never in shallow water it seems! For me, it's been catarafts.
Fortunately, last time - my brother was on the oars. We were on the Goodnews River, our first flyout float. The Goodnews is a gentle river mostly, with plenty of width and depth and very few rocks. Very few. We rocked and rocked with the oars. Tried poling off the bottom without success, then shifted weight and rocked some more. Thirty minutes I bet.
Two years ago, it was a friend in his heavily loaded 16-foot cat on the Upper Gulakana River -- high water and that one rock. When a cat is stuck, it's can really be stuck good. Always seems to be this one rock in deep water. What can you do? From another raft, we got a rope and some guys to shore and pulled...awhile.
This ever happen to anyone else?