"riverman" wrote in message
...

Absolutely. In the river running world, its called 'foot entrapment' and
is the single most dangerous aspect of being out of your boat in moving
water. The pressure of water is something like one ton of pressure per
square foot per ten mph. So if you are in a 14 mph current and get your
foot trapped, a comealong wouldn't your head up, life jacket or not. Cars
get swept away in 10 mph streams that are less than 2 feet deep. Getting
things (boats, cars, bodies) off of rocks when they are entrapped is an
artform. I've pulled well over 200 boats free, fortunately never had to
get a body out. The ones I have come closest to having to recover came
free during the night while we were planning recoveries, when the water
levels dropped.

Your body is not actually pinned against the bottom: its more like a flag
flapping in a strong breeze. But the shape of your ankle and foot is a lot
like a fishhook, and once its jammed under something, its very difficult
to get it back upstream to get it out. The common practice is exactly like
how you get an embedded hook out of your palm; you run a rope across the
river, downstream of the body. Then you walk back upstream until you have
the rope hooked under the body. You work it down until the rope is down
near the foot, then you pull back against the current until the body
'unhooks' the rock and pops free. Virtually all foot entrapments occur in
water about 2-3 feet deep. Deeper than that, and they float over the
rocks. Shallower than that, they tend to bump along on their butts and
tumble along until they get to deeper water.

The rule of thumb is to never stand up in water deeper than your knees, as
that is how deep the water can be while you hold your head up with your
arms. Of course, we wade water deeper than that all the time, and I don't
think most of us truly appreciate how easily even a 2-3 mph current could
hold you under if your foot is entrapped. We had a thread about this a
short while ago.

If you fall over, get your feet UP, lay as flat as you possibly can, and
swim out of the current, or at least over to where you can hold on to
something while you 'feel around' with your feet to get a purchase. But
treat the bottom like a minefield.

--riverman

A high school kid died in the Nantahala river in North Carolina four or five
years ago. The situation was just as you described. I don't think the water
was even two feet deep. It probably happens more often than that, but I'm
familiar with that one because someone I know was a rafting guide on the
river at that time. I think about that every time I wade those freestone
streams.
Bob