Low-head dam drowning on Yakima River, WA State
 

Bob P wrote:

In desperate circumstances, you're better off taking off the PFD and
diving down to follow the bottom current out of the backwash. Few
people who get in (low-head-dam) trouble have the knowledge or composure
to make that radical move, however.

I've given that some thought. Over the years, this option seems to have
surfaced on RBP a couple of times. My main concern would be what happens
after you get out of the hydrolic, and what would happen if taking off
your PFD wouldn't get you out. I'm fairly ambiguous about whether or not
that would be a smart thing to do. It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if needed.


--
Wilko van den Bergh wilkoa t)dse(d o tnl
Eindhoven The Netherlands Europe
---Look at the possibilities, don't worry about the limitations.---
http://kayaker.nl/

Low-head dam drowning on Yakima River, WA State
 

"Wilko" wrote in message
...
Bob P wrote:

In desperate circumstances, you're better off taking off the PFD and
diving down to follow the bottom current out of the backwash. Few people
who get in (low-head-dam) trouble have the knowledge or composure to make
that radical move, however.

I've given that some thought. Over the years, this option seems to have
surfaced on RBP a couple of times. My main concern would be what happens
after you get out of the hydrolic, and what would happen if taking off
your PFD wouldn't get you out. I'm fairly ambiguous about whether or not
that would be a smart thing to do. It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if needed.

This boondoggle arises all the time.

As far as my experience goes, the old "take off your PFD and flush out the
bottom of the hole" strategy is an urban legend. Everyone knows the rule,
but afaik, no one knows anyone who has actually had to do it. Its in the
same legendary category as putting maggots in an open wound to stymie
gangrene from forming, or as using soldier ants as stitches to close a
wound, or to use a swiss army knife to cut an oar in half to extricate it
from your leg. Sounds good in theory, but in practice you are just never in
that exact type of situation, or else there are other complicating factors
that prevent it from really being a good strategy.

I think if you were actually trapped in a hole with sharp enough edges to
keep you in, you would be underwater and tossed around so much that you
would have no idea which way 'down' was, let alone how to crawl along the
bottom. Also, once you shed your pfd, the force of the water would almost
certainly prevent you from using the rocks along the bottom anyway, as you'd
be plastered down there at best, or slammed among them at worst. As Wilko
points out, even if it DID work, you'd then be downstream without a PFD,
pretty beat up and completely out of breath. Also, in the aerated water
behind the pourover, you would have less floatation than normal and would
have NO chance to catch a breath, so you'd be more likely to drown without a
pfd than with it on.

I think it'd be very interesting to hear some statistics about people who
have gone over low-head dams with and without PFDs, and get some statistics
of who actually has washed out vs who has drowned. I'd bet dollars to
doughnuts that the majority of people without PFDs drown, and the majority
of people with them flush out.

No, unless I hear some pretty definitive stories from folks who have had to
actually do this, and who can verify that their PFD remained in the hole
indefinately afterwards (in other words, it was a true keeper hole), I
choose to believe that this is a poorly thought out legendary old wives tale
that impressess newbies.

--riverman

Low-head dam drowning on Yakima River, WA State
 

riverman wrote:


I think if you were actually trapped in a hole with sharp enough edges to
keep you in, you would be underwater and tossed around so much that you
would have no idea which way 'down' was, let alone how to crawl along the
bottom.

That's correct. Spatial disorientation would be but one facet of the
experience that makes a low-head tailwater hydraulic a "drowning
machine". Visibility is bad to non-existent, bubbles go in all
directions, and the current is quite deceptive. I know a guy who went
diving in a similar current, looking for lost anchors. He did this and
several similar crazy things in his younger years, and is quite lucky to
have survived many of them. He's the only person I know who was in such
a current and lived to talk about it, he had SCUBA gear and advanced
training, he was quite impressed with the power of the hydraulic and
says he couldn't see how anyone without all the equipment could have
gotten out of it.

Our Dive/Rescue team had one of these hydraulics in our jurisdiction and
we used to really worry about a potential rescue or recovery there until
the Army Corps of Engineers solved our problem by rebuilding the
structure in question to eliminate the low-head dam.

Low-head dam drowning on Yakima River, WA State
 

Wilko wrote:

Bob P wrote:
In desperate circumstances, you're better off taking off the PFD and
diving down to follow the bottom current out of the backwash. Few
people who get in (low-head-dam) trouble have the knowledge or composure
to make that radical move, however.

I've given that some thought. Over the years, this option seems to have
surfaced on RBP a couple of times. My main concern would be what happens
after you get out of the hydrolic, and what would happen if taking off
your PFD wouldn't get you out. I'm fairly ambiguous about whether or not
that would be a smart thing to do. It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if needed.

I suspect it's an urban legend. Perhaps all the swimmers found dead
without a PFD attempted to do it. Or their PFDs weren't tight enough.
Here's a story of somebody who did it and survived:

http://www.ptone.com/Kayak/RF/

Low-head dam drowning on Yakima River, WA State
 

riverman wrote:
"Wilko" wrote in message
...
Bob P wrote:
In desperate circumstances, you're better off taking off the PFD and
diving down to follow the bottom current out of the backwash. Few people
who get in (low-head-dam) trouble have the knowledge or composure to make
that radical move, however.
I've given that some thought. Over the years, this option seems to have
surfaced on RBP a couple of times. My main concern would be what happens
after you get out of the hydrolic, and what would happen if taking off
your PFD wouldn't get you out. I'm fairly ambiguous about whether or not
that would be a smart thing to do. It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if needed.

This boondoggle arises all the time.

As far as my experience goes, the old "take off your PFD and flush out the
bottom of the hole" strategy is an urban legend. Everyone knows the rule,
but afaik, no one knows anyone who has actually had to do it. Its in the
same legendary category as putting maggots in an open wound to stymie
gangrene from forming, ...

Actually, maggots are now occasionally used in hospitals to eat dead flesh.


I think if you were actually trapped in a hole with sharp enough edges to
keep you in, you would be underwater and tossed around so much that you
would have no idea which way 'down' was, let alone how to crawl along the
bottom. Also, once you shed your pfd, the force of the water would almost
certainly prevent you from using the rocks along the bottom anyway, as you'd
be plastered down there at best, or slammed among them at worst...

--riverman


As I said, it's a desperation measure. If you can keep your head above
water long enough for someone to rescue you, you're better off not
taking the chance.

However... If you look at the typical water flow of a low-head, the
water first goes down and along the bed, away from the lip of the dam
before it doubles back. It's the only path where the water takes you to
safety rather than holding you against the top flow. I've never use it,
and I certainly don't intend to experiment, but the logic is reasonable.

Low-head dam drowning on Yakima River, WA State
 

Per Wilko:
It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if needed.

This thread is making me re-think my practice of tying that waist band on my
PFD...
--
PeteCresswell

Low-head dam drowning on Yakima River, WA State
 

"Bob P" wrote in message
.net...
riverman wrote:
"Wilko" wrote in message
...
Bob P wrote:
In desperate circumstances, you're better off taking off the PFD and
diving down to follow the bottom current out of the backwash. Few
people who get in (low-head-dam) trouble have the knowledge or
composure to make that radical move, however.
I've given that some thought. Over the years, this option seems to have
surfaced on RBP a couple of times. My main concern would be what happens
after you get out of the hydrolic, and what would happen if taking off
your PFD wouldn't get you out. I'm fairly ambiguous about whether or not
that would be a smart thing to do. It's the main reason why I have a PFD
with a front zipper though... so that I can quickly take it off if
needed.

This boondoggle arises all the time.

As far as my experience goes, the old "take off your PFD and flush out
the bottom of the hole" strategy is an urban legend. Everyone knows the
rule, but afaik, no one knows anyone who has actually had to do it. Its
in the same legendary category as putting maggots in an open wound to
stymie gangrene from forming, ...

Actually, maggots are now occasionally used in hospitals to eat dead
flesh.


Yes, I know. But I was referring more to the 'Jungle Jim survival' scenario
that makes the Reader's Digest Drama in Real Life pages.



I think if you were actually trapped in a hole with sharp enough edges to
keep you in, you would be underwater and tossed around so much that you
would have no idea which way 'down' was, let alone how to crawl along the
bottom. Also, once you shed your pfd, the force of the water would almost
certainly prevent you from using the rocks along the bottom anyway, as
you'd be plastered down there at best, or slammed among them at worst...

--riverman

As I said, it's a desperation measure. If you can keep your head above
water long enough for someone to rescue you, you're better off not taking
the chance.

However... If you look at the typical water flow of a low-head, the water
first goes down and along the bed, away from the lip of the dam before it
doubles back.

Well, that's certainly the theory. In reality, the 'break line' where the
current splits surges around quite a bit (in all but the most surgically
designed dams), there are bursts and boils that erupt in various places, and
the bottom of the river is usually anything but regular. I think the
hydrodynamic model that we all look at is most accurate in man-made
spillways, with precise and consistent angles, concrete bottoms and very
clean riverbeds. And only somene with a death wish would be running
something like that: those are true killing machines. In the natural world,
there are always lots of little variations and 'irregularities' that affect
the model.

It's the only path where the water takes you to safety rather than holding
you against the top flow. I've never use it, and I certainly don't intend
to experiment, but the logic is reasonable.

Sure, if you assume that all the natural variations don't exist. All logic
is reasonable is you start with 'lets ignore any diversity to the model'.
Its like that old joke about the mathematician, the physicist and the
engineer betting on a horserace, and the mathematician says 'assume a
spherical horse'. :-)

--riverman

Low-head dam drowning on Yakima River, WA State
 

riverman wrote:
"Bob P"

It's the only path where the water takes you to safety rather than holding
you against the top flow. I've never use it, and I certainly don't intend
to experiment, but the logic is reasonable.

Sure, if you assume that all the natural variations don't exist. All logic
is reasonable is you start with 'lets ignore any diversity to the model'.
Its like that old joke about the mathematician, the physicist and the
engineer betting on a horserace, and the mathematician says 'assume a
spherical horse'. :-)

--riverman

So you wouldn't try the maneuver even if you knew you were going to
drown if you did nothing?

Here's a little story. It happened to me about 20 years ago.

We were paddling the Thurmond-to-Fayette section of the New River (WV)
at fairly low water.

About 2/3 of the way down there's an huge rock on river right (unknown
to me as The Undercut Rock). I had run the rapid a couple of times
before at high water and pillowed off the rock quite nicely. This time,
however, I came right up to the rock, broached and flipped upstream.
The boat was sucked down, down, down and finally lodged quite nicely
upside down with me in it. I popped my skirt, undid my thigh straps,
and tried to push myself out of the boat, but the water pressure kept me
pinned. Tried again, and again.

Hey! I'm going to die here! Time for a Desperation Move!

I reached above my head (actually down) and, (Holy Crap!) there was the
cockpit rim of another pinned boat below me. Somehow, I was then able
to pull myself out using the cockpit rim. I guess that the extra reach
was enough to get me all the way out of the boat.

I pushed off and was able to get into the current enough to get around
the rock. Come on Charlie Walbridge (pfd)!!! I reached the surface
just before I was about to take a nasty breath of water.

My boat came out 2 days later, when the water dropped even more.

So sometimes you do things, even if they have a low probability of success.

Low-head dam drowning on Yakima River, WA State
 

"Bob P" wrote in message
. com...
riverman wrote:
"Bob P"
It's the only path where the water takes you to safety rather than
holding you against the top flow. I've never use it, and I certainly
don't intend to experiment, but the logic is reasonable.

Sure, if you assume that all the natural variations don't exist. All
logic is reasonable is you start with 'lets ignore any diversity to the
model'. Its like that old joke about the mathematician, the physicist and
the engineer betting on a horserace, and the mathematician says 'assume a
spherical horse'. :-)

--riverman
So you wouldn't try the maneuver even if you knew you were going to drown
if you did nothing?

Here's a little story. It happened to me about 20 years ago.

We were paddling the Thurmond-to-Fayette section of the New River (WV) at
fairly low water.

About 2/3 of the way down there's an huge rock on river right (unknown to
me as The Undercut Rock). I had run the rapid a couple of times before at
high water and pillowed off the rock quite nicely. This time, however, I
came right up to the rock, broached and flipped upstream. The boat was
sucked down, down, down and finally lodged quite nicely upside down with
me in it. I popped my skirt, undid my thigh straps, and tried to push
myself out of the boat, but the water pressure kept me pinned. Tried
again, and again.

Hey! I'm going to die here! Time for a Desperation Move!

I reached above my head (actually down) and, (Holy Crap!) there was the
cockpit rim of another pinned boat below me. Somehow, I was then able to
pull myself out using the cockpit rim. I guess that the extra reach was
enough to get me all the way out of the boat.

I pushed off and was able to get into the current enough to get around the
rock. Come on Charlie Walbridge (pfd)!!! I reached the surface just
before I was about to take a nasty breath of water.

My boat came out 2 days later, when the water dropped even more.

So sometimes you do things, even if they have a low probability of
success.

Great tale! Its sort of spooky, too!

Sure, we all try Desperation Moves when in desperate situations, and any
paddler with tons of experience will have a tale to tell. But promoting the
'shed the PFD' anecdote from 'Desperation Move' to 'River Strategy' is
inappropriate, imnsho. Desperation Moves are born of specific situations
mixed with a paddler's experience and assessment of what to do right there,
right now. They aren't universally applicable, and its useless to try to
learn them all. There are a bazillion 'desperation moves'....we all have our
tales. But 'self-rescue strategies' are, or should be, tried and tested
strategies that all river runners are familar with and that have a high
record of success; not in theory, but in commonly encountered situations.
This one doesn't seem to fit the mold of such things as, say, breathing in
the air pocket in front of your face when trapped in a vertical pin, or some
of the various rope tricks for unpinning boats, or dragging a line across
the river to free a foot entrapment. Those were all originally 'desperation
moves' that have become 'rescue strategies' that everyone has heard about.

--riverman

Low-head dam drowning on Yakima River, WA State
 

Thanks to Paul & John for answering my question ... and everyone else
for sharing their info & stories. Y'all taught me something today!