PSDarchives.contingencybottles

3-3-03

Craig writes: We were taught the "pass the pony" technique in the LGS
RDSR/R/R course, and are not using it. When the diver signals that they are
in trouble or low/out of air, the backup automatically goes down with the
contingency bottle. We do not just send in the backup to check it out and
pass off the pony ... it seemed like a redundant step. It also allows the
backup to retain his/her pony in case some other problem crops up."

Tom Peddle answered very well and succinctly. Not one of my skills. I just
read his email after writing these two part. I'll send these two postings
anyway because they do provide some additional specifics. Well done Tom.
Thank you.

Yes, definitely do not take things as Gospel. You are right Craig, we always
preach, "question everything that anyone teaches you." What I see we should
add is when a team is taught something first question it. Then, if you think
you have a better idea, before instituting the "better idea" a team might
want to ask the instructors why they do not use that idea. There could be
two reasons - one, that the instructors never thought of it. And if that is
the case, then the instructors should go out and test it on a few hundred or
even thousand dives, and should look at past history to see if that idea is
better. If it is better, then the training agency should change their SOP
and teach the new idea.

Members of dive teams come up with good ideas all the time. And I know that
we learn and make improvements from these ideas. But if a team decides to
change something that they were taught - it might be worthwhile to ask the
instructors what they think of the new idea because there is a very good
chance that the instructors have already tried and tested that idea and
found it not to be the best way. If your instructors have 15, 20, 30 years
of experience with tens of thousands of PSD dives, take advantage of that
knowledge. That was one of the reasons we started this discussion group
years ago - to let divers access each other's experience and to ask
experience from those on the group with exceptional experience like Butch
and Blades.

Before procedures are changed they should be thoroughly researched and
tested- I believe Blades
would agree. I believe this is an extremely important
topic because there were many procedures that were taught 20 years ago -
just in basic diving skills that were changed without lots of good research.
Sometimes the changes were positive, sometimes they were negative. A sport
diving
example would be putting the octopus on the right instead of on the left
where it originally started, and where it should be, for a variety if
reasons (that we can discuss if anyone is interested).

This example of contingency plans is a great example, and thank you Craig
for
bringing it up. We are asked this question not infrequently "why don't you
just have the backup diver go down with the contingency bottle every time
the backup is called for?" I asked Butch that question about 15 years ago.
Here was his answer that to me makes lots of sense, and is why we don't
teach that procedure today.

The first issues are that 99.999999% of the time all the primary diver is
asking for help for is a minor entanglement problem, or in rare cases a leg
cramp. In the 16 years that I have been doing this full time, running many
thousands of PSD dives, I have never had a diver every need air from a
backup diver. Butch has more than twice that experience with PSD and can say
the same thing. Then, we ask the teams we have trained and for many tens of
thousands of dives they have conducted - we have yet to hear of a primary
diver who needed air from a back up diver.

Therefore, regarding what is being suggested by this team: "When the diver
signals that they are in trouble or low/out of air, the backup automatically
goes down with the contingency bottle." - Where are the cases histories to
support that this needed or even a good idea.

Doing this, sending in a contingency tank every time a diver asks for
assistance, would be equivalent to sending in a SWAT team any time an
officer asked for the assistance of an officer. Not only is there no reason
for it, but it can actually do more harm than good. That is the key here -
Doing this can actually turn a very small problem and make it into a bigger
one. It is an additional task that is not necessary for the backup diver to
do. This is not an issue of "better safe than sorry" because bringing what
is not needed is not always being safer. And if more air is needed, then
there is fully tested plan in place to follow to safely and efficiently get
it to the primary diver.

Butch is the first one that I know of who instituted a mandatory, fully
ready contingency 80 cuft bottle on site with a harness system to make it easy to
bring down and use. So we are not saying that a contingency bottle is not a
good idea.

But, the contingency cylinder concept was designed to be brought down only
when it is needed. Even with a good harness system it is a little cumbersome
to bring down and just basically gets in the way when attempting to do other
things. Imagine a back up diver who now has to manage an 80 cuft
contingency bottle and control buoyancy and find out what is wrong with the
primary diver. When the entanglement or leg cramp problem is discovered,
what is the backup diver supposed to do with the contingency bottle? Leave
it attached to the tether line? Try and hold on to it? It can actually
become more than an annoyance as the backup diver works to free a diver from
fish hooks and lines, or work a leg cramp out. The contingency bottle is
safe and effective when it is needed. It may not be so when is brought down
and not needed.

Let us start by looking at why the contingency bottle is so rarely needed by
dive teams who follow our procedures that its use is literally unheard of.
Before we do that though, please understand that there have been divers who
have died due to lack of air - but not anyone that we trained that follows
our procedures. If you follow these procedures, it is nearly impossible to
ever use up your air. If you do not follow the following procedures, then
yes, you may want to bring a contingency tank down every time because the
diver might need air:

Here's how to prevent a diver ever needing a contingency bottle within a
miniscule percentile:

1. Max dive times are 20-25 minutes with max depths of 60 feet - for divers
with less than 50 psi/min SAC rates. Most of our students range from 15 to
35 psi/min SAC rates.

2. Divers are back on deck with a minimum of 1000 psi and a full pony
bottle.

3. Backup tenders monitor and record the primary diver's breathing rate for
a full minute every 5 minutes. Any diver who exceeds their normal breathing
rate significantly, or who exceeds 20 breaths per minute is stopped with
several procedures to follow to correct the situation to abort the dive.

4. Backup tenders (who are also the information recorders) can say within
200 psi how much air a diver has at any point during the dive by looking at
the diver's BPM (breath per minted) rate and applying knowledge of the
diver's normal SAC rate. For example, a diver normally breathes 9-10 BPM and
normally has a SAC rate of 20 psi/min. The diver is now at 30 feet so the
diver's air consumption now is about 40 psi/min. As long as the diver is
breathing his normal 9-10 BPM, the diver is using his normal 40 psi/min, so
if the diver has been down ten minutes, then about 400 psi has been used. If
the divers started with 2900 psi, then the diver now has about 2500 psi. So
in blackwater we know how much air the diver has.

So, with the max dive times and depths, and the constant monitoring of a
diver's BPM, along with a good idea of how much air the diver has at any
point in time you can basically prevent out-of-air emergencies. Now, yes, a
catastrophic equipment failure could occur, such as a low pressure hose
blows, or a pp AGA free flow causes a first stage free flow. No problem.
That is why we have pony bottles. So when the problem occurs, the divers
start for the surface or ice hole. The chances are that the diver will have
enough air left in the cylinder if the above procedures will followed, to
get back to the surface. But Murphy's Law, it was the end of the dive and
the main 80 cuft cylinder runs dry. No big deal, you have a pony bottle to
finish the ascent with plenty of time and air.

The only time you would need a contingency bottle is if the diver
experienced both an out-of-air emergency AND was entrapped or entangled on
the bottom so that the diver could not get back to the surface in time - or
was not following safe overhead diving procedures and could not find the
surface. If it was the latter case, then that means the diver was not
tethered to a tender, so what realistic good is a contingency bottle since
there is no line for the back up diver to find the primary diver before the
diver stops breathing?

Should there be a contingency bottle - yes, of course - but understand that
if proper procedures are used the chance of needing that bottle are slim to
none. So putting it in the system for every time a backup diver responds is
not backed by real life experience.

Now let us look at what happens when a diver asks for assistance.

We have three different help signals, similar to what military and
commercial divers use. "2+2+2" means I'm having a problem, but I am okay,
and I'm going to deal with it myself. Just alert the back up diver. "3+3+3"
I'm having a problem, I am fine, but I do need the backup diver. "4+4+4....
Continuous till help arrives" means I need immediate assistance now, I am
not okay.

We have yet to ever receive a 4+4+4... - but if you want to have a policy
of bringing down a contingency bottle without it being asked for, then it
would only make sense to bring it down if that signal was received.

Okay, so primary dive gives a 3+3+3. When a diver calls for help, we have a
very good idea of what the diver's air situation is, and the backup diver
immediately tells the site commander, "John just asked for assistance and he
has approximately 2200 psi left. His breathing rate just increased by 4 BPM
above his normal, so I believe in two to three minutes he will be down to
possibly 1900 psi." The back up diver should be able to get down and learn
what the problem is (through a series of practiced hand to hand signals) in
less than two minutes. So why bring a contingency bottle - it takes a little
more time and in the least can be an unnecessary annoyance.

To summarize, we do not suggest bringing a bottle down that is not needed.
It can make it more difficult for the backup diver to manage the true
problem. That procedure increases the risk with basically no benefit. No
benefit because the chances of it being needed without the tenders realizing
that should be basically nil.

The last point is that there is more than one reason why we use quick
release pony bottles. It is not just for the back up diver to pass off to
the primary diver. The quick release pony bottle allows a diver who is
entrapped/entangled in their BCD assembly to ditch the assembly, remove the
pony, and make a controlled ascent to the surface. A diver in NJ entangled
in a gill net was saved by this procedure that he learned two weeks prior to
the incident in a Rapid Deployment Search & Rescue/Recovery class.

Definitely keep on questioning everything you are taught.

Definitely keep on striving to find better ways to do things - everything
can be improved.

Definitely, before making changes, find out if anyone has tried that "new"
idea before and see what the results were.

Always looking to learn and improve, so keep those ideas coming.

Andrea Zaferes
Lifeguard Systems & RIPTIDE

3-3-03

how can you tell if the diver is having a problem and the tender line is partly around a tree stump or another object preventing pull communication?...Chuck

3-4-03

I have a thought on this paragraph:

But, the contingency cylinder concept was designed to be brought down
only
when it is needed. Even with a good harness system it is a little
cumbersome
to bring down and just basically gets in the way when attempting to do
other
things. Imagine a back up diver who now has to manage an 80 cuft
contingency bottle and control buoyancy and find out what is wrong with
the
primary diver. When the entanglement or leg cramp problem is
discovered,
what is the backup diver supposed to do with the contingency bottle?
Leave
it attached to the tether line? Try and hold on to it? It can actually
become more than an annoyance as the backup diver works to free a diver
from
fish hooks and lines, or work a leg cramp out

As stated in another post. There is a signal for "I am having a problem and could use some assistance." and "HELP!". So a contingency bottle would not go down in every instance, perhaps only in the "HELP!" mode. While line signals can be vague, they should just be a back-up to the comm's. With the comm's one can better send the appropriate help! But if the comm fails you have a back up.

In cave diving there is a primary light and a (2) back up lights. When the primary fails one switches to a back up. At this time the dive is terminated until all equipment is again fully functional. The back up just gives a means to safely terminate the dive. Perhaps comms could be used the same?

Could there be a situation that a smaller bottle would work? Perhaps a 63cf, or a 50cf bottle? One switch here is you can not go by psi per minute. It has to become the standard to go by Cubic feet per minute for the divers breathing rate. You figure this out by converting psi/min to cf. /min.

Now to transport that contingency (it works for larger and smaller) tank. I am not familiar with the harness system, but we started using a stage bottle set-up. You might be familiar with this from cave or tek diving. A contingency bottle should not be getting in the way of ones procedures or have any effect on their buoyancy or have the divers stressed as to were it can be tied to free ones hands. The stage set up places the bottle securely to the diver and it is in front. Since entanglement is always a concern, the diver has the most mobility in front to deal with that problem or avoiding that problem all together. On the stage set up it is suggested to use a "bolt type" snap as opposed to the "suicide type". I apologize for not knowing the proper names for these snaps, but this can also help avoid an entanglement.

Sincerely,
Don Alan Ruschak
Mon Valley Divers, PA.

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