Inflator-integrated octopus

Her is an unpublished article I wrote a few years ago. Near the end is
a section on "Combined" or "Collocated", which addresses this question.

Note that this article has not undergone peer review -- although it may
do so now! Also note taht I have not re-read or updated this
recently. If I did so, some thing might be added, deleted or changed.

Enjoy!


BACKUP REGULATORS
The "Alternate Air Source"

28 August 2000
Charles W Hammond

Copyright 2000 Charles W Hammond, Boca Raton, Florida, USA

All rights reserved. May be copied for personal use or for non-
commercial distribution provided that this copyright notice
remains with all copies and that no charge is made for copying or
distribution.
-------
DISCLAIMER: SCUBA diving can be dangerous if you are not properly
trained. DO NOT purchase or use ANY SCUBA equipment unless you are
a properly certified diver or diving student. DO NOT dive beyond
the limits of your training and experience. The information
presented here reflects my opinion only; it is not sanctioned by
any certifying agency. Other opinions will differ.
-------


Not too many years ago, divers dove with a single second stage. In
an out of air emergency, a diver could share his remaining air
with a diver who was out of air only by passing the second stage
back and forth between the divers. This method of sharing air,
called "Buddy Breathing", is generally thought to be dangerous. It
is widely believed that Buddy Breathing often leads to a double
drowning rather than to a successful rescue. (See note 1.)

Today, virtually all SCUBA divers carry two second stages: They
breath from their primary second stage; the other second stage is
a backup or "alternate" which is used when it becomes necessary to
share air with another diver. There are several ways to configure
primary and backup second stages. The method most commonly taught
in Basic Open Water classes is not the only way and may not be the
best way.

SCUBA divers should understand these different configurations for
two reasons: Because emergency procedure will differ depending on
the configuration, all divers may need to recognize and react
properly to the different configurations they may experience in an
actual emergency. Divers also need to be able to make informed
decisions about how they will configure the gear that they
purchase and use.

Regulator configuration will depend on which of two options is
chosen for the first stage, and which of three options for the
second stage. There are four viable combinations that are
discussed here. (See note 2.)

The PRIMARY second stage is most commonly connected to the first
stage with at 28-36 inch hose that comes over the right shoulder.
I will call this the "Short Hose" primary.

When using the Short Hose primary, the most common configuration
for the backup second state is a hose 36-40 inches long routed
under the diver's right arm. The backup second stage should be
secured somewhere more-or-less in the middle of the diver's chest,
where it is easily found and readily available. This is the
"octopus" method most commonly taught in Basic Open Water courses.
Unfortunately, the "Octopus" is often just left to float free and
trail behind the diver instead of being secured. (See note 3.)

When using this "Octopus" configuration, an out-of-air diver would
take the donor's backup second stage while the donor continues to
breath from the primary. At least that is how it is usually
taught. Actually, either diver can use either regulator, although
the slightly longer hose on the Octopus makes it preferable for
the out of air diver, rather than the donor, to breath the
octopus.

Another configuration with the Short Hose primary is for the
BACKUP second stage to be located on the same hose with the power
inflator. (See side bar.) In this configuration, the out-of-air
diver is given the donor's primary second stage and the donor
switches to the backup.

Technical divers, cave and wreck divers in particular, sometimes
find themselves in situations in which it is not possible for two
divers to swim side by side. This causes problems if divers are
sharing air and need to swim single file to exit from the cave or
wreck. The solution to this is to place the primary second stage
on a 7 foot hose. (See note 4.) This hose is routed under the
diver's right arm, across the front of the body, back over the
left shoulder, behind the head and finally front over the right
shoulder. I will call this the "Long Hose" primary. The long hose
is kept tight to the body either by catching the extra length
under a pocket or light canister on the right hip, or by tucking
it into a cumberbund or waist belt.

When using the Long Hose primary, the backup second stage is most
commonly routed exactly like the short hose primary, and held in
place below the diver's chin by a loop of surgical tubing or bungy
cord around the divers neck. The Long Hose primary can also be
used with a BACKUP second stage located on the same hose with the
power inflator. (Some of the limitations of this -- see side bar
-- may not be acceptable in cave or technical applications.)

Regardless of which backup second stage is used with the long
hose, it is always the primary second stage that is donated to the
out-of-air diver. When the divers cannot swim side by side, the
out-of-air diver always goes first. If the donating diver were to
go first, he could pull the second stage from the out-of-air
diver's mouth and possibly swim away without realizing this. It is
very unlikely that the out-of-air diver will swim away from his
air source!

For the record, I currently have my primary first stage on a seven
foot hose, and use a US Divers/Aqualung AirMic for my backup
second stage. However, for the Introduction to Cavern Diving
course that I took last year, I converted to an alternate second
stage with a loop of surgical tubing around my neck. I am
seriously considering making this conversion permanent; the
improved functionality may well be worth the slight extra
drag/bother of one additional hose.

[Added 2003-MAR-13]
Since writing this article, I have converted to using an alternate
second stage with a loop of surgical tubing around my neck. I
believe that this, along with the Long Hose Primary, provides a
valuable safety increment in open water as well as cave diving.


-------------------(side bar)-------------------

"Combined" or "Collocated"

When the BACKUP second stage is Located on the same hose with
power inflator, one of two approaches can be taken. The power
inflator and backup second stage can be combined into a single
unit. This is the approach taken by the ScubaPro Air2 system. The
other approach is to retain separate power inflator and second
stage units, but to supply them from the same hose. US Divers/
Aqualung's "AirMic" system does this with a special fitting. By
using a "Y" adapter between the power inflator hose and the power
inflator, nearly any regulator can be collocated with the power
inflator.

There are reports that combined units do not function as well in
either the power inflator or seconds stage role as do separate
units. There are stories heard that early combined units had
quality problems, which may have since been corrected. Since the
author believes that the backup second stage should be at least as
good as the primary, the "collocated" style may be preferred.

The disadvantages of this configuration include the possibly lower
quality of a combined regulator/inflator unit; the limits to
turning your head when when breathing this second stage; and the
difficulty of managing buoyancy while breathing this second stage.
Managing buoyancy may be more difficult with a combined unit than
with a collocated unit. However, either one requires practice
under controlled conditions to ensure it can be properly used in
an actual emergency.

The advantages of this configuration are obvious: One less hose is
used, which reduces drag and neatens up the diver's kit. Also,
because you use the power inflator during every dive, you are
constantly practicing locating it. Finally if a redundant air
supply -- a "pony" bottle -- is used, this configuration makes it
possible to manage three second stages reasonably well. The
backup second stage is on the low pressure inflator hose and the
redundant second stage from the pony bottle can be worn in the
"octopus" or "necklace" configuration.


--------------------(notes)---------------------

Note 1: Although the danger of Buddy Breathing is often asserted,
the author is not familiar with any statistics that backup this
claim. It does seem clear that under the stress of an emergency,
and in possibly difficult conditions, successful Buddy Breathing
could be very difficult.

Note 2: Many other configurations are possible for both primary
and alternate second stages. For practical purpose, this
discussion is limited to the more common choices.

Note 3: An alternate second stage the is left to float free is a
bad idea. Not only can it be difficult to find in an emergency,
but it can be damaged by dragging in sand or silt, or banging
against rocks, coral, etc.

Note 4: Lengths of 5-9 feet are in use. Lengths under 7 feet are
often found to be too short for some emergency conditions, while
lengths over 7 feet are seldom required.


--
Charlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA
(hammond@not@peek.ssr.hp.com -- remove "@not" when replying)
All opinions expressed are my own and not necessarily my employer's.

Her is an unpublished article I wrote a few years ago. Near the end is
a section on "Combined" or "Collocated", which addresses this question.

Note that this article has not undergone peer review -- although it may
do so now! Also note taht I have not re-read or updated this
recently. If I did so, some thing might be added, deleted or changed.

Enjoy!


BACKUP REGULATORS
The "Alternate Air Source"

28 August 2000
Charles W Hammond

Copyright 2000 Charles W Hammond, Boca Raton, Florida, USA

All rights reserved. May be copied for personal use or for non-
commercial distribution provided that this copyright notice
remains with all copies and that no charge is made for copying or
distribution.
-------
DISCLAIMER: SCUBA diving can be dangerous if you are not properly
trained. DO NOT purchase or use ANY SCUBA equipment unless you are
a properly certified diver or diving student. DO NOT dive beyond
the limits of your training and experience. The information
presented here reflects my opinion only; it is not sanctioned by
any certifying agency. Other opinions will differ.
-------


Not too many years ago, divers dove with a single second stage. In
an out of air emergency, a diver could share his remaining air
with a diver who was out of air only by passing the second stage
back and forth between the divers. This method of sharing air,
called "Buddy Breathing", is generally thought to be dangerous. It
is widely believed that Buddy Breathing often leads to a double
drowning rather than to a successful rescue. (See note 1.)

Today, virtually all SCUBA divers carry two second stages: They
breath from their primary second stage; the other second stage is
a backup or "alternate" which is used when it becomes necessary to
share air with another diver. There are several ways to configure
primary and backup second stages. The method most commonly taught
in Basic Open Water classes is not the only way and may not be the
best way.

SCUBA divers should understand these different configurations for
two reasons: Because emergency procedure will differ depending on
the configuration, all divers may need to recognize and react
properly to the different configurations they may experience in an
actual emergency. Divers also need to be able to make informed
decisions about how they will configure the gear that they
purchase and use.

Regulator configuration will depend on which of two options is
chosen for the first stage, and which of three options for the
second stage. There are four viable combinations that are
discussed here. (See note 2.)

The PRIMARY second stage is most commonly connected to the first
stage with at 28-36 inch hose that comes over the right shoulder.
I will call this the "Short Hose" primary.

When using the Short Hose primary, the most common configuration
for the backup second state is a hose 36-40 inches long routed
under the diver's right arm. The backup second stage should be
secured somewhere more-or-less in the middle of the diver's chest,
where it is easily found and readily available. This is the
"octopus" method most commonly taught in Basic Open Water courses.
Unfortunately, the "Octopus" is often just left to float free and
trail behind the diver instead of being secured. (See note 3.)

When using this "Octopus" configuration, an out-of-air diver would
take the donor's backup second stage while the donor continues to
breath from the primary. At least that is how it is usually
taught. Actually, either diver can use either regulator, although
the slightly longer hose on the Octopus makes it preferable for
the out of air diver, rather than the donor, to breath the
octopus.

Another configuration with the Short Hose primary is for the
BACKUP second stage to be located on the same hose with the power
inflator. (See side bar.) In this configuration, the out-of-air
diver is given the donor's primary second stage and the donor
switches to the backup.

Technical divers, cave and wreck divers in particular, sometimes
find themselves in situations in which it is not possible for two
divers to swim side by side. This causes problems if divers are
sharing air and need to swim single file to exit from the cave or
wreck. The solution to this is to place the primary second stage
on a 7 foot hose. (See note 4.) This hose is routed under the
diver's right arm, across the front of the body, back over the
left shoulder, behind the head and finally front over the right
shoulder. I will call this the "Long Hose" primary. The long hose
is kept tight to the body either by catching the extra length
under a pocket or light canister on the right hip, or by tucking
it into a cumberbund or waist belt.

When using the Long Hose primary, the backup second stage is most
commonly routed exactly like the short hose primary, and held in
place below the diver's chin by a loop of surgical tubing or bungy
cord around the divers neck. The Long Hose primary can also be
used with a BACKUP second stage located on the same hose with the
power inflator. (Some of the limitations of this -- see side bar
-- may not be acceptable in cave or technical applications.)

Regardless of which backup second stage is used with the long
hose, it is always the primary second stage that is donated to the
out-of-air diver. When the divers cannot swim side by side, the
out-of-air diver always goes first. If the donating diver were to
go first, he could pull the second stage from the out-of-air
diver's mouth and possibly swim away without realizing this. It is
very unlikely that the out-of-air diver will swim away from his
air source!

For the record, I currently have my primary first stage on a seven
foot hose, and use a US Divers/Aqualung AirMic for my backup
second stage. However, for the Introduction to Cavern Diving
course that I took last year, I converted to an alternate second
stage with a loop of surgical tubing around my neck. I am
seriously considering making this conversion permanent; the
improved functionality may well be worth the slight extra
drag/bother of one additional hose.

[Added 2003-MAR-13]
Since writing this article, I have converted to using an alternate
second stage with a loop of surgical tubing around my neck. I
believe that this, along with the Long Hose Primary, provides a
valuable safety increment in open water as well as cave diving.


-------------------(side bar)-------------------

"Combined" or "Collocated"

When the BACKUP second stage is Located on the same hose with
power inflator, one of two approaches can be taken. The power
inflator and backup second stage can be combined into a single
unit. This is the approach taken by the ScubaPro Air2 system. The
other approach is to retain separate power inflator and second
stage units, but to supply them from the same hose. US Divers/
Aqualung's "AirMic" system does this with a special fitting. By
using a "Y" adapter between the power inflator hose and the power
inflator, nearly any regulator can be collocated with the power
inflator.

There are reports that combined units do not function as well in
either the power inflator or seconds stage role as do separate
units. There are stories heard that early combined units had
quality problems, which may have since been corrected. Since the
author believes that the backup second stage should be at least as
good as the primary, the "collocated" style may be preferred.

The disadvantages of this configuration include the possibly lower
quality of a combined regulator/inflator unit; the limits to
turning your head when when breathing this second stage; and the
difficulty of managing buoyancy while breathing this second stage.
Managing buoyancy may be more difficult with a combined unit than
with a collocated unit. However, either one requires practice
under controlled conditions to ensure it can be properly used in
an actual emergency.

The advantages of this configuration are obvious: One less hose is
used, which reduces drag and neatens up the diver's kit. Also,
because you use the power inflator during every dive, you are
constantly practicing locating it. Finally if a redundant air
supply -- a "pony" bottle -- is used, this configuration makes it
possible to manage three second stages reasonably well. The
backup second stage is on the low pressure inflator hose and the
redundant second stage from the pony bottle can be worn in the
"octopus" or "necklace" configuration.


--------------------(notes)---------------------

Note 1: Although the danger of Buddy Breathing is often asserted,
the author is not familiar with any statistics that backup this
claim. It does seem clear that under the stress of an emergency,
and in possibly difficult conditions, successful Buddy Breathing
could be very difficult.

Note 2: Many other configurations are possible for both primary
and alternate second stages. For practical purpose, this
discussion is limited to the more common choices.

Note 3: An alternate second stage the is left to float free is a
bad idea. Not only can it be difficult to find in an emergency,
but it can be damaged by dragging in sand or silt, or banging
against rocks, coral, etc.

Note 4: Lengths of 5-9 feet are in use. Lengths under 7 feet are
often found to be too short for some emergency conditions, while
lengths over 7 feet are seldom required.


--
Charlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA
(hammond@not@peek.ssr.hp.com -- remove "@not" when replying)
All opinions expressed are my own and not necessarily my employer's.

"DS" <davidscott@shaw.ca> wrote in message
news:JARuf.18689$tl.16356@pd7tw3no...
> How easy could it be to control your buoyancy during an emergency ascent
> with either your combo in your mouth or your buddy's mouth?

It isn't easy even under the best of circumstances. Forget the fumbling
with the single hose for venting your BC and focus on the other BC and a
couple of drysuits.

"DS" <davidscott@shaw.ca> wrote in message
news:JARuf.18689$tl.16356@pd7tw3no...
> How easy could it be to control your buoyancy during an emergency ascent
> with either your combo in your mouth or your buddy's mouth?

It isn't easy even under the best of circumstances. Forget the fumbling
with the single hose for venting your BC and focus on the other BC and a
couple of drysuits.

In article <1136389633.240914.199970@g14g2000cwa.googlegroups .com>,
Mick <micknewton@direcway.com> wrote:

€ Alan Street wrote:
€ > Having said that, my daughter has an A.I.R. 2 and loves it. She has a
€ > BC with multiple dump valves, and has made entire dives breathing off
€ > the backup without any problems (although she's been known to put up
€ > with a less-than-ideal situation just to make a point .
€
€ Sounds like my daughter. :)
€
€
€ > Well, not the back-up's hose
€ >
€ > Here's an example (note that this is not necessarily an endorsement of
€ > Halcyon, just DIR-L).
€
€ So, the hose comes up under your right arm, across your chest, then
€ around behind your neck and over your right sholder, correct? Is this
€ what you meant by necklaced?
€
€ It looks like a practical way of dealing with a really long hose.
€

The primary's long hose is routed under the right arm and around the
neck. The backup is "necklaced" on a short hose by zip-tying a piece of
rubber tubing or shock cord to the regulator mouthpiece. The tubing is
worn around the neck, holding the back-up under your chin.

http://www.wkpp.org/images/pina_equi..._attach_r.jpeg

http://www.wkpp.org/images/pina_equip/regs_setup.jpg


For open water, a shorter primary hose is often used (5' instead of
7'), and the routing is just once around the neck.

In article <1136389633.240914.199970@g14g2000cwa.googlegroups .com>,
Mick <micknewton@direcway.com> wrote:

€ Alan Street wrote:
€ > Having said that, my daughter has an A.I.R. 2 and loves it. She has a
€ > BC with multiple dump valves, and has made entire dives breathing off
€ > the backup without any problems (although she's been known to put up
€ > with a less-than-ideal situation just to make a point .
€
€ Sounds like my daughter. :)
€
€
€ > Well, not the back-up's hose
€ >
€ > Here's an example (note that this is not necessarily an endorsement of
€ > Halcyon, just DIR-L).
€
€ So, the hose comes up under your right arm, across your chest, then
€ around behind your neck and over your right sholder, correct? Is this
€ what you meant by necklaced?
€
€ It looks like a practical way of dealing with a really long hose.
€

The primary's long hose is routed under the right arm and around the
neck. The backup is "necklaced" on a short hose by zip-tying a piece of
rubber tubing or shock cord to the regulator mouthpiece. The tubing is
worn around the neck, holding the back-up under your chin.

http://www.wkpp.org/images/pina_equi..._attach_r.jpeg

http://www.wkpp.org/images/pina_equip/regs_setup.jpg


For open water, a shorter primary hose is often used (5' instead of
7'), and the routing is just once around the neck.

"DS" wrote

> How easy could it be to control your buoyancy during an emergency ascent
> with either your combo in your mouth or your buddy's mouth? You're holding
> your buddy's BCD, sharing air and trying to deflate your BCD with a combo
> that is in someone's mouth.

You have a shoulder dump, right? Pull the hose, dump the BCD. It's not a
problem.

> This all seems too dangerous for my liking. I'll stick to the separate
> octopus. Personal preference? Certainly, but it just seems easier and
> safer. You want as few complications as possible in an emergency
> situation.

Only because you haven't spent the time to work out how everything fits
together.
You may prefer what you have. In fact, I prefer something other than a
combination
unit, but I used one quite successfully for a lot of years. Like I said,
it's a matter
of personal preference. I don't use one. My wife still does.

> Plus, I've never seen a brightly coloured combo inflator hose before. All
> the ones I've seen are black. In low vis situations, it might be hard to
> spot.

The combiantion units are deliberately drab. They are not suitable for use
by the
donee. The primary is handed off/taken and the alternate is used by the
donor.
You don't have to spot it. You know right where it will be every time . . .
just
like my necklaced alternate.

Lee

"DS" wrote

> How easy could it be to control your buoyancy during an emergency ascent
> with either your combo in your mouth or your buddy's mouth? You're holding
> your buddy's BCD, sharing air and trying to deflate your BCD with a combo
> that is in someone's mouth.

You have a shoulder dump, right? Pull the hose, dump the BCD. It's not a
problem.

> This all seems too dangerous for my liking. I'll stick to the separate
> octopus. Personal preference? Certainly, but it just seems easier and
> safer. You want as few complications as possible in an emergency
> situation.

Only because you haven't spent the time to work out how everything fits
together.
You may prefer what you have. In fact, I prefer something other than a
combination
unit, but I used one quite successfully for a lot of years. Like I said,
it's a matter
of personal preference. I don't use one. My wife still does.

> Plus, I've never seen a brightly coloured combo inflator hose before. All
> the ones I've seen are black. In low vis situations, it might be hard to
> spot.

The combiantion units are deliberately drab. They are not suitable for use
by the
donee. The primary is handed off/taken and the alternate is used by the
donor.
You don't have to spot it. You know right where it will be every time . . .
just
like my necklaced alternate.

Lee

"Mick" >> Here's an example (note that this is not necessarily an
endorsement of
>> Halcyon, just DIR-L).

> So, the hose comes up under your right arm, across your chest, then
> around behind your neck and over your right sholder, correct? Is this
> what you meant by necklaced?

That's the primary, not the alternate. The alternate is on a shorter than
average
hose that comes directly over the right shoulder and is secured under the
chin by
a bungie or sergical tubing necklace. The length of the necklace varies
base on
how close you want the alternate. DIR style keeps it very close, so that,
if necessary,
you can pick it up and use it no hands. Mine is a bit looser, but still
held right where
I can find it every time I want it, in the light, in the clear, in the dark
or in a silt out.
In the picture, the necklaced alternate is the lower of the two regulators.

My necklace is wrapped around the mouthpiece, not hard fastened to the
regulator.
If you, or I, were to grab it and pull hard enough, the necklace would slip
off, but
you'd have to try.

> It looks like a practical way of dealing with a really long hose.

It is surprisingly effective. Interestingly, if you look closely, you'll
notice that all hoses
are quite close to the body at all points. Look at a standard hose
configuration and
you'll realize that the primary hose loops well away from the body above the
right
shoulder. The standard configuration is a much greater entantlement hazard
than the
properly wrapped long hose.

Lee

"Mick" >> Here's an example (note that this is not necessarily an
endorsement of
>> Halcyon, just DIR-L).

> So, the hose comes up under your right arm, across your chest, then
> around behind your neck and over your right sholder, correct? Is this
> what you meant by necklaced?

That's the primary, not the alternate. The alternate is on a shorter than
average
hose that comes directly over the right shoulder and is secured under the
chin by
a bungie or sergical tubing necklace. The length of the necklace varies
base on
how close you want the alternate. DIR style keeps it very close, so that,
if necessary,
you can pick it up and use it no hands. Mine is a bit looser, but still
held right where
I can find it every time I want it, in the light, in the clear, in the dark
or in a silt out.
In the picture, the necklaced alternate is the lower of the two regulators.

My necklace is wrapped around the mouthpiece, not hard fastened to the
regulator.
If you, or I, were to grab it and pull hard enough, the necklace would slip
off, but
you'd have to try.

> It looks like a practical way of dealing with a really long hose.

It is surprisingly effective. Interestingly, if you look closely, you'll
notice that all hoses
are quite close to the body at all points. Look at a standard hose
configuration and
you'll realize that the primary hose loops well away from the body above the
right
shoulder. The standard configuration is a much greater entantlement hazard
than the
properly wrapped long hose.

Lee