A few ???'s
William Mayne
>...
>-What exactly is a "first stage" and a "second stage"?
> I _think_ one is the small metal clamp that attaches to the top of the
> tank, and the other is the actual mouthpiece, but often I have seen TWO
> mouthpieces on divers in pictures. (One in mouth, one dangling free.)
Well, the first stage does attach to the tank, but it is more than a little
metal clamp. It lets air out of the tank and into low pressure hoses (at
about a constant 150 p.s.i.) in a controlled way. Similarly the second
stage is built in to the mouthpiece, but it too is a demand regulator,
taking as input the 150 p.s.i. from the first stage and delivering air
at ambient pressure for breathing. Its not just a mouthpiece.
>-How does an "Octupus" fit into the "first-and-second-stage" stuff?
> I'm pretty sure that an Octopus is the common name for the
> dangling-free mouthpiece, but not completely sure.
The octopus is an alternate second stage. It should not be dangling free,
though. It is used in an emergency, normally to share air with a buddy
who may be having trouble, occassionally just to even out air consumption
is one person has less than his or her buddy - or for practice, of course.
It should be secured somehow within easy reach. (I'm a cave diver and we
try not to have anything dangling, not even gauges. This is a good practice
for open water diving as well, though, as you have noted in photographs,
it is not always practiced.)
>-Why is there a mouthpiece on the hose dangling from a bouyancy-control vest?
Usually to allow blowing up the BC by mouth. Sometimes there is a second
stage built in so it can also be used to breathe from instead of an octopus.
>-Is it better to have the depth and pressure gauges on a hose, attached to the
> tank, or separate (strapped to a wrist, etc)?
Personal preference. It is slightly easier to check gauges attached to
the wrist, especially if your hands are full, but a separate depth
gauge is one more piece of equipment you have to keep track of.
> Or, What sort of gauge would one want on the hose and what on the wrist?
The pressure gauge obviously must be attached to the tank by a hose, though
you might attach it your wrist as well. A depth gauge doesn't need to be
attached to the tank and is more likely to be worn on the wrist.
>Pretty simple questions, but they are things I never guite got the hang of.
>I feel like the student with the stupid question, but every other student
>needs to know the answer to it, so it's better to ask it.
If you learn too much ahead of time, or if your IQ is more than 50 you
may find your class unbearably boring. :-( It gets better after your
basic certification class, though.
>I also wear glasses, so I may go with a prescription mask discussed a few
>weeks earlier on the list. Thanx to any and all!
By all means get a prescription mask unless you can see pretty well, say
well enough to drive, without glasses. Seeing is a large part of the fun.
Don't skimp on a mask.
Bill Mayne (ma...@cs.fsu.edu)
M. J. Saltzman
>Hello Divers,
>
> I have been following this list for a while, even though I am not
>a certified diver myself. I've done a lot of snorkelling, and I hope to take
>my NAUI certification course next semester at Whitman, so hopefully I
>won't be above water too much longer. I have two back issues of Skindiver
>magazine that I've been browsing, and there are some things I am confused
>about. A little explanation would go a long way here.
>
>-What exactly is a "first stage" and a "second stage"?
> I _think_ one is the small metal clamp that attaches to the top of the
> tank, and the other is the actual mouthpiece, but often I have seen TWO
Exactly right.
> mouthpieces on divers in pictures. (One in mouth, one dangling free.)
Which brings us to your next question:
>
>-How does an "Octupus" fit into the "first-and-second-stage" stuff?
> I'm pretty sure that an Octopus is the common name for the
> dangling-free mouthpiece, but not completely sure.
Right again! It's an auxiliary second stage, for your buddy to breath
off of in an emergency (he/she is out of air, equipment failure, etc.).
>
>-Why is there a mouthpiece on the hose dangling from a bouyancy-control vest?
To allow you to inflate/deflate your BC (that's what bouyancy control
is all about). This is usually also connected to the first stage of
your regulator, so you can inflate from your tank by just pressing a
button.
>
>-Is it better to have the depth and pressure gauges on a hose, attached to the
> tank, or separate (strapped to a wrist, etc)?
> Or, What sort of gauge would one want on the hose and what on the wrist?
>
A pressure guage tells you how much pressure there is left in your tank.
It only makes sense to ahve it on a hose. The other guages can be
carried wherever you find most convenient. (I prefer the "console"
attached to the tank, myself.)
>Pretty simple questions, but they are things I never guite got the hang of.
>I feel like the student with the stupid question, but every other student
>needs to know the answer to it, so it's better to ask it.
Definitely. Can I tell my students you said so?
>
> Thanks for any answers, and Happy Diving!
>
A pleasure. Good luck in your course, and welcome to rec.scuba.
> Kevin Judson
> JUDSONKM@WHITMAN
Matthew Saltzman
m...@clemson.edu
>
>P.S. - I may need to get a mask, fins, snorkel, gloves, and booties
>for the class next year. Are there any suggestions for dive shops in
>the Northwest - specifically Seattle, Bellevue, and Tacoma, etc?
>And, as well, any suggestions for good masks, fins, etc? I also wear
>glasses, so I may go with a prescription mask discussed a few
>weeks earlier on the list. Thanx to any and all!
These are all highly personal decisions. Some pointers (really basic--
your instructor will give you the same advice): Get a
low-volume mask. Get open-back fins rather than the full foot pocket.
Don't get a blade that's too large/small/stiff/ flexible. Get boots
with a wrap-around hard sole. If you get prescrip. lenses, you might
find you like the masks with a split faceplate over those with the
full-width faceplate. Above all, get what feels comfortable, and don't
worry too much about getting high-tech whiz-bang stuff (especially fins).
M. J. Saltzman
In article <910415205...@news.UU.NET> I wrote:
>In article <910414002...@relay1.UU.NET> a new diver wrote:
>>Hello Divers,
>>
>> I have been following this list for a while, even though I am not
>>a certified diver myself. I've done a lot of snorkelling, and I hope to take
>>my NAUI certification course next semester at Whitman, so hopefully I
>>won't be above water too much longer. I have two back issues of Skindiver
>>magazine that I've been browsing, and there are some things I am confused
>>about. A little explanation would go a long way here.
>>
>[His questions and my responses deleted]
I meant to e-mail directly to the questioner, but I got bit by the
SCUBA-L return address. I like Bill Mayne's responses better anyway,
but now I can't cancel my article, since it was posted by SCUBA-L.
Oh, well...
Matthew Saltzman
m...@clemson.edu
Kevin Klop
>
> I have been following this list for a while, even though I am not
>a certified diver myself. I've done a lot of snorkelling, and I hope to take
>my NAUI certification course next semester at Whitman, so hopefully I
>won't be above water too much longer. I have two back issues of Skindiver
>magazine that I've been browsing, and there are some things I am confused
>about. A little explanation would go a long way here.
>
> I _think_ one is the small metal clamp that attaches to the top of the
> tank, and the other is the actual mouthpiece, but often I have seen TWO
The first stage is the part of the regulator that reduces the tank pressure
down to about 100 lbs above "ambient" pressure. The second stage is the part
of the regulator that reduces the 100lbs over ambient to ambient pressure.
Ambient pressure is the sum total PSIs exerted on your body. At sea level,
that's one atmosphere. At 10 meters, it's 2 atmospheres.
Most modern systems has the first stage clamped onto the tank, and the second
stage in your mouth. That mouthpiece that you see dangling is AlSO a second
stage.
The second mouthpiece ties into the next question - I'll answer it there.
>
>-How does an "Octupus" fit into the "first-and-second-stage" stuff?
> I'm pretty sure that an Octopus is the common name for the
> dangling-free mouthpiece, but not completely sure.
The second mouthpiece (often called an "octopus") is for use when your BUDDY
can not breathe off his tank (out of air, malfunction, had to ditch it, etc.)
It is thought to be "safer" than buddy breathing since each person then has
their own regulator and there's no transitions from "my breathing" to "your
breathing".
>
>-Why is there a mouthpiece on the hose dangling from a bouyancy-control vest?
That's the manual inflator. You take a breath from your regulator, remove
your regulator, and breath into the BC mouthpiece. It also is used to
purge air from your vest while diving, and for removing the accumulated
water that inevitably finds its way into the vest after diving.
>
>-Is it better to have the depth and pressure gauges on a hose, attached to the
> tank, or separate (strapped to a wrist, etc)?
> Or, What sort of gauge would one want on the hose and what on the wrist?
Ummm, it's not possible to have a pressure gauage that's not connected to your
tank ;^)
As to the other guages, that's often a matter of choice. Personally, I like
all my guages in one place so that I don't have to look all over for them -
I can sweep my eyes across them all in one motion. However, I know a lot of
people that like arm mounted guages. My console looke like this:
---------------
/ \
| ____ |
| / \ |
| | Depth| |
| | | |
| \____/ |
| |
| ____ |
| / \ |
| | | |
| |Pressure |
| \____/ |
| |
\________________/
| |
| | Hose to tank
On the back side, in the same location as the depth guage is on the front
side, is my compass.
>
>Pretty simple questions, but they are things I never guite got the hang of.
Hey, knowledge is safety in this sport - we can't ever make it 100% safe,
t we can do our best to reach that. Don't worry about asking questions.
>I feel like the student with the stupid question, but every other student
>needs to know the answer to it, so it's better to ask it.
>
> Thanks for any answers, and Happy Diving!
>
> Kevin Judson
> JUDSONKM@WHITMAN
>
>P.S. - I may need to get a mask, fins, snorkel, gloves, and booties
>for the class next year. Are there any suggestions for dive shops in
>the Northwest - specifically Seattle, Bellevue, and Tacoma, etc?
>And, as well, any suggestions for good masks, fins, etc? I also wear
>glasses, so I may go with a prescription mask discussed a few
>weeks earlier on the list. Thanx to any and all!
--
Kevin Klop {uunet|rutgers|amiga}!cbmvax!kevin
Commodore-Amiga, Inc.
The number, 111-111-1111 has been changed. The new number is:
134-253-2452-243556-678893-3567875645434-4456789432576-385972
Disclaimer: _I_ don't know what I said, much less my employer.
David Duis
>
> You don't EVER breathe from your BC.
Unless of course, you're out of air, have practiced this carefully,
have not detonated a CO2 cartridge into your BC, and are using the BC
bladder as a primitive rebreather, by using it as dead space much as
one would a plastic bag on the surface.
This works (for a while) because exhaled air still contains ~16%
oxygen, down from ~21% oxygen on inhalation.
Cheers,
Dave Duis NAUI AI Z9588, PADI DM 43922, EMT
du...@bent.esd.sgi.com Better diving through drugs.
Nicholas J. Simicich
> >
> > You don't EVER breathe from your BC.
>
Don't forget the (required for liability reasons) have cleaned the BC
carefully to insure that no bacteria are living in it. Lung
infections may otherwise result.
I refer you to "Scuba Life Saving", by Albert Pierce, for an
explanation of why this technique is important. You might also have a
regulator failure, but might be able to use your inflator to put air
into your BC, breathe it from your BC, and blow it out your nose, but
I'd consider this an emergency technique, probably not one that you'd
practice, but one that you'd think about.
Perhaps the original answer was at the right level, considering the
original poster.
Nick Simicich (NJS at WATSON, n...@watson.ibm.com) -SSI AOWI #3958, HSA #318
Words of wisdom from Zippy:
Yow! Am I in Milwaukee?
Nicholas J. Simicich
>My initial reaction to Kevin's remark
>
>> You don't EVER breathe from your BC.
>
>by Duis and Simicich. Nick, however, made the ancilliary comment
>
>> Perhaps the original answer was at the right level, considering the
>> original poster.
>
>unlikely to be of any help to the original poster (beginner or not, he is
>going to breathe from his regulator, with or without the remark) while it is
>likely to mislead the average or advanced divers into overlooking some VERY
>IMPORTANT advanced diving techniques -- among which, breathing from the BC is
>an important technique for emergency ascent, though it is generally (note that
>I suppressed the urge to say "never") not taught in any Open Water or advanced
>scuba courses.
My remark was flip, and I agree with your accessment.
>Another better-known NEVER (equally wrong; but IS taught at courses) is, in
>scuba-diving, "NEVER hold your breath underwater". The advanced technique for
>buoyancy control in a slow ascent is through proper breath control -- which
>includes HOLDING YOUR BREATH (albeit BRIEFLY, at a NEARLY CONSTANT DEPTH,
>usually AFTER EXHALATION) to achieve the proper rate of ascent via breath
>control.
Here we disagree, but perhaps it is a matter of semantics. I teach my
students that "holding your breath" is a matter of closing your
glottis, whereas that differs from "not breathing" where you are just
not expanding or contracting your chest for a moment, but your airway
is open.
Holding your breath, by my definition, is the dangerous activity. Not
breathing is much less of a problem.
The reason I still believe that "never hold your breath" is a good
idea is that it is just a bad habit to get into. I think that if you
learn to hold your breath on descent, eventually you will hold your
breath on ascent, whereas if you learn to keep an open airway, you
will probably be OK.
--
Nick Simicich - uunet!bywater!scifi!njs - n...@watson.ibm.com
SSI #AOWI 3958, HSA 318
Anthony DeBoer
>I left something out of the explanation of the mouthpiece on the BC...
>
>mouthpiece, then you remove the BC Mouthpiece, re-insert your second stage
>into your mouth, purge the water from your second stage, and take a breath.
>You don't EVER breathe from your BC.
That's if you use a CO2 emergency inflator on your BC, that you don't ever
breathe from it. Breathing carbon dixoxide gets bad for you real fast. (The
other problem you can run into is with stuff growing inside your BC getting
into your lungs, but you have a lot more time to seek treatment for that than
you would for, say, cerebral air embolism, so you'd really want to optimize
your emergency ascent procedure to avoid embolism and to xxxx with everything
else).
Undercurrents magazine ran an article awhile back on using the BC on an
emergency out-of-air ascent. In their humble opinion, it was a viable option,
so long as CO2 wasn't involved. I don't know if I'd do it myself, as I'd lean
towards keeping my regulator mouthpiece and breathing in and out on it as much
as it would let me. But the key idea is that if you can keep breathing in and
out the whole way up, you won't get embolized. And with the percentage of the
oxygen than we breathe in that we don't actually use, but breathe out again
(which is why mouth-to-mouth rescuation works), you actually get something
from the exhaled air you breathe again. Trying to exhale the whole way up
doesn't work as well, according to Dr. George Harpur, who runs the Tobermory,
Ontario hyperbaric chamber.
There are also BC's like the Fenzi and some other British brands than include
a small pony bottle on the bottom of the BC. In an emergency you crack it
open and the BC fills right up and starts popping the overflow. Then you
breathe clean air off the BC oral inflator hose the whole way up.
--
Anthony DeBoer NAUI#Z8800 | ade...@gjetor.geac.com | Programmer (n): One who
Geac J&E Systems Ltd. | uunet!geac!gjetor!adeboer | makes the lies the
Toronto, Ontario, Canada | #include <disclaimer.h> | salesman told come true.
Robert F. Ling
> You don't EVER breathe from your BC.
was the oxymoronic phrase, "NEVER say NEVER", for reasons expounded in replies
by Duis and Simicich. Nick, however, made the ancilliary comment
> Perhaps the original answer was at the right level, considering the
> original poster.
to which I disagree for the reason that the original "don't EVER" remark was
unlikely to be of any help to the original poster (beginner or not, he is
going to breathe from his regulator, with or without the remark) while it is
likely to mislead the average or advanced divers into overlooking some VERY
IMPORTANT advanced diving techniques -- among which, breathing from the BC is
an important technique for emergency ascent, though it is generally (note that
I suppressed the urge to say "never") not taught in any Open Water or advanced
scuba courses.
Another better-known NEVER (equally wrong; but IS taught at courses) is, in
scuba-diving, "NEVER hold your breath underwater". The advanced technique for
buoyancy control in a slow ascent is through proper breath control -- which
includes HOLDING YOUR BREATH (albeit BRIEFLY, at a NEARLY CONSTANT DEPTH,
usually AFTER EXHALATION) to achieve the proper rate of ascent via breath
control.
The bottom-line of my discussion is that "don't EVER" or "never" need not be
used unless it means NEVER (under any circumstance), especially if some of the
circumstances that call for the violation of the "never rule" turn out to be
necessary or beneficial. If I am forcibly kept underwater until I make a
statement in which the use of "never" is appropriate, I might offer something
like, "NEVER cut your own throat underwater if you have the desire to live".
:-)
-- Bob.
Dave Waller
>
> >Another better-known NEVER (equally wrong; but IS taught at courses) is, in
> >scuba-diving, "NEVER hold your breath underwater". The advanced technique for
> >buoyancy control in a slow ascent is through proper breath control -- which
> >includes HOLDING YOUR BREATH (albeit BRIEFLY, at a NEARLY CONSTANT DEPTH,
> >usually AFTER EXHALATION) to achieve the proper rate of ascent via breath
> >control.
>
> students that "holding your breath" is a matter of closing your
> glottis, whereas that differs from "not breathing" where you are just
> not expanding or contracting your chest for a moment, but your airway
> is open.
>
> Holding your breath, by my definition, is the dangerous activity. Not
> breathing is much less of a problem.
>
> The reason I still believe that "never hold your breath" is a good
> idea is that it is just a bad habit to get into. I think that if you
> learn to hold your breath on descent, eventually you will hold your
> breath on ascent, whereas if you learn to keep an open airway, you
> will probably be OK.
I must strongly thow in my agreement here with Nick. Buoyancy via
lung volume should never be used to control an ascent, for several
reasons:
1) There are no nervous receptors in the lung tissue to detect
an overexpansion condition, therefore a diver will have no
warning that they are in danger of rupturing alveoli, and
therefore suffering an embolism. Note that isolated areas
of the lungs can rupture quite a bit before a diver gets
the overall feeling that their lungs are "too full".
2) As Nick points out, repeatedly using this mechanism will
lead to habituation, and such habits can be very dangerous.
Imagine holding your breath while ascending, and then
finding that for some reason air will not evacuate from
your BC -- it is VERY easy to forget you are holding your
breath (although you continue to do so) while your
attention is focused on this other problem, and you
continue to ascend at an ever increasing rate due to the
expansion of the air in your BC. This spells air embolism.
3) With practice, an ascent can much more easily be controlled
by kicking with your fins than it can with lung volume.
Do not ever hold your breath during an ascent. If you take a look at
air embolism stats, you'll find that most of them happen during ascent
(when else?), and they are due to improper breathing techniques. The
method that is taught in openwater classes is the safest, and probably
the most controllable way to ascend -- empty your BC, and use your
legs to control your ascent. Assuming that you have proper weighting,
this should not be difficult. Even if it is (i.e. suit compression
has resulted in significant negative buoyancy), a diver can compensate
for this by adjusting the air in their BC to be neutral at the bottom,
and then let air out durig the ascent in order to maintain neutral
buoyancy throughout the ascent; then, kicking is relatively
effortless.
This method can be learned easily, and is quite controllable. There
is no reason to risk your safety in the manner described above.
Dave Waller
WVANDE...@bentley.bitnet
it, it can be a very effective alternate air source in an emergency. (not
for anyone who hasn't practiced the technique ahead of time though)
Russell Brown
>
>There are also BC's like the Fenzi and some other British brands than include
>a small pony bottle on the bottom of the BC. In an emergency you crack it
>breathe clean air off the BC oral inflator hose the whole way up.
Very few UK Divers use CO2 inflation (it's actually banned in our
branch of the BSAC) but use the 0.8l (ish) cylinders as the emergency
inflation on the ABLJ (BC) or STAB.
FYI - one British manufacturer (Buddy) fit a neat mouthpiece onto their
jackets that actually does let you breath fairly normally from the
jackets air (I've tried one at 30 meters and although strange it worked
well).
Happy Diving.
PS. Did my request for info on DUI's combined inflator/deflator dry suit
valve make it out? I didn't receive any replies :-(
------------------------------------------------------
| Russell Brown | Telephone: |
| Lady Lodge Systems | Office - 0733 239445 |
| Lady Lodge House | Home - 0832 272224 |
| Orton Longueville | EMAIL: rus...@kings.co.uk |
| Peterborough, PE2 0HZ | ...!mcvax!ukc!kings!russell |
------------------------------------------------------
David Duis
>
>PS. Did my request for info on DUI's combined inflator/deflator dry suit
>valve make it out? I didn't receive any replies :-(
>
I thought I'd replied, but I guess it didn't make it, so I'll post
here.
I haven't seen the combined valve you mention, either in catalogs or
at DEMA.
Further, from my experience with a Viking drysuit, I'd consider a
combination valve in the chest location you are seeking to be a bad
idea. The vent has to be at or near the top of your body to be able
to vent all of your air on ascent, so putting it in the chest would be
a bad idea.
However, it is common for neoprene drysuits (a la Monterey Bay
Wetsuits) to have a power/oral-inflator (a la modern US BCs) in the
normal chest location, which could be used to vent air as well as add
air.
Hope this helps.