HDTenEightyP/NetNews huggingface dataset:
From: spindler@rcf.rsmas.miami.edu
Subject: Re: Mixing O2/N2 for Nitrox
Reply-To: spindler@rcf.rsmas.miami.edu
Organization: RSMAS
Date: Fri, 6 Nov 92 16:41:22 GMT

In article <9211061410.AA18757@cfa.harvard.edu>, 
geary%cfa3.DECNET@cfa.harvard.edu writes:

[stuff deleted]

>\I was taught first you shouldn't
>\homebrew but, if you mix the gas by diffusion it takes from 4 - 5
>\days for the O2 and the air to mix uniformly.
>
>\Therefore, if a diver goes diving later in the same day he has
>\his tanks filled he could be at say 90 fsw. and take a number of
>\breaths of almost pure O2. Since we all know the max depth on pure
>\O2 is around 20 fsw. this could cause some problems in an extreme
>\situation.
>
>No, no, NO !!  Not true.  If IAND is teaching this, it is utter
>garbage.  Do not believe it.  Even under ideal (totally nonturbulent)
>conditions, mixing of O2 and N2 will go very quickly in a tank (few
>seconds).  Add a bunch of turbulence, such as will always be the
>case in a real tank, and the mixing is virtually complete when you
>shut the valve.
>

I beg to differ.  Although it seems to be contrary to my fluid dynamics
background, there actually appears to be a definite mixing time for NITROX in
the tank.   We use a premixed NITROX blend (NOAA NITROX I, I believe), and
boost with pure O2 to get NOAA NITROX II.  But if we fill with successive
pulses from each tank, and then analyze soon afterwards, we get significantly
different concentrations, as though the last fill is sitting at the top of the
mix. It appears as though the gas does stratify, at least for awhile.  We've
found that either letting the tank sit for several hours, or rolling it
vigorously will stir up the contents sufficently to homogenize the mix.

----
Todd Spindler                                  
TSpindler@rsmas.miami.edu                 RSMAS/MPO  University of Miami
From: mayne@phi.cs.fsu.edu (William Mayne)
Subject: Re: Filling Cylinders with Nitrox.
Reply-To: mayne@cs.fsu.edu
Organization: Florida State University Computer Science Department
Date: Mon, 9 Nov 92 17:01:58 GMT

In article <1992Nov07.003730.24419@herboid.uucp> adb@herboid.uucp (Anthony DeBoer) writes:
>
>We discuss a lot of advanced and technical diving techniques here in
>rec.scuba, and the answer has never been "don't talk about it" before. 
>The thing we have always advocated, though, is GET THE PROPER TRAINING.

Absolutely. Finding out as much as possible before making the commitment
to get training and start doing something should be encouraged, not flamed.
I would add that I have learned things in rec.scuba and through research
which started here which weren't included in any of the formal training
I've had. This is especially true of technical matters, since the readers
and contributors of rec.scuba tend to be more scientifically literate than
the average diving instructor. Sometimes I think basic scuba is taught by
and for idiots.
 
>It's lack of information (and misinformed judgement sometimes based on a
>lack of appreciation for the issues involved) that kills people.

Will Rogers said (approximate quotation) "It isn't what we don't know
that gets us in trouble. It's what we know that just ain't so."

Bill Mayne

Newsgroups: rec.scuba
From: mdege@novell.com (Mike Dege)
Subject: Need Bahama info
Organization: Novell, Inc., Provo, UT, USA
Date: Wed, 11 Nov 1992 19:28:24 GMT

Howdy-
   I am going to be diving in Nassau, the Bahamas Dec 29-Jan 5 with my
girlfreind who has been newly certified.  We will be staying at the
Ramada Inn and are diving through Stuarts Cove Dive Shop.  We have
allready laid down our money but would like to know if anyone could
make any suggestions or comments on the following.
 1. What are good dives in the area for a new diver?
 2. Has anyone had experience with Ramada, Stuarts Cove, Good? Bad?
 3. Sights to see on land?
 4. Good and or cheap restaurants ?
 5. Whatever else...

Thanks...
Newsgroups: rec.scuba
From: mayne@phi.cs.fsu.edu (William Mayne)
Subject: Re: US Divers vs Sherwood
Reply-To: mayne@cs.fsu.edu
Organization: Florida State University Computer Science Department
Date: Tue, 10 Nov 92 16:42:38 GMT

In article <BxHvL8.27t@kings.demon.co.uk> russell@kings.demon.co.uk (Russell Brown) writes:
>[Ref. an earlier description of regulator freeze up during an ice dive.]
>No it wasn't a SUPREME, just a regular SE2.  I believe/guess that it was
>the second stage that froze (nothing ruptured from HP air) but can't
>really say for sure as I was more interested in changing valves and
>returning to the exit hole at the time!  By the time I'd got out,
>settled down, turned off the tank valve and started to examine things,
>the second stage was almost completely filled with ice.  I don't think
>that the cylinder had been emptied (10 or 12l @150ish bar at 2-3 meters
>depth) but can't swear that it wasn't - memories blur over the passing
>years :-(

As a warm water wimp who never goes in near freezing water I know
nothing about ice diving. But I am curious. Is it usual in ice
diving to have a redundant air supply like it is in cave diving?
Cave divers normally have two regulators (both first and second
stage) attached to the same tank or set of doubles, so the first
thing to do if there is a free flow is to shut down the valve
feeding the free flowing regulator, hopefully saving most of the
air in the tank for use while getting out. From your description
it sounds as if your regulator continued to flow until you were
out. Cave divers may also have yet another completely independent
air supply, such as a 72 or 80. (Pony bottles are to cave diving
like some people think Spare Air is to open water - too small to
be useful.)

Since ice diving is also an overhead environment I would expect
something similar, though perhaps since you are much closer to the
exit you can get by with a smaller tank for your emergency supply.
I'd also be curious to know how far you get from the exit hole.

Bill Mayne
Xref: sparky rec.scuba:5901 misc.forsale:30501
From: jamesr@Autodesk.COM (James Rowell)
Newsgroups: rec.scuba,misc.forsale
Subject: Scuba Equipment For Sale - SF Bay Area.
Date: 5 Nov 92 23:05:28 GMT
Followup-To: rec.scuba
Distribution: ba
Organization: Autodesk Inc., Sausalito CA, USA

For sale:

    - Dacor XL regulator first and second stage.
    - Princton Tectonics Depth and Pressure gauge.
    - (with that hose thingy that goes to the BC.)
    - White's Men's medium 1/4 inch Lycra wet suit with hood.
    - other misc diving equip.

All equipment in mint condition, used fairly little.

Best offer accepted.
Contact James at (415) 759-7232 (San Francisco)
or e-mail jamesr@autodesk.com
Organization: Carnegie Mellon, Pittsburgh, PA
From: gilbert@CS.ColoState.EDU (brian david gilbert)
Subject: Re: Need Some Advice
Date: Fri, 06 Nov 1992 16:24:20 GMT
Organization: Colorado State University, Computer Science Department

In article <1992Nov6.100930.24719@tfs.com> robw@tfs.com (Rob Woerner) writes:
>$450. !!?  For basic certification??   Way way too much.  Find another
>instructor.

No kidding!  A basic certification costs about $120 plus about $200
for your 4 open water dives (we go to New Mexico for that).  $450 is
outrageous, I would find another instructor!

Brian

-- 
*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= Brian Gilbert =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
* Email: gilbert@cs.colostate.edu     | Comp. Info Specialist & Sys Grunt *
* Email: bgilbert@vines.colostate.edu | Morgan Lib. Colo. State University*
*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
Newsgroups: rec.scuba
From: davew@comm.mot.com (Dave Weigand)
Subject: Re: resort reviews
Reply-To: davew@jdc.gss.mot.com
Organization: Motorola
Date: Wed, 11 Nov 1992 01:45:40 GMT

In article <BxGxzu.JzC@rice.edu>, krentel@cs.rice.edu (Mark W. Krentel) writes:
|> Has anyone been to any of these places and are willing to tell me what 
|> you think of them?  In particular, do they have unlimited shore diving,
|> and is the shore diving any good (or do you really need boats)?  What we
|> usually like to do is dive, dive, dive: go out on boats in the morning, 
|> then pack up the van and do shore dives in the afternoon.
|> 
|>   1. Riding Rock Inn       San Salvadore, Bahamas
|>   2. Off The Wall Divers   Grand Turk
|>   3. Sam McCoy's           Little Cayman
|>   4. Divi Tiara            Cayman Brac 

-- 

I would also be interested in any information or experiences anyone has
had with dive resorts in Grand Cayman.  As well as the above questions
such as shore diving I am also interested in knowing the size of boats
(six-pack or cattle), how many boat dives are in a dive day and if a 
night dive is included during the week.


-Dave

--
+-------------------------------------------------------------------------+
| Dave Weigand                       | Internet:  davew@jdc.gss.mot.com   |
| Senior Electrical Engineer         |     or if you must ...             |
| Japan Digital Cellular Subscriber  | UUCP:      uunet!motcid!weigand    |
| General Systems Sector             | Voice:     (708) 632-2248          |
| Motorola, Inc.                     | Fax:       (708) 632-2044          |
+-------------------------------------------------------------------------+
Newsgroups: rec.scuba
From: dave@hpdstma.ptp.hp.com (Dave Waller)
Subject: Re: Filling Cylinders with Nitrox.
Organization: Hewlett Packard
Date: Fri, 6 Nov 1992 19:10:14 GMT

In article <lfiq0kINN8gq@news.bbn.com>, wall@hel4.brl.mil writes:
|> 
|> I have taken the NITROX class (IAND) but I have not done my dives and recieved
|> my card.  The impression I got from class was that filling a tank with a higher
|> percentage O2 was not necessarily the problem.  The problem came when divers
|> put in the pure O2 took the tank to the dive shop to be filled and then went
|> diving later that day.  I was taught first you shouldn't homebrew :-) but, if
|> you mix the gas by diffusion it takes from 4 - 5 days for the O2 and the air to
|> mix uniformly.

Interesting. Do you have a credible source for this information? I have a
pretty good background in physics, and from what I understand about gases,
this is simply not true. Gases, unlike liquids, do not separate due to density
differences after mixing, and due to the their highly fluid nature, it is
_extremely_ difficlut to place two gases in proximity of each other and not
have them mix. If they did, then simple air sitting in a tank in your garage
would separate into O2 and N2, and would suffer from the same time dependent
mixing problem that you are asserting above. Of course, we all know that this
is not the case.

Absent some compelling evidence/explanation from a credible scientist, I
would say that whoever told you this was grossly ill-informed (which seems
to be a pervasive problem in the SCUBA instructional community when it
comes to technical matters).

-- 
Dave Waller
YMCA Instructor
From: elacey@sw.stratus.com (Eric Lacey)
Newsgroups: rec.scuba
Subject: Re: Need Some Advice
Date: 6 Nov 92 19:48:51 GMT
Organization: Stratus Computer, Inc.

In article <Nov06.162420.66868@yuma.ACNS.ColoState.EDU>, gilbert@CS.ColoState.EDU (brian david gilbert) writes:
> In article <1992Nov6.100930.24719@tfs.com> robw@tfs.com (Rob Woerner) writes:
> >$450. !!?  For basic certification??   Way way too much.  Find another
> >instructor.
> 
> No kidding!  A basic certification costs about $120 plus about $200
> for your 4 open water dives (we go to New Mexico for that).  $450 is
> outrageous, I would find another instructor!

I got my certification and did my open water dives in Mass, and I only paid $150
for the entire course, dives included...

Eric
From: gd@gehenna.sw.stratus.com (Greg Dawe)
Newsgroups: rec.scuba
Subject: Re: The Cost of OPENWATER I
Date: 10 Nov 92 14:47:39 GMT
Organization: Stratus Computer, Software Engineering
NNTP-Posting-Host: gehenna.sw.stratus.com

In article <1992Nov9.184741.13570@newssun.med.miami.edu> dbrown@newssun.med.miami.edu (Daniel Brown) writes:
>Recently I read several articles about a student's "tuition" for his SCUBA 
>class: $450,...
>
>...  Suppose the student above were taking a private class, what would he be 
>paying an hour? ...
>
>Dan Brown

Dan, you raise an important point that was overlooked by the original 
responders.  There are all kinds of different ways to offer SCUBA
instruction, and the fees vary accordingly.  As an instructor, I am paid
differently, depending on the wishes of the student.

The diveshop I work for offers "public" and "private" instruction.  The public
classes are scheduled months in advance, have a standard, low-end price, and 
have between 4 and 18 students.  Private classes are at the specific request
of a student, or small group of students (a family, or some close friends)
and are scheduled specifically for the student's convenience, hence a more
premium price.
-- 
Greg Dawe                        | Disclaimer: I don't speak for my employer,
Voice : (508)-490-6666           |             nor they for me...
e-mail: Greg_Dawe@vos.stratus.com|            
Newsgroups: rec.scuba
From: kosicki@ratchet.Prime.COM (Bernie Kosicki)
Subject: The Cost of Diving
Reply-To: kosicki@ratchet.Prime.COM (Bernie Kosicki)
Organization: Prime Computer R&D
Date: Thu, 12 Nov 1992 13:46:21 GMT


Unfortunately I missed the discussion regarding the costs of diving
versus other high priced sports.  I read Alan Wrights post, and I have
to add some personal experience to this.  When I was getting certified,
I had a rather lengthy discussion with the instructor in which I felt
that diving was quite a bit more expensive that skiing ( I do a lot of
skiing in the winter).  Since then I have reversed my thinking on this. 
The equipment costs for scuba, although high, are rather long term in
nature.  A good pair of skis goes about $500 - $700 with bindings
included.  Some people eat up skis at a pair a year.  I personally have
been going about 3-4 years per pair.  How long does a BCD and regulator
set last? Maybe 10+ years, especially with the warantee and service
contracts from the manufacturer.   On top of that, to make a 2 tank
shore dive costs about $6 dollars for air, plus your lunch expenses (and
parking tickets :-)  ).  A full-day adult lift ticket here in New
England costs $35 - $45 dollars.  And try buying food at a ski lodge. 
So I think the start up costs are in fact higher, but when you look down
the road it actually becomes a great deal.  Also I have never had an out
of control diver run into me at high speeds.

Sorry if this has been repetitious.

Bernie Kosicki
From: wall@hel4.brl.mil
Newsgroups: rec.scuba
Subject: Re: Filling Cylinders with Nitrox.
Date: 5 Nov 92 18:29:40 GMT
Organization: U.S. Army Human Engineering Lab
NNTP-Posting-Host: bbn.com

In article <1992Nov5.054757.3583@panix.com> fhd@panix.com (Frank Deutschmann)
writes:
>
>My appologies for the suicide line, and the overly dramatic and rather
>heated post. 
 
Hey we all get excited when we read something we don't agree with. :-)

>However, some clarification is in order.  First, this "homebrew
>NITROX" thread started with a person with absolutely no exposure to
>NITROX whatsoever asking how to do homebrewing (with what seemed like
>serious intent to try it, with no mention of getting any real
>training).  This really concerns me, because I am a NITROX diver (took
>the ANDI course in March, and have done lots of dives with NITROX
>since then) and pressure against NITROX has been really mounting in
>my area (Long Island) lately -- now is an especially bad time for any
>NITROX-related accidents.  Last year there was a CO poisioning death
>blamed on homebrew, and this year I believe that we had three
>accidents (don't have the references, and may be wrong).

I have taken the NITROX class (IAND) but I have not done my dives and recieved
my card.  The impression I got from class was that filling a tank with a higher
percentage O2 was not necessarily the problem.  The problem came when divers
put in the pure O2 took the tank to the dive shop to be filled and then went
diving later that day.  I was taught first you shouldn't homebrew :-) but, if
you mix the gas by diffusion it takes from 4 - 5 days for the O2 and the air to
mix uniformly.

Therefore, if a diver goes diving later in the same day he has his tanks filled
he could be at say 90 fsw. and take a number of breaths of almost pure O2. 
Since we all know the max depth on pure O2 is around 20 fsw.this could cause
some problems in an extreme situation.

I also admit this could be a rare and and unusual situation but I wanted to
mention it because no one else had.

Jeff Wall
wall@hel4.brl.mil
Newsgroups: rec.scuba
From: billp@sco.COM (Jerque Clumsoe)
Subject: Re: Night Diving Tips
Organization: The Santa Cruz Operation, Inc.
Date: Fri, 13 Nov 1992 16:45:55 GMT


In article <1992Nov4.145151@is.morgan.com> scairns@is.morgan.com (Scott Cairns) writes:
>My question is a couple of the more adventourous divers in our group
>want to do some night dives, particularly on the wreck of the Rhone.
>Those who want to do try this have a night dive or two under their
>belt but only on guided tours.   I've purchased a strobe light for 
>marking our descent line but that's about all we've done to prepare
>for this experience.  Yes, we have flashlights.
>
>I'd like to know some other suggestions or helpful hints that the net
>can suggest for novice night divers.  We're only going to do night dives
>that we've dove in the daylight (hence the Rhone - I've done it at
>least a dozen times) and where we can tie up to a mooring bouy for
>use as a descent line.   Any info will be appreciated.
>

Night Dives. A couple things off the bat that help. Besides the flashlights,
it's a good idea to have cylumes glow sticks that you can tape on your
snorkel. They're a good safety tip since you'll be visible from far away.
They come in different colors, so this is nice way to tell who
is who down there. I like to shine my light on my console before getting
in so it glows nicely without the light during the dive. Naturally, avoid
shining your light on your buddies face, otherwise, they won't see a thing
for a minute or so. I like to give hand signals with the light behind
my signal so that it's easy to make out. If there's trouble, a good signal
is to make a giant "X" with the flashlight. If the bio-luminesence is
good, it's fun to turn off your flashlights for part of the dive. You'll
still be able to see where everybody is via the cylumes. That should do it!

-mr.billp
 NAUI #11211

 
-- 


    "What's all this gear for?" He asked. "For Scuba Diving," I told him.
    "Scuba Diving?" He looked outside at the snow, then back at me.
    "Wait, don't tell me. You're from California, right?"
Newsgroups: rec.scuba
From: lls@kings.demon.co.uk (Lady Lodge Systems)
Subject: Re: US Divers vs Sherwood
Organization: Lady Lodge Systems
Date: Fri, 6 Nov 1992 14:04:45 GMT

In article <1992Nov5.223351.25606@ultb.isc.rit.edu> mstacc@ultb.isc.rit.edu (M.S. Tremblay) writes:
>In article <100645@bu.edu> cigliano@bu-bio.bu.edu (John Cigliano) writes:
>>I have been looking at regulators and have narrowed my choice to either
>>the US Divers SEA2 or the Sherwood Oasis. Most of my diving will be cold
>>water (S. Cal and New England).
>>
>Most people in our area now dive pretty much on Poseidon's.

Just one little data point from personal experience:  I've had a
Conshelf SE2 freeze and free-flow on me whilst ice-diving.  My
Poseidon's have never done that despite more ice-dives whilst using
them.
-- 
Regards,
        Russell
 ---------------------------------------------------------------------------
| Russell Brown          | MAIL : russell@kings.demon.co.uk                 |
| Lady Lodge Systems     | PHONE: 0832 272224 (Home/Work it's all the same) |
| demon.co.uk is an Internet access point for zillions of unrelated systems |
 ---------------------------------------------------------------------------
Newsgroups: rec.scuba
From: adb@herboid.uucp (Anthony DeBoer)
Subject: Ice Diving (was Re: US Divers vs Sherwood)
Organization: Linda's Dragon Memorial Society
Date: Thu, 12 Nov 1992 01:46:49 GMT

Bill Mayne <mayne@cs.fsu.edu> writes:
>As a warm water wimp who never goes in near freezing water I know
>nothing about ice diving. But I am curious. Is it usual in ice
>diving to have a redundant air supply like it is in cave diving?

If you've got it, you wear it, but I've seen a lot of ice divers without
redundant air supplies.

>I'd also be curious to know how far you get from the exit hole.

The usual rig, from my club, that we use ice diving has 100' lines. 
There's a 150' safety diver line, which (thank God) we've never had to
use.  The other set I've used had 50' diver lines.

That theoretically limits you to a hemisphere centred on the exit hole,
of a radius maybe 10' less than the length of the line by the time you
account for it running from the surface anchor point, through your
tender's hands, into the hole, and down to the shackle on your harness. 
In practise, the bottom is usually a bit shallower, and you try not to
allow the line to get around any bottom obstructions or around your
buddy's line too many times.

On the emergency signal, three or more tugs from the diver, the tender is
supposed to start hauling for all he's worth.  (The quick way is to take
the line over your shoulder and jog away from the hole, but there's a
danger of banging the diver's head doing that :-) ).  Most freeflows
won't be done flowing yet by the time you're flopping out onto the ice
again.
-- 
Anthony DeBoer   NAUI # Z8800, D5482 | Why watch TV, when Netnews provides
adb@herboid.uucp | adb@geac.com      | 100% of your daily requirement for
uunet!geac!herboid!adb               | trivia and meaningless entertainment?
From: craig@cattnts.canada.ncr.com (Craig Campbell)
Newsgroups: rec.scuba
Subject: Re: Helmet-mounted dive lights
Date: 10 Nov 92 13:14:12 GMT
Organization: AT&T / NCR Canada Ltd., Toronto, Canada

In article <7972@transfer.stratus.com> gd@gehenna.sw.stratus.com (Greg Dawe) writes:

>Wearing the mask strap inside the hood has many advantages and disadvantages.
>On the plus side the mask can't be knocked off your face during a backwards
>roll - or by a panicked diver during a surface or submerged rescue.  Sure, it
>can be displaced and unseated, but not knocked-off completely.  So it can be
>argued to a small degree that a spare mask isn't needed it you can't lose 
>the one you're wearing.

Actually, I have never heard of the spare mask argument being used ofr a 
lost mask (although it makes sense).  The argument I was presented with is
a broken mask.  I have heard of masks 'spontaneously' breaking during a dive.
Obviously, in a cave system, this would be extremely nasty.

>BTW, I'm considering wearing my spare mask around my neck, with the mask
>facing backwards, but I haven't tried this out yet.  I can see the primary 
>disadvantage in that you've got to take the second stage out of your mouth
>before you seat the mask - something that may prove to be unadvised, but I'm
>going to try it out first.  Where do you carry your spare?  Many of my partners
>are cave certified, and they carry their spare in various places, like over the
>top of a battery pack etc - configurations that seem appropriate to the cave
>environment, but not so good in open water where they might be knocked off.
>I've yet to see a carrying place as secure as around the neck (BC pockets
>aren't an option, since none of us have any).

I've tried around the neck, but so far find it far too uncomfortable.  I've
seen a mask worn backwards around the back of the head, but never tried it.
I have a Dive-Right Pocket, and my (smaller) spare mask fits well into 
the largest compartment.  It is a real b*tch to get to with those mits on
though.  So far I've been lucky and never REALLY needed it.

>Greg Dawe                        | Disclaimer: I don't speak for my employer,

craig

P.S.  Let me know if you come up with a really GOOD location for your mask.

c.e.c.

-- 
Craig Campbell		|	These opinions are entirely the result of a 
Systems Engineer	|	small butterfly crashing into the far side
NCR Canada,		|	of the planet.  Chaos Rules.
an AT&T Company		|	I speak for no one, except, possibly, myself.
Newsgroups: rec.scuba