HDTenEightyP/NetNews huggingface dataset:
From: kehler@dcs.glasgow.ac.uk (Carsten Kehler Holst)
Newsgroups: rec.scuba
Subject: Re: Nitrox (Was Re: Thermodynamic Decompression)
Date: 20 Aug 92 10:00:13 GMT
Organization: Glasgow University Computing Science Dept.




DISCLAIMER: I "know" nothing about Nitrox. This is just my naive 
understanding of the matter.

mayne@ds1.scri.fsu.edu (Bill Mayne) writes:

>The extreme positions are (1) using nitrox just like air and (2) going to
>the nitrox limits, or at least calculating what you do, including padding,
>based on equivalent air depths. Obviously, as you say, the best safety
>factor (short of using an air schedule and then padding that, which gets
>ridiculous) comes from the first method. Sometimes at least a compromise
>between the extremes may be appropriate. From what I understand there are
>physiological and safety advantages to nitrox even if used with equivalent
>air depth for calculations. These include:

>(1) Slight reduction in narcosis - not likely to be a big factor at the
>    relatively shallow depths where nitrox is used.

>(2) Staying in safer regions of the tables, with better repetive groups
>    for repetive diving, if the dive drives the decompression schedule
>    rather than the other way around.

>(3) Faster nitrogen elimination during decompression or safety stops,
>    which is a benefit ignored by the air tables and the NOAA
>    nitrox tables. (Correct me if I am wrong about the latter, but
>    I'm pretty sure this is correct. I know this is true for some
>    profiles.)

>(4) Direct benefit to using higher percentage of oxygen as opposed to
>    the primary benefit of reducing the percentage of nitrogen.


1) My understanding is that when diving on Nitrox, say 32% O_2, 68% N_2,
   the partial pressure of N_2 is reduced 68/79 = 0.86, so being at depth
   d on Nitrox is like being on depth D = d*0.86-1.4 on normal air.

This makes (1) and (2) clear, but doesn't explain claim (3). I don't 
understand claim (4) either. Are there something I have missed? What 
I'm asking is: Are there any factor (bubble size, bubble formation) 
that explain claim (3)?

2) Please explain the term Nitrox decompression. Does it "just" mean diving
   on a Nitrox blend (thereby allowing you to use the reduced equivalent
   depth described above when doing decompression). Or does it, as I
   have been (mis)lead to understand mean diving on air and then switch
   to Nitrox blend when doing decompression stop. Because unless my 
   understanding is wrong that seems to be the completely wrong thing
   to do - though it sounds a little like claim (3).


Carsten Kehler Holst
Diving with Glasgow University Sub-Aqua Club
-- 
----------------------------------------------------------------------
N. Carsten Kehler Holst * kehler@dcs.glasgow.ac.uk * Dep. of Comp Sci.
  The University,  Glasgow G12 8QQ, SCOTLAND  *  Tel 041 339 8855 
   Privat: 51 Rupert St 2/R, Glasgow G4 9AP  *  Tel 041 332 2467 
Newsgroups: rec.scuba
From: wsun@undergrad.math.waterloo.edu
Subject: Vedio Housing
Organization: University of Waterloo
Distribution: na
Date: Fri, 14 Aug 1992 23:33:00 GMT

Hi, everybody.
I recently purchased a SONY TR-51 vedio camera, and was trying to purchase
an underwater housing for it. I called Performence Mail Order and they
told me that they no longer sell vedio housing anymore. Does anybody
know a mail order place that I can buy a housing with a reasonable price?
Thanks in advance.



Victor Sun
From: FKK@SLACVM.SLAC.STANFORD.EDU
Newsgroups: rec.scuba
Subject: MID WEEK DIVE BUDDIES WANTED
Date: 14 Aug 92 00:32:13 GMT
Organization: Stanford Linear Accelerator Center

I an a PADI Divemaster, UW photographer, with a 12' inflatable boat,
(25HP motor, depth finder etc - the works) looking for people who can
take a day off during the week when conditions are good to go to
Monteray, Carmel or North Coast.  I also go on weekends but its much
more fun to go mid week when it is not as crowded.  If interested,
contact me through e-mail or call Frank King at 415-926-2296- days.
From: peterson@hpl.hp.com (Chris Peterson)
Newsgroups: rec.scuba
Subject: Re: Dry suit repair question
Date: 12 Aug 92 16:47:46 GMT
Organization: Hewlett-Packard Laboratories, Palo Alto, California

In article <IeWGGNO00WBMM1N9AX@andrew.cmu.edu> ps3p+@andrew.cmu.edu (Peter A. Simon) writes:
>I have a back entry, 1/4" neoprene dry suit made by Fitzwright
>(Canadian).  The zipper needs to be replaced.  Can anybody recommend (or
>even just name) an outfit who does this kind of work?
>
>Thanks a lot!
>
>
>-peter

I have been pleased with the repairs performed on my Viking dry suit by
SeaMe in San Diego, California USA.  Monterey Bay Wetsuits, in Monterey,
California, would also be a good prospect; they make no-nonsense wet suits
and neoprene dry suits, and have a pretty good repuation locally.


	     SeaMe (ask for Karen) 
	     4352 Poplar Street
	     San Diego, CA 92105 USA
	     619/563-9033

	     Monterey Bay Wetsuits (Tom & Beryl)
	     207 Hoffman Avenue
	     Monterey, CA 95940 USA
	     408/375-7848

Ask for a "pressure test" from whomever you choose to do your repairs.
It's an inexpensive way to check for small leaks before they become big leaks.

P.S. Sit down; take a deep breath.  Replacing a zipper will be the single,
most expensive dry suit repair.  Expect to be charged $200-$300.
-- 
Chris Peterson                                     Hewlett-Packard Laboratories
                                                    Research Computing Services
                                                              Palo Alto, CA USA 
(415) 857-6432                                              peterson@hpl.hp.com
From: story@sgi.com (David (Duis) Story)
Newsgroups: rec.scuba
Subject: Sport Divers' Inability to Calc Repetitive Dives
Date: 14 Aug 92 22:07:33 GMT
Reply-To: story@sgi.com
Organization: Silicon Graphics, Inc.

Here's some cheerful food for thought.  This comes from the abstracts
of the 1992 UHMS Annual Scientific Meeting.  (Anyone have the
proceedings yet?)

Title: "The Average Sport Divers' Inability to Calculate Repetitive
	Dives"

(E. Schinazi, Hermann Center for Hyperbaric Medicine, TX, USA)

'Proper calculation of repetitive dives using standard dive tables is
a skill required for certification as a basic Open Water scuba diver.
Previous surveys have suggested that many divers lose this ability
after completion of their course.  A survey was designed to test the
ability of trained divers to calculate residual nitrogen and
repetitive dive designation groups utilizing examples similar to those
taught during scuba training.  Subjects were allowed to use any dive
table configuration taught in training.  Of those approached during a
national meeting, only 10% (284 divers) agreed to participate in this
survey.  Surveyed divers ranged in certification from basic open water
to instructor level and from 1 month to 20 years experience.

 OVERALL, 65% (186) HAD DIFFICULTY IN DETERMINING THE REPETITIVE GROUP
AND RESIDUAL NITROGEN TIMES FOR A STRAIGHTFORWARD MULTIPLE DIVE
PROFILE.  A score of 100% was considered "passing", which is
equivalent to certification requirements.  Subjects with one to three
years experience accounted for the highest nuber of incorrect surveys.
Those with more experience performed slightly better.  Interestingly,
23 OF THE 72 INSTRUCTORS WHO TOOK THE SURVEY WERE UNABLE TO COMPLETE IT.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 Since participation was voluntary, it may be assumed [that]
individuals who agreed to be tested were more likely to do well than
those who refused, and the results were skewed to the positive.  WE
CONCLUDE THAT MORE THAN HALF OF CERTIFIED DIVERS ARE UNABLE TO UTILIZE
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DIVE TABLES CORRECTLY.  This has great implications for diving safety
^^^^^^^^^^^^^^^^^^^^^
of which training agencies and dive tour groups should be aware.'

		[Emphases, paragraph breaks, and typos are mine.]


Food for thought.  Was YOUR instructor one of 23/72 (32%!!!) who
couldn't complete that survey?  Are YOU one of the 65% who can't do a
repetitive dive calculation?

Cheers,

Dave Story                        NAUI AI Z9588, PADI DM 43922, EMT
story@bent.esd.sgi.com		   Oxygen is a drug in California.
Newsgroups: rec.scuba
From: adb@herboid.uucp (Anthony DeBoer)
Subject: Re: Thermodynamic Decompression
Organization: Linda's Dragon Memorial Society
Date: Thu, 13 Aug 1992 03:26:32 GMT

Bill Mayne <mayne@ds1.scri.fsu.edu> writes:
>Incidentally I have also encountered an interesting problem using
>my Aladin computer as a depth and time recorder on nitrox dives
>taking advantage of the nitrox to shorten decompression. (I consider
>every dive a decompression dive since at least a safety stop is
>included. Mostly I've used nitrox or O2 only for extra safety,
>sticking to air schdules. But under the guidance of experienced
>divers and instructors I'm getting less conservative.) The problem
>with the Aladin is this: Once the computer thinks I'm bent it won't
>work normally for 24 hours. I can't reset the max depth or dive time for
>another dive or recall logged dives. I need a "There, there!" button to
>tell it I'm okay and to forget about my N_2 status and just record dives.
>...
>I'm happy to say I'm unbent, though.

Couldn't you just do extra "safety" decompression up to the minimum amount
of decompression the computer wants?  I find that even if I know I could
get out of the water sooner, I have no trouble hanging on the line a bit
longer, especially if it's reducing the already-remote possibility of a
chamber trip.  From what I understood, the best safety factor comes from
doing nitrox decompression on air tables/computers, especially as it
lets you stick to the limits (ie. no extra safety factors or "stepping
back" on the tables) without feeling guilty.
-- 
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: 160955r@garnet.berkeley.edu ()
Newsgroups: rec.scuba
Subject: Hawaii info request
Date: 18 Aug 1992 05:18:43 GMT
Organization: University of California, Berkeley
NNTP-Posting-Host: garnet.berkeley.edu

I'll be in Hawaii (Maui) in a week or so and I wonder if any
of you people out there have some info regarding best scuba
locations on that island. 

Thanks!


-- 
Radu T. Tomescu at UCBerkeley
Department of Economics

Newsgroups: rec.scuba
From: mstacc@ultb.isc.rit.edu (M.S. Tremblay)
Subject: Info needed about NC - Cape Hatteras
Originator: mstacc@ultb
Reply-To: mstacc@ultb.rit.edu ()
Organization: Rochester Institute of Technology
Date: Wed, 12 Aug 1992 21:47:45 GMT

Was wondering if anyone has info, good or bad, about dive operators in
the Cape Hatteras area.  We have info on one, their name is 'Discovery
Diving Co', in Beaufort, NC.  We are trying to get a trip arranged for the
fall and want to check around for availability and price.  We need info
on lodging and diving.

Please e-mail and I'll post if there is interest in the results....
-- 
-Mark Tremblay              
  software specialist                       Internet:    mstacc@ultb.isc.rit.edu
     Rochester Institute of Technology      Phone:       716.475.2986
Newsgroups: rec.scuba
From: trumpet-user@dkfz-heidelberg.de (Don Ward)
Subject: Re: periodic re-certification (was: anyone heard of PDSI?)
Organization: German Cancer Center
Date: Fri, 14 Aug 1992 06:55:50 GMT

In article <1992Aug13.031825.20826@herboid.uucp> adb@herboid.uucp (Anthony DeBoer) writes:

>Dave Waller <dave@hpdstma.ptp.hp.com> writes:
>>... do you support the periodic re-evaluation of private pilots to
>>operate small aircraft, or do you view this in the same light that you do
>>the prospect of re-establishing scuba certification?

>If an individual's actions could only harm that individual, then letting
>them do whatever they felt with no certification or anything would be
>perfectly alright.  However, that's not always the case.  Dave's analogy
>of pilot's certification should bring this to light, as IMHO the
>requirements there are not so much for the pilot's own benefit as for the
>safety of his/her potential passengers and the people he/she flies over. 
>An aircraft augering in through the roof of my house could violate
>something a bit more essential than just my civil liberties.

>The case of scuba divers is not quite so extreme, but the same argument
>applies for the safety of one's buddy.  This is why the NAUI bottom line
>is not "Is this guy going to go out and get himself killed?" but rather
>"Would I trust this person to go diving with one of my loved ones?".
>Buddies depend on each other, and even if you become more capable of
>taking care of yourself as you gain experience, you do more ambitious
>dives too.  When an instructor signs somebody's card, they're not just
>letting that person dive, they're also telling other divers that this
>person is safe to go diving with and is a buddy they can turn to in an
>emergency.  Or at least that's the way it should be.

I am beging to wonder if enverimental awareness is being forgoten in this
discussion. Here in Germany, many very good dive sites are closed to diving
because too many divers didn't follow good diving practice, i.e. walking on
the bottom, distroying banks with their equp. etc. Too many divers have also
disrupted the feeding, breeding of fish causing a reduction in numbers. In
the Mediterranean, lots of good dive sites have been runied by divers that
were not aware of, not willing to follow good diving practice. Now the 
govt's of different countrys are steping in to control this. They don't get
so upset when a diver kills himself or his buddy, but they do get upset when
divers distroy the envirment. Maybe if you divers in America start watching
eachother now, the govt. won't start watching you later.

don ward.

PS. Here in Germany the govt. even trys to tell us what equpment we can use
when we dive.
-----------------------------------------------------------------------------
if you want me to be able to read you post, then you have to set the
distrubution to world. I am in Germany. Thats why I have trouble with
my spelling. please excuse.
Don Ward at: zdv620@support.inet.dkfz-heidelberg.de
From: larry@gator.rn.com (Larry Snyder)
Newsgroups: rec.scuba
Subject: Re: Dixie Divers in Ft. Pierce
Date: 19 Aug 92 10:56:09 GMT
Organization: The Gator Public Access Unix Site - 219-289-3745

ebd@fang.att.com (Elliot B Dierksen) writes:

>In article <Bt6Iyn.5n0@gator.rn.com> larry@gator.rn.com (Larry Snyder) writes:
>>Does anyone have any experiences with Dixie Divers
>>in Ft. Pierce, Florida?

>I don't know if this is the same people or not, but I have an AVOID
>recommendation in that area. The boat was "Neptune" or "Neptune's Revenge"
>and they were expensive and NOT HELPFUL in the extreme. I still want very
>much to dive the USS Rankin in that area, but I will endure the boat ride
>from West Palm rather than give these people any more of my money!!

I'm sorry to hear that.  When I called them yesterday (Tuesday)
they had mentioned that they currently didn't do any local diving
in St. Lucie County -- most of it was in Palm Beach and Martin
Counties.  When I asked about the Nazi subs off the coast of Ft. 
Pierce that I saw recently in a scuba video -- I was told that yes,
they are out there about  9-10 miles down 85 feet but the water isn't
nearly as clear as it is in Pompano -- and they currently didn't dive
the site.  I was told that a new boat would be available - and the
captain wanted to work out an agreement with Dixie -- but this was
still in the works.

Have you dived anywhere in Central Florida?


-- 
Larry Snyder                                    internet: larry@gator.rn.com
keeper of the Gator                                  uucp: uunet!gator!larry
Newsgroups: rec.scuba
From: rarobert@ursa9.cs.utah.edu (Robin Roberts)
Subject: Re: Boyancy control with drysuits
Date: 13 Aug 92 13:29:14 MDT
Organization: University of Utah CS Dept

>Do you use your BC for bouyancy or just the suit. Personally I use my
>suit (I use a membrane, apparently not so easy with a neoprene suit)
>for bouyancy. This means that I have to be correctly weighted close
>to neutral bouyancy without any air in suit. If too heavy then more
>air has to be put into the suit, which leads to the problems when rising
>since there is much more air to dump and suit dumps are never as fast
>as BC dumps at getting rid of air.

i do not recommend using a dry suit for buoyancy control... even if you
are also wearing a BC (i believe that you should always wear a BC with a
dry suit, anyway)...  
the BC is essential, for some of the reasons that are mentioned above, 
such as the fact that a BC can be vented much faster than a dry suit.  
IMHO, air in a dry suit is solely for the purpose of warmth and to 
prevent squeeze.  As someone else in a previous posting suggested, 
use the minimum amount of air in the suit that is necessary.  By using 
less air in the suit, body positioning becomes less of an issue.  
That is to say, it's still not a good idea to intentionally invert 
(bye bye fins!), but it's less likely that you'll accidentally invert.  
lots of extra air rolling around in your dry suit makes it very 
difficult to control your positioning, etc.

				rr.


Newsgroups: rec.scuba
From: bmacmill@epas.utoronto.ca (Bruce MacMillan)
Subject: Source of Supply of Used Dive Computers
Organization: University of Toronto - EPAS
Date: Sat, 15 Aug 1992 15:57:56 GMT

This is a general inquiry regarding a source of supply of used dive computers
of all types, models and makes.  I am interested in building up a small
collection of used dive computers.  Could anyone make any
recommendations in this regard?  I notice that there was some
discussion recently about used Delphi computers.  Can anyone give me
the address I could write to for more information on this matter?
Thank you all for your interest and assistance in these matters. Best wishes.

-- 
Bruce MacMillan
bmacmill@epas.utoronto.ca
Voice: (416) 599-9261	(519) 542-4572
FAX: (416) 978-8821	(519) 542-4854
Organization: Senior, Civil Engineering, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.scuba
Date: Fri, 14 Aug 1992 15:44:07 -0400 
From: "Peter A. Simon" <ps3p+@andrew.cmu.edu>
Subject: Eric Youngblood


Your mail bounces.  "No such host."
From: curlandm@prism.cs.orst.edu (Matt Curland)
Newsgroups: rec.scuba
Subject: Any opinions about the Dacor Omni computer?
Date: 22 Aug 92 12:46:49 GMT
Distribution: usa
Organization: Oregon State University, Computer Science Dept

Greetings!

I'm looking at purchasing one of these, and am mainly curious if
anyone has had any experiences, good or bad with them.

Thanks in advance,
Matt

Matt Curland. .  .   .    .      .          curlandm@prism.cs.orst.edu
______________________________________________________________________
Power always has to be kept in check; power exercised in secret,
especially under the cloak of national security, is doubly dangerous.
- William Proxmire
Newsgroups: rec.scuba
From: ebd@fang.att.com (Elliot B Dierksen)
Subject: Re: Dixie Divers in Ft. Pierce
Organization: AT&T Tax Systems Development, Maitland FL
Date: Tue, 18 Aug 1992 18:40:19 GMT

In article <Bt6Iyn.5n0@gator.rn.com> larry@gator.rn.com (Larry Snyder) writes:
>Does anyone have any experiences with Dixie Divers
>in Ft. Pierce, Florida?

I don't know if this is the same people or not, but I have an AVOID
recommendation in that area. The boat was "Neptune" or "Neptune's Revenge"
and they were expensive and NOT HELPFUL in the extreme. I still want very
much to dive the USS Rankin in that area, but I will endure the boat ride
from West Palm rather than give these people any more of my money!!

EBD
-- 
Elliot Dierksen   "Is that a real poncho... I mean is that a Mexican poncho or
                   is that a Sears  poncho?  Hmmm... no foolin'..." -- F. Zappa

W) e.dierksen@att.com  (407) 660-3377     H) elliot@alfred.UUCP  (407) 290-9744
Newsgroups: rec.scuba
From: tim@ais.org (Tim Tyler)
Subject: Article in Current _SCUBA Times_
Summary: Famed Diver Marty Snyderman is stupid!
Organization: UMCC
Date: Thu, 20 Aug 1992 23:46:06 GMT

                                           Friday, 14 August 1992
Letters to the Editor,
Scuba Times
14110 Perdido Key Drive, Suite 16
Pensacola  FL
32507

     I just finished reading Marty Snyderman's article entitled A
Song In The Night in the September/October issue Scuba Times.  I'm
not one to follow the careers of divers other than my own dive
buddies and of course myself, but certainly as someone who has been
a certified diver since 1978, it is difficult to not have heard of
or seen the work of Mr. Snyderman, & thus have a great respect for
him as an accomplished diver.

     Unfortunately, while I might continue to respect his
underwater cinematography, I no-longer have much respect for Marty
Snyderman as a diver.

     While 60% of A Song In The Night is focused on the Great
Barrier Reef dives with the film crew, Marty then talks about his
rather spur-of-the-moment (sure, why bother with a dive plan?!)
night dive --the experiences during which provide the title to his
article-- and all of a sudden, he stops using the pronoun 'we,' &
replaces it with 'I.'

     As I read on, keeping in mind that Marty had already stated
that the currents were "hellacious," that there were known to be
sharks in the area, that the water was cold, & that he was going
down to a wreck below 50 feet, I assumed he was merely focussing on
his own experience that night, & not that of his dive-buddy.  

     Then I stared in disbelief at the line "I was pretty sure I
was the only person in the water that night for miles. I liked that
thought."

     I think the article is a clear demonstration that stupidity
(not to mention irresponsibility, for daring to condone the solo
night/cold-water/wreck/current dive in Scuba Today) isn't just a
sign of novice divers.  Marty's article shows that it can be a
symptom of anyone, regardless of dive equipment, qualifications, or
experience. I guess for that, I am thankful to him and Scuba Today.

     Even if I'm making my 5000th dive in some quarry in Ohio,
common sense will still be a part of my dive plan.



                                                       Sincerely,


                                                        Tim Tyler


-- 
 Tim Tyler   Internet: tim@ais.org  MCI Mail: 442-5735  C$erve: 72571,1005
P.O. Box 443     Packet: KA8VIR @KA8UNZ.#SEMI.MI.USA.NA
Ypsilanti MI
48197-0443                  PADI, USPA, AFCEA, INEOA, P226, VFR700, etc.
Newsgroups: rec.scuba
From: dave@hpdstma.ptp.hp.com (Dave Waller)
Subject: Re: VIP/HYDRO & air fills?
Organization: Hewlett Packard
Date: Wed, 19 Aug 1992 16:54:06 GMT

In article <1992Aug18.183435.1@sscvx1.ssc.gov>, schludermann@sscvx1.ssc.gov writes:

(About an airfill station that refuses to fill a hydro'd tank without a
visual sticker)

If possible, get your fills somewhere else. This sounds to me like a bit
of money grubbing. Several of the shops in my area, and the one I work with the
most, will fill a tank that is within one year of a hydro.

Part of the process of hydrostatic testing involves a visual inspection first.
This MUST be done to ensure that there are not any gross structural
compromises that might make the tank crack during the testing process. While
the test is done under the safest conditions (this is the primary reason
why a hydraulic rather than a pneumatic test is performed), there is still
risk from a severely weakened tank while being pressurized hydraulically.

-- 
Dave Waller
Hewlett-Packard Co.
Workstation Systems Division
Sunnyvale VAB Consulting
(408) 746-5324
Newsgroups: rec.scuba
Subject: Tubas?  Scuba!
From: ttasset@vax1.umkc.edu
Date: Thu, 20 Aug 1992 02:01:03 GMT
Organization: University of Missouri - Kansas City

I was looking for a newsgroup that had to do with anything about tubas, but
since this is the closest sounding one, I thought that I would just say...

	"TOOT TOOT!"

	-"Tuba" Tom