From: phil@dynamed.dynamedia.COM (Phil Menzies)
Newsgroups: rec.scuba
Subject: Another happy Delphi User  (was: Delphi->Phoenix)
Date: Thu, 20 Aug 92 16:01:18 PST
Organization: DynaMedia
Reply-To: phil@dynamedia.COM
Distribution: world
X-Mailer: uAccess LITE - Macintosh Release: 1.6v1

I feel I must add my two cents worth to the postive stories from
Dave Duis and Dave Waller after having seen several negative
reports about Orca computers recently. 

story@sgi.com (David (Duis) Story) writes:

> I was at 170fsw, unusually well narced, when the computer began
> flashing at me.  I noticed the light and picked up the computer to
> figure out what it was saying.  Now realize that I've got 200+ dives
> with my Delphi, both no- and decompression diving, and have seen
> almost every mode (except ERROR, thank goodness!) that it has in it,
> AND I'm a computer geek to boot. 

davew@hp-ptp.ptp.hp.com (Dave Waller) writes:

> Yes, I seem to have lucked out on the unit that I have as well. It's a
> Pro, that's been on well over 150 dives at this point, many of them deep
> (the deepest was to *****CENSORED*****, and believe me, having those big
> digits and easy to read display makes a big difference when you're
> *_HEAVILY_* narc'd).
> At this point, the air-integration feature saved my butt: the Delphi
> decided that I did not have enough air left to complete my
> decompression stops.  When this happens the Delphi display switches
> between the usual numbers and the words "GO UP".  That simple message
> finally penetrated my narcosis haze, and I began moving up.  As I rose
> the narcosis lessened and I finally figured out what was going on.


I have used Orca computers for about 5 years now, and currently own
a SkinnyDipper II (actually branded as a Sherwood Sigma II), a Delphi
and a Delphi Pro.  Between them I have close to 300 dives on them.
The only two problems I have experienced were flooding of the original
Skinnydipper (the predecessor to the Skinnydipper II), which Orca
replaced free with the II which has a redesigned battery door, and
loose battery contacts in the Delphi (easily user-fixable by putting a
pressure-applying device such as foam rubber or a rubber band against
the battery clip.)  And about 6 months I helped a friend buy one of
the Orca "surplus" Delphi Pros and took it out a few times to "break
it in".

My personal experience is that these are reliable dive computers, 
although from some recent negative rec.scuba stories, it sounds like
there have been some marginal or defective units shipped as well.

I was initially resistant to the "air-integrated" designs.  But,
like Dave Waller, I have come to like the "remaining air time"
calculation as a quick cross check of progress on a dive.  What
may not be evident to people who haven't seen the Delphi (or Pro)
is that it also has a bar graph of tank pressure as well as a 
large digital readout of tank pressure.  So, you can use it the
same way as you would use a normal pressure gauge.  However, what
I find myself doing is frequent glances at both bottom time
remaining and air time remaining, supplementing the less frequent
monitoring of actual bottom time and actual tank pressure.  Between
the two forms of information, I find I have a (relatively) clear
picture in my mind (even when at those *****CENSORED***** depths
where the mind starts to turn to mush) of what is going on.

Besides the air integration, I really appreciate three key features
of the Delphi (and Pro):  A bar graph of the limiting N2 compartment
(so I can quickly visualize how much margin I have left on my
bottom time limits),  An ascent rate guidance bar, so that I can
pace my ascent rate to the computer, Simple alarm status messages
(such as the GO UP/GO DN messages mentioned by Dave.)  Having been
in narcosis, near-hypothermia and other disorientation situations,
I can't emphasize enough how important it is to have a computer
that presents the critical information in a LARGE, CLEAR,
UNDERSTANDABLE format.  So, stay away from computers that:
scroll information while underwater, are cluttered, don't present
critical information in analog (graphical) form as well as numeric,
and have small digits.

Last, but not least, there is the subject of redundancy and failure
modes.  Many people ask me what happens with an air-integrated
computer if it fails - wouldn't a mechanical depth gauge be better?
I dive with my SkinnyDipper II clipped to the hose of my Delphi Pro,
and take the extra Delphi along on dive travel trips as a ("on-the-
boat backup").  Having two computers underwater on each dive is 
valuable for two reasons: if one fails, you haven't blown a day
waiting to get back to a state where you can start to dive again 
with another computer or on tables; and one serves to cross check
the other, in case of a depth sensor or other malfunction.  I find
that the Skinnydipper always tracks within 0-3 feet of the Delphi Pro.
If the Delphi Pro were to fail (and I had no air indication or one
that was erratic), it hasn't changed the actual amount of air
remaining in my tank, and I would simply proceed immediately to the
surface at a safe rate (as indicated by the SkinnyDipper) including
any needed stops.  For my next dive, I would just switch to the
spare Delphi (or a loaner mechanical tank pressure gauge), and
continue diving for the rest of the week, using the SkinnyDipper
as the reference for bottom time limits and the Delphi just for
tank pressure monitoring.

So, not only am I happy with the funtionality and display of the
Delphi, but I have a robust dive monitoring system for a relatively
inexpensive price.  (And I can always upgrade to a Phoenix if one
of the Delphis fails.)

This has been a rather long article, but I hope it helps some of
you consider the factors in evaluating dive computer and gauge
setups.  (And, I have no relationship with Orca, EIT, or any dive
shop - I'm just a happy Orca user.)

Good Diving,
Phil

-------------------------------------------
Phil Menzies  -  DynaMedia, Alameda CA
Internet:        phil@dynamedia.COM