Does anyone use DCIEM dive tables?
Jeremy Arthur Hamming
Spud Diver
I do use them, and I like them a lot. I usually teach them in my Advanced
and/or Altitude courses. They have a lot of advantages over the
Navy/Modified Navy tables, and a great deal of advantages over the "Wheel"
Later...
Robert Barkley -- NAUI Instructor
Spud...@AOL.COM
Jason Rogers
Jason =;
Charlie Hammond
I am PADI trained and have both the Table and Wheel version of the
PADI/DSAT RDP. Generally, that is what I use. But I also have the DCIEM
table, and for cold water and/or strenuous conditions, I at least look at it.
DCIEM developed its table under cold water conditions with the result, among
others, that it is considerably more conservative than the RDP. It is also
more conservative than the NAUI tables and, persumably, any other tables
based on the US Navy tables.
On the other hand, the DCIEM table is arguably unnecessarily conservative for
tropic conditions. You'd be giving up a good bit of bottom time that is problaby
pretty safe.
The negative thing about the DCIEM tables is that it requires you to do
multiplication using a "repeat factor" (I think that's what it's called)
rather than adding a "retained nitrogen" time, like the RDP, NAUI and most
other tables. So the math for repeat dives using DCIEM is a bit more
complex, especially for three or more dives in a single day.
..And since my wife and I got our Matrix computers on Saturday, we'll probably
be spending less time in any tables!
BTW -- the comparison in another reply to this string between the Wheel and
DCIEM confuses me. The wheel is based on the same data as the table version
of the RDP. It gives exactly the same results if you stick to 10 foot depth
intervals. (i.e. don't use the 5 foot increments on the Wheel.) So either
the table RDP or the Wheel should compare equally to the DCIEM tables.
The Wheel, on the other hand, clearly excells on multi-level dive computations.
--
Charlie Hammond -- Digital Equipment Corporation -- Nashua NH USA
All opinions expressed are my own and do not necessarily reflect
my employer's position.
Mike Zimmerman
Charlie Hammond <ham...@star.enet.dec.com> wrote:
>On the other hand, the DCIEM table is arguably unnecessarily conservative for
>tropic conditions. You'd be giving up a good bit of bottom time that is problaby
>pretty safe.
Well I might get jumped on for this, but gee why not :-)
I've done 2 Blackbeards trips now, both using a Solution dive
computer, and a set of DCIEM sport tables. On the last
trip I did 18 dives over 5 days, max depth, hmm 108fsw, min
depth was around 15fsw, even a 60min @60fsw tossed into the middle.
I was into deco a lot (according to the tables). I was rarely
even close on my Solution. But I said to myself, ya know I'm
on a liveaboard doing multiple multi-level dives over multiple days,
I'm doing some major safety stops, even if my computer doesn't think
I need to. I usually did (at least) 5@20 and 5-10@10. These "safety
stops" ended up letting me clear the tables all but once that week.
Now of course I don't consider stops wasted time. I was still
in the water (and that's always better than being dry, right?)
just hanging around, watching the bottom from a really "macro"
view. Saw some of my best morays and turtles that way.
Now I realize that I am _almost_ advocating deco diving here
(hellfire and brimstone to follow :-) ) to someone who is not
diving a computer (and is relying solely on the tables). Do keep
in mind that
a) DCIEM tables ARE designed for multi-level diving (I scored
my dives as square, would have perhaps done them multi-level
had I been totally relying on the tables) and could be used
that way.
b) different tables are designed for different kinds of diving.
I'd wager a burger/beer that the DCIEM tables might be less
restricting than the USN tables for a week of "repetitive warm
water vacation diving". I'd wager the same burger/beer that
the PADI tables/Wheel would be the most, hrmmm, "friendly", though
frankly for a week of diving, *I* prefer a more "stern" set of
tables.
c) the DCIEM tables are based on a different algorithm than the
USN and PADI tables (which share a great deal of commonality
in their underlying algorithm).
>The negative thing about the DCIEM tables is that it requires you to do
>multiplication using a "repeat factor" (I think that's what it's called)
Agreed, but if you are logging your dives, you've got a half square
inch somewhere where you can scratch the math out...(I do it on the
back of the previous dives' log sheet.) There is always the
chance for error, but frankly the numbers begin to follow a pattern
almost after a while, so you'd have a sense of when you screwed up.
So me, I use the tables, and take their built in conservatism
as a hedge against all the other crazy stuff I do :-)
Mike
--
Mike Zimmerman < zim...@aur.alcatel.com > Alcatel Network Sytems, Ral, NC
*My opinions, not Alcatel's* [\] NC Diving: http://www.vnet.com/scuba/
A is A. Man who say it cannot be done should not interrupt man doing it.
John Plocher
: ... using a Solution dive computer, and a set of DCIEM sport tables.
And I thought I was the only one doing the "computer with tables as
backup" thing :-) It is a very useful thing, knowing how you sit
table-wise as you go thru a week+ of diving. Just using a computer, I
find it hard to tell when I am completely saturated - relating total
desat times and NDLs in the dive planner mode just isn't as obvious as
ending up on the tables as an X, Y, or Z diver!
(It also helps if your computer fails - treat the aborted dive as a
square profile at your max depth and carry on from there on the
tables. Of course, if you haven't been logging your dives as you go,
you have no idea how you stand nitrogen-wise, so you must wait the
standard 24 hours to insure you are clear before diving on a new
computer or tables)
The big gotcha, though, is that many tables say I'm clear after 6
hours. My computers all can "give" me more that a 24 hour clear time.
So, on the computer it is a rep dive, while on the tables it is a fresh
set.
In my opinion, the standard sport diver tables are geared towards the
weekend diver - 2 to 6 dives over a 2 day period. For a week of
live-aboard diving with 4-5 dives per day, they tend to give shorter
surface intervals (with associated smaller nitrogen time carryovers)
than I'd prefer. But, since I am not an expert on decompression theory
and the mathamatics behind it, this can only be one man's opinion :-)
--
John Plocher | PADI | plo...@scuba.net | An online resource for the
Scuba.Net | DM/AI | http://www.scuba.net/ | Monterey Bay Diving Community
Carl Heinzl
Mike,
I'm not going to jump on you - I'd never harass someone that I
respect, well, not much anyway, BUT, one of us is going to get a
couple burgers/beers out of it :^)
>b) different tables are designed for different kinds of diving.
> I'd wager a burger/beer that the DCIEM tables might be less
> restricting than the USN tables for a week of "repetitive warm
> water vacation diving". I'd wager the same burger/beer that
> the PADI tables/Wheel would be the most, hrmmm, "friendly", though
> frankly for a week of diving, *I* prefer a more "stern" set of
> tables.
I'll take this bet. I think that DCIEM are more restricting than USN
- you DID say USN (i.e. NOT NAUI, which is slightly more
conservative/restrictive). If you care to send me your profiles, I'll
do them all on the navy and PADI tables. I also will take you up on
the double or nothing on the PADI front. The reason being here is
that you probably blew the PADI tables out of the water on some of
your "individual" dives, so, from that prospect - when you hit
"emergency decompression" mode you have to stay out of the water at
least 6 hours (if you break the NDL by less than 5 minutes) or 24
hours (if you break it by more than 5 minutes). Sounds like I just
*might* get a copule of lunches, eh :^)
>c) the DCIEM tables are based on a different algorithm than the
> USN and PADI tables (which share a great deal of commonality
> in their underlying algorithm).
Yes, there is commonality, but the controlling compartment in the NAUI
table is the 120 min compartment, PADI uses 60 minutes, so you're
essentially clear in 6 hours.
So, when do I get my burgers??? :^)
-Carl-
Mike Zimmerman
Carl Heinzl <c...@zurich.ai.mit.edu> wrote:
>
>Mike,
>
>I'm not going to jump on you - I'd never harass someone that I
>respect, well, not much anyway, BUT, one of us is going to get a
>couple burgers/beers out of it :^)
>
>>b) different tables are designed for different kinds of diving.
>> I'd wager a burger/beer that the DCIEM tables might be less
>> restricting than the USN tables for a week of "repetitive warm
>> water vacation diving". I'd wager the same burger/beer that
>> the PADI tables/Wheel would be the most, hrmmm, "friendly", though
>> frankly for a week of diving, *I* prefer a more "stern" set of
>> tables.
>
>I'll take this bet. I think that DCIEM are more restricting than USN
>- you DID say USN (i.e. NOT NAUI, which is slightly more
>conservative/restrictive).
Keep in mind the DCIEM are multi-level capable :-) Not sure
though if I'll need this "feature" to save my burger(s). Of course
if I didn't sketch out my dives (from the data in my Solution) then
I may be in trouble :-)
>If you care to send me your profiles,
I'll pass 'em along
>I'll do them all on the navy and PADI tables.
I'll do the same. I have a copy of all 3 tables on slates which
I carry with me all the time (held together by a keychain ring).
Really handy for whipping out if your dive profile changes
unexpectedly (shorter or longer) and even your "alternate"
profiles don't muster up.
> I also will take you up on
>the double or nothing on the PADI front. The reason being here is
>that you probably blew the PADI tables out of the water on some of
>your "individual" dives, so, from that prospect - when you hit
>"emergency decompression" mode you have to stay out of the water at
>least 6 hours
Oooh, now you're really being greedy, calling in the "fine print". :-)
>Yes, there is commonality, but the controlling compartment in the NAUI
>table is the 120 min compartment, PADI uses 60 minutes, so you're
>essentially clear in 6 hours.
True. The DCIEM tables don't clear you for 18 hours, so the
whole week becomes almost one long "dive day" of repetitive dives.
>So, when do I get my burgers??? :^)
Hmm, I'll be in Boston around Xmas-time...of course I'm
still not sure who is buying :-)
Mike Zimmerman
John Plocher <plo...@Sun.COM> wrote:
>Mike Zimmerman (zim...@aursaf.aur.alcatel.com) wrote:
>: ... using a Solution dive computer, and a set of DCIEM sport tables.
>
>And I thought I was the only one doing the "computer with tables as
>backup" thing :-)
Nope, two of us crazy people out here...
>(It also helps if your computer fails - treat the aborted dive as a
>square profile at your max depth and carry on from there on the
>tables. Of course, if you haven't been logging your dives as you go,
>you have no idea how you stand nitrogen-wise, so you must wait the
>standard 24 hours to insure you are clear before diving on a new
>computer or tables)
Yup. Just like the Energizer Bunny, if your computer
fails (and you have been backing up your dives on tables)
you can "keep on going". I find this extra step much less
"tedious" than piddling away a day on deck (staring at a
dead computer) while my friends are diving.
>In my opinion, the standard sport diver tables are geared towards the
>weekend diver - 2 to 6 dives over a 2 day period. For a week of
>live-aboard diving with 4-5 dives per day, they tend to give shorter
>surface intervals (with associated smaller nitrogen time carryovers)
>than I'd prefer. But, since I am not an expert on decompression theory
>and the mathamatics behind it, this can only be one man's opinion :-)
I'd agree. You hear people talk about the "Wednesday bends"
(ie. middle/late part of a week-long liveaboard trip). Some
people will actually sit out a day mid/late week to "correct"
for what some would perceive as a deficiency (or perhaps a
one might call it a mis-application) of the tables (ie. were they
really designed with multiple dives over multiple days
in mind?). Me, I just do the mongo safety stops. All week,
starting at dive one.
Regards,
Mike Zimmerman
>>b) different tables are designed for different kinds of diving.
>> I'd wager a burger/beer that the DCIEM tables might be less
>> restricting than the USN tables for a week of "repetitive warm
>> water vacation diving". I'd wager the same burger/beer that
>> the PADI tables/Wheel would be the most, hrmmm, "friendly", though
>> frankly for a week of diving, *I* prefer a more "stern" set of
>> tables.
>
>I'll take this bet. I think that DCIEM are more restricting than USN
>- you DID say USN (i.e. NOT NAUI, which is slightly more
I keep a set of SSI tables that claim to be USN as well as
having a more conservative set of "doppler" limits.
>conservative/restrictive). If you care to send me your profiles, I'll
>do them all on the navy and PADI tables. I also will take you up on
>the double or nothing on the PADI front. The reason being here is
>that you probably blew the PADI tables out of the water on some of
>your "individual" dives, so, from that prospect - when you hit
>"emergency decompression" mode you have to stay out of the water at
>least 6 hours (if you break the NDL by less than 5 minutes) or 24
>hours (if you break it by more than 5 minutes). Sounds like I just
>*might* get a copule of lunches, eh :^)
Well I'm posting this with a slight bit of trepidation...
[not about the burgers..that's a small price to pay
for good debate :-) ]
This is a summary of my dive profiles while spending a
week on Blackbeards back in July. During that week I
did 18 dives, few followed a square profile and I used
a Suunto Solution computer to track my nitrogen absorption.
After every dive I logged and marked it as though I had been
diving with the DCIEM sport tables. On many dive logs
I also "sketch" out my profile since the Solution will play
back your dive in 3 minute increments (showing deepest depth
during that interval). I did this for three reasons:
- in case my computer crapped out during the week I would not
have to sit out for 24 hours.
- I like using the tables as a backup as a "sanity check".
ie. if my tables say "no way no how, not even close" then
maybe my computer is wigging out but not yet dead.
- I figure a week of repetitive diving stresses any decompression
modelling algorithm. If I dive my computer (which is giving
me "credit" for all the time I am not at my deepest depth) and
then also try to stay within the tables (which are not giving me
that "credit") I'm padding my safety margin a good bit. I mean
the 100' dive listed below was a wall dive. If this had been
one dive day with no repetitive diving to be done, I'd have,
well, been more aggressive :-) But my goal for a weeklong
trip is to be able to make dives all week long, no chambers
for me thanks.
During the week I "blew" (exceeded) the DCIEM tables once. I
chose to mark this dive as one fsw more shallow than I had been.
This is a (perhaps) can of worms I don't want to pry open (yet).
Suffice it to say I'm willing to defend it as a PERSONAL choice,
not willing to recommend it. Do remember that most of the dives
were generally very multilevel in nature.
[ end of my disclaimer ]
Key:
'SI' is Surface Interval
'+' means dive required decompression according to the tables.
I NEVER entered mandatory decompression according to my computer.
'-' means tables are blown for this dive (exceeded limits and/or
missed required deco).
(!!) Planned and executed as a multi-level dive. Not able
to be done with USN tables, counted as "square" for them.
*** PADI does not technically have deco dives, so any blown
dive is considered deco for this article.
Max PADI USN (with
SI Depth Time DCIEM RDP deco) Note
--- ----- ---- ----- ----- ---------- ------
- 17 47 B I B
1:00 48 36 E Q G
20 5
5:15 17 41 B J C
2:30 18 50 B L C
10:16 91 23 -G+ -O G Ok on DCIEM and PADI tables
40 1 IF counted as 90fsw. Avg
20 2 depth(from computer playback of
10 5 dive was less than 80fsw.
(** see my note below)
5:50 48 32 E J G
20 5
10 5
2:30 56 39 F S K+
20 5
3:00 51 31 F O -K+ 30 min would have been ok. (**)
11:00 70 33 F+ P H
10 10
3:30 70 39 G+ -T? -L+ 4 min more deco rq'd by USN
20 5 Kills PADI limit by 5 minutes
10 5
1:40 55 35 G+ P -M+ 9 min more deco rq'd by USN
10 5
18:00 84 23 E+ O G
40 2
20 5
10 5
4:30 21 31 B H E
1:30 50 36 E L I
10 5
3:00 42 46 F Q J
10 5
12:00 100(!!) 12 I+ (as 26@100')
70 14 G+ P
20 5
10 10
3:30 58 42 G+ T K+
10 15
1:30 48 22 D M K
20 5
10 10
Dives blowing tables 1 2 3
Dives in deco 7 2*** 6
(?) As for the 2 PADI table violations, I've run them thru
a simulator (which I've ben writing for my own learning)
and confirmed that O is a fair group for the first violation
and the second ended up being a U. I'm not recommending
that people add these numbers to their tables, just saying
for for the sake of carrying the table comparison to the end
I used these groups.
So what the heck did I glibly bet a burger and a beer on anwyay? :-)
a) that the DCIEM tables would be more friendly than the
US Navy tables (for week-long diving)
b) that the PADI tables would be EVEN friendlier.
I think I'm ok on (a) :-) although technically I blew
the DCIEM tables before I blew the Navy tables, but
I blew the Navy tables more often, so.... of course I was
trying NOT to blow the DCIEM tables (they were my backup), and was
not paying any attention to the USN.
(%%)In this regard if anyone else cares to post (or email)
a list of their profiles from a trip, another comparison
might be interesting (ideally it would be someone who
only watched their computer and paid no attention to
tables)
As for (b) I might have been as willing to let the
first PADI "blow" slide by, but the second I would not felt
good about. That's looking like the time to invoke
the "you screwed up" penalty clause. Had I been diving PADI
as backup (instead of DCIEM) I would have ended that
dive earlier. Again I think (%%) more data would be
worth a look.
Bryan Douglas Crawford
thread. The DCIEM tables are unlike any other tables in that the NDC times
are based on emperical measurement of microbubble formation in real divers,
not on some mathematical model. This has some surprising results WRT
conservatism...the DCIEM tables are more *liberal* than the PADI RDP at
shallow depths, but more conservative deeper. However, I found that when
I switched to the DCIEM tables I got longer dives, due to the multi-level
capabilities.
Finally, I posted (intended to mail it, but I hit the wrong key) something
a while back saying that I'd scan my copy of the DCIEM table and send it to
someone who was curious, because I was sure they'd want a legal plastic copy
for their BC pocket anyway. However, I recieved a nice email from Gain Wong
asking me not to break their copyright, and informing me that there are lots
of places where the tables have been published for anyone to have a look at
if they're interested. So as a public service, here is a listing of all the
publications which include copies of the DCIEM tables if you're interested:
> the NAUI Sport Diver Manual, the NASDS Safe Scuba (entry-level) Manual,
> the DCIEM Diving Manual (published by U.D.T. and distributed by our
> affiliate, Bonica Precision Canada, located in Richmond, B.C.), Deeper
> Into Diving by John Lippman (published by JL Publications in Carnegie,
> Australia), Diving Medicine for Scuba Divers by Carl Edmonds, M.D., Bart
> McKenzie, M.D., and Robert Thomas, M.D. (also published by JL
> Publications), Antarctic Scientific Diving Manual edited by Jeff Bozanic
> and published by the Research Support Division of the Antarctic Support
> Associates. The DCIEM tables will also appear in the next printing of
> the Jeppesen Sport Diving Manuals published by Mosby Lifeline, a Times
> Warner division.
Cheers
--
Bryan Crawford bry...@sfu.ca
Institute of Molecular Biology and Biochemistry
Simon Fraser University
Burnaby BC
Doug Taylor
<zim...@aursaf.aur.alcatel.com> writes
[snip]
>I'd agree. You hear people talk about the "Wednesday bends"
>(ie. middle/late part of a week-long liveaboard trip). Some
>people will actually sit out a day mid/late week to "correct"
>for what some would perceive as a deficiency (or perhaps a
>one might call it a mis-application) of the tables (ie. were they
>really designed with multiple dives over multiple days
>in mind?). Me, I just do the mongo safety stops. All week,
>starting at dive one.
>
>Regards,
>Mike
>
Hi Mike - I'm also one of the 'crazies'. As my Aladdin Pro is based on a
similar model to my tables, it makes sense to have tables as back-up and
also to be aware of limits in the tables that my PDC doesn't mention !
Diving on Buhlmann tables, there's a recommendation that you take a
day's break every 7 days of continuous diving as well as a warning not
to do more than 3 (yes, 3) dives in any 24 hour period.
The main reason as I understand it (if anyone knows better, please
correct me) is that the tissue compartments used in the calculations
*may* not include the very, very slowest tissues. There is therefore a
possibility that these ultra-slow tissues can build up N2, given a long
accumulated period underwater. Without sufficiently long surface
intervals (they off-gas very slowly by definition), they could become
the controlling tissues without the tables or the PDC being 'aware' of
it.
Now this is just speculation, but I'd have thought that for these v.slow
tissues, stops are no more useful than spending the same time on the
surface - but as you say, you don't see so much!
Best regards,
Safe diving,
Doug Taylor
Sub-Aqua Association UK, National Instructor #146
'The Friendliest Divers in the World'
Turnpike evaluation. For information, see http://www.turnpike.com/
Charlie Hammond
In article <44hgof$3...@morgoth.sfu.ca>,
bry...@news.sfu.ca (Bryan Douglas Crawford) writes:
> ... The DCIEM tables are unlike any other tables in that the NDC times
>are based on emperical measurement of microbubble formation in real divers,
>not on some mathematical model. ...
This statement conflicts with my understanding. I think that you will find
that both the DCIEM and the PADI/DSAT RDP tables have been adjusted based on
studies with real divers. But I think that both are also based on mathematical
models.
The RDP is based on a pretty much standard Haldane-type model, with it's own
set of parameters. The Haldane model has all compartments directly exposed to
ambient pressure, which simulates the perfusion of essentially fully saturated
blood.
The DCIEM table is based on a model with four compartments. In order to simulate
difussion through tissues, only the first of these is exposed to ambient
pressure. The second is exposed to the first and third; the third to the second
and fourth. Like the Haldane model, the DCIEM model can be altered by changing
its driving parameters.
(If the Haldane model is called "parallel", then the DCIEM model must be
called "serial".)
At first glance, it may seem surprising that these very different models (and
some others too!) return results that are really quite similar. But then I
realizes why: Any model that returned results which were clearly outside the
realm of what experience shows to be safe, but not overly conservater, would be
quickly rejected and forgotten!
More info on the DCIEM (and other) tables can be found in:
Deeper Into Diving (which was mentioned in the original
John Lipmann posting.)
ISBM 0-9590306-3-8
L J Publications
P.O. Box 381
Carnegie, Victoria, Australia
US$39.95 + shipping from
Aqua Quest Publishing -- 800-93308989
I believe that the primary reason for the differences between the RDP and the
DCIEM tables is that is that the DCIEM table assumes cold water and a greater
level of work from the diver. PADI/DSAT set out to give the recreational diver
more safe dive time; DCIEM aimed at a different situation.
J Shepherd
Hey! What about using tables, with a computer as back up?
You work out if I'm joking.
Jason