Norman

>Glad you are getting some diving in.

As always, when the weather allows - though I understand its not been too
good in your part of the world at the moment.  I hope it improves.

> This month I have abstained from
>diving due to my daughters wedding which was on sat. 17th June.(great day
>very happy man)

Congratulations, if only I could be so lucky with my two.

<big snip>
>David you appear to be on a quest to reduce your deco. even further.

My only quest as you call it is to do sufficient deco and no more or no less.
I do not wish to spend unnecessary time on deco, with the concomitant
equipment loading required to sustain it.

>I ran your dive profile on proplanner then on GAP default GF L .2 GF H .7
>then Gap no conservatism. You can see Gap and Proplanner are similar with
Gap giving a >few more
>minutes on its default setting.

What you are demonstrating here is the flexibility of a GF-based program over
a "conservatism" based program.  With the former, you have some control over
the profile and this is a meaningful control.  With the latter this is not
possible, and the controlling parameter dubious.

However, both of these profiles give 30 minutes more deco than I did, and as
I mentioned in a private email to someone, the debate here is not just tables
vs. computers, its also about deco profiles in general.

>GAP with no conservatism is the closest to
>your profile.

This is incorrect.  What you have shown is that GAP with no conservatism
produces a similar in water time than me.  My deco profile was in fact
considerably different to that you put forward.  E.g. my first stop was 33m,
your GAP example is 18m.

>(I ran your friends profile'VR3' on the computer and it was
>spot on, he followed his plan)

I would expect this to be the case and he is a very competent and experienced
diver.

>Basically it is back to opinions, there are enough programmes out there it
>is up to you. The reasons why you choose one and not the other is based on
>your knowledge and experience. I guess the VR3 is for me and not for you.

Agreed.  This is were we started the debate.  My point is caveat emptor.  I
feel that to spend UKP 1,000 on a VR3 is a very poor investment, and I would
spend the money more wisely.  I also feel that the VR3 in its most
conservative setting generates too long a deco for me.

David Shimell
shimell@se*.co* <mailto:shimell@se*.co*> 
DDI: 01932 814096 * Mobile: 07770 282 202 * Fax: 01932 814343
Project Manager, IBM UK Web Server Group, Sequent Computer Systems Ltd,
Weybridge Business Park, Addlestone Road, Weybridge, Surrey, KT15 2UF, UK
registered in England and Wales under company number: 1999363, registered
office as above

-----Original Message-----
From:	Norman Woods [SMTP:normanwoods@no*.fr*.co*.uk*]
Sent:	Tuesday, June 20, 2000 3:12 PM
To:	nick jewson; Shimell, David (shimell); Al Marvelli; Ian Puleston;
John Grogan
Cc:	techdiver@aquanaut.com
Subject:	Re: VR3, Comparison

Hi David
    Glad you are getting some diving in. This month I have abstained from
diving due to my daughters wedding which was on sat. 17th June.(great day
very happy man) That's probably how I became involved in this discussion at
the beginning when someone asked if there was a computer that took all the
latest deco. information into consideration. Normally I would not have had
time to get involved or someone would put forward to the list a more
eloquent statement than I would have on the subject.
There are very few of us who dive fully understand decompression.We rely on
others to research on our behalf. One of the best conversations on this list
recently came from George Irvine when he ran personal profiles and shared
his thoughts on decompression. George's thoughts brought together what he
had learnt from others and what he had done in practice and why. The GAP
programme (by Kees Hoffman with Eric bakers gradient factor) freely
available from the web is an excellent programme for explaining and relating
the differences between algorithms. Combine George's practical experience
and the simple graphics of the Gap programme you should get a very good
understanding of what deco. is about. There are others who have added to our
knowledge but I use this as the most recent example.
    Theory is important but must always be tempered with practical events.
Although the algorithms came from practical research it is research
completed on humans. Some of the fortunates can adjust their schedules and
surface well within the basic Buhlmann programme others on the other hand
need to add a bit more time. The difficult thing that remains is where do
you fit in. Can I reduce my time or will I need more time. How fit are you?
reasonably fit, very fit, athletic. What are you relating your fitness
against? general population, people of your own age, the local tri-athlete
members.(I train Mon-Fri, Running, Karate and weights. I am no athlete)  I
have seen seemingly over weight commercial clam divers ignore tables and get
away with what should have been masses of deco. I have witnessed a thin guy
who runs 5miles a day get skin bends diving within tables. It is only by
your own experiences that you will find where you are in relation to deco.
And remember this can change especially if you have not dived for a couple
of weeks. Remember how sore your body feels after a period of no training,
then you try and do the same circuit you were doing before the lay-off!
I use proplanner because I know were I am on it. I used to use the original
programme which is not as conservative as today's. I have experienced  mild
uncomfortable symptoms on a dive when I have pushed the tables requiring me
to adjust my profile and go with the programme. The deep stops which I only
did on deep dives (dives deeper than 60m) I now do on shallower dives and
have felt a significant improvement (my wife also says I no longer fall
asleep as soon as I get home) Poroplanners algorithms are adjusted from
Doppler research carried out during the Britannic expedition. Extended
midwater stops help significantly the reduction of microbubbles.
I have not used a wrist computer for 8 years. I was using 2 d/timers and 2
sets of slates. Now I only need one set of slates and one D/timer. I am
happy with my schedules from the VR3 as it gives the same schedule I would
have on my slate.You do not learn deco. from a wrist computer neither can
you learn from a D/timer.
David you appear to be on a quest to reduce your deco. even further. As long
as you understand how to correctly do this then I wish you luck. I chose to
reduce deco.(not the only reason) by  using a rebreather and have been using
it for the past 2years.
I ran your dive profile on proplanner then on GAP default GF L .2 GF H .7
then Gap no conservatism.
You can see Gap and Proplanner are similar with Gap giving a few more
minutes on its default setting. GAP with no conservatism is the closest to
your profile.(I ran your friends profile'VR3' on the computer and it was
spot on, he followed his plan)
Basically it is back to opinions, there are enough programmes out there it
is up to you. The reasons why you choose one and not the other is based on
your knowledge and experience. I guess the VR3 is for me and not for you.

Proplan
M     T     Gas
55    27    15/50
39    30
31    32
24    33
21    35    50% o2
18    38
15    41
12    47
  9    56
  6    89    99% o2
Surf  93mins total

Gap Gf L .2  Gf H .7 default setting can adjust to reduce amount of deco.

55    27    15/50
36    30
33    31
30    33
27    37
24    40
21    42    50% o2
18    46
15    49
12    55
  9    64
  6    94    99% o2
Surface 98mins total

Gap No Gradient factor

55    27    15/50
18    32    50% o2
15    35
12    38
  9    44
  6    63
Surface 67mins total

Take care all
Norman
---------------------------------------------------------------
Norman Woods
Coleraine N Ireland
normanwoods@no*.fr*.co*.uk*
www.norglen.freeserve.co.uk
----- Original Message -----
From: Shimell, David (shimell) <shimell@se*.co*>
To: Al Marvelli <ajmarve@ba*.ne*>; Norman Woods
<normanwoods@no*.fr*.co*.uk*>
Cc: <techdiver@aquanaut.com>
Sent: Monday, June 19, 2000 11:04 AM
Subject: RE: VR3, Comparison


> Al
>
> An update on our VR3 discussions from last week...
>
> Sadly, we have sunny but windy conditions this weekend in the UK and only
> managed one dive to 56m on a very well dived wreck.  I kept the dive short
as
> I had a wee problem (as it were) with my P-valve :-).
>
> I was not diving with the diver with the VR3, but from discussion
afterwards
> he did a slow descent (i.e. less ABT, since he left on a his scheduled RT)
as
> the shotline had been pulled down by the preceding divers.  He left at 23
> minutes RT with a total in water time of 75 minutes.  I believe "zero"
safety
> was used on the VR3.  The VR3 diver was diving 16/44 and 40% and 80% deco
> gasses.  Most of the profile apparently was at the max depth.
>
> In contrast, I did my usual descent reaching the bottom just after 3
minutes
> and leaving at 27 minutes RT.  I did the following deco:
>
> (Key: Depth Stop/RunTime)
>
> 55 24/27 Actual on 15/50
> 33 1/30 1
> 30 1/31 1
> 27 1/32 1
> 24 2/34 1
> 21 1/35 4 on 50%
> 18 2/37 1
> 15 2/39 2
> 12 3/42 3
> 9 5/47 5
> 6 14/61 13/61 on O2
>
> (The second column is what my tables said, the third column is what I
> executed.)
>
> I took 4 minutes to reach the surface from 6m, thus arriving at 65
minutes.
> My max depth was 56.4m and spent most of the time scootering around the
max
> depth, but ascended over the wreck twice.  I dived 15/50, 50% and O2.
Thus I
> had 10 minutes less deco for at least 4 minutes longer on the bottom.
>
> Had I left the bottom at 23 minutes, like the VR3 diver, following a
normal
> descent I would have left the 6m stop at 51 minutes, hitting the surface
at
> 55 minutes exactly 20 minutes less deco on this short dive.
>
> To make a further comparison, were I to dive the same gasses as the VR3
diver
> (16/44, 40% and 80%), arrive on the bottom at 3 and leave at 23, I would
have
> the following profile:
>
> 55 20/23
> 33 1
> 30 1
> 27 1
> 24 1
> 21 1
> 18 1
> 15 1
> 12 2
> 9 4
> 6 11/45
>
> and reach the surface at 49.  So the closest comparison without looking at
> the actual downloaded profile is 75 minutes in water vs. 49 minutes for
the
> same bottom time.
>
> I'll have a look at the VR3 diver's profile when he downloads it, but
expect
> that the swim time down would reduce the ABT and therefore the difference
in
> deco would be greater.  Naturally, I felt great after the dive, apart from
> slight discomfort from a rib which had been injured in an earlier
non-diving
> sports injury.
>
> Perhaps Norman may now better understand my comments:
>
> >I refer to VR3s as wrist weights.  If you prefer to spend your dive time
> >doing deco rather than on the wreck, then the VR3 is the dive computer
for
> >you.
>
> David Shimell
> shimell@se*.co* <mailto:shimell@se*.co*>
> DDI: 01932 814096 * Mobile: 07770 282 202 * Fax: 01932 814343
> Project Manager, IBM UK Web Server Group, Sequent Computer Systems Ltd,
> Weybridge Business Park, Addlestone Road, Weybridge, Surrey, KT15 2UF, UK
> registered in England and Wales under company number: 1999363, registered
> office as above
>
> -----Original Message-----
> From: Shimell, David (shimell) [SMTP:shimell@se*.co*]
> Sent: Tuesday, June 13, 2000 9:30 AM
> To: Al Marvelli; Norman Woods
> Cc: techdiver@aquanaut.com
> Subject: RE: VR3
>
> Al
>
> From some comments made after a Trimix dive, the deco was similar to
Proplan
> with 10% safety.  The VR3 was set to zero safety.  We have some 80m stuff
> coming up this weekend, so I'll have a chat with the owner of the VR3.
>
> David Shimell
> shimell@se*.co* <mailto:shimell@se*.co*>
> DDI: 01932 814096 * Mobile: 07770 282 202 * Fax: 01932 814343
> Project Manager, IBM UK Web Server Group, Sequent Computer Systems Ltd,
> Weybridge Business Park, Addlestone Road, Weybridge, Surrey, KT15 2UF, UK
> registered in England and Wales under company number: 1999363, registered
> office as above
>
> -----Original Message-----
> From: Al Marvelli [SMTP:ajmarve@ba*.ne*
> Sent: Tuesday, June 13, 2000 8:28 AM
> To: Norman Woods
> Cc: Shimell, David (shimell); techdiver@aquanaut.com
> Subject: Re: VR3
>
>  i dont have access to one of these and i was wondering what kind of
numbers
> it
> spits out.
>
> David maybe you could hunt down a profile or two from one of these other
> users?
>
> rgds,
>
> Al Marvelli
>
> Norman Woods wrote:
>
> > David
> >     Its only opinions do not take it to serious. You Play with your toys
> and
> > I will play with mine. Ask your friend if you can look at his programme
> Ver.
> > 3. If your happy with the results I am happy.
> > Take care
> > Norman
> > ---------------------------------------------------------------
> > Norman Woods
> > Coleraine N Ireland
> > normanwoods@no*.fr*.co*.uk*
> > www.norglen.freeserve.co.uk
> >
> > > >Strange I find it quite the opposite. Never did like the Oceanic. Did
> you
> > > >Know the VR3 has a default safety which you can adjust.
> > >
> > > I am aware of the adjustable so-called safety.  I understand that the
> > diver
> > > using the VR3 had the so-called safety set to zero at the time.
> > >
> > > Perhaps you'd like to publish a download profile for a typical wreck
dive
> > and
> > > we can compare your VR3 profile with what I would do on tables.
> > >
> > > David Shimell
> >
> > --
> > Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
> > Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
>
>
> --
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