I picked this up from Techdiver since it seems to refer to the issue Strike
raised about redundant rebreather technology in Australia.  If it's not
worth more than what it cost,
sorry.

Lee
-----------------------------------

Hi everybody,
I am new on the list. I am interested in  diving with rebreathers. I speak
French so, my sincere apologies for my approximativ English.
I red the website of Reinhard BUCHALY and Michael WALDBRENNER, and I would
like to precise some points in this following message. The translation is
good, because I gave it to a good Friend much better than me for Shakespeare
language...

Some informations about the exploration of the Doux de Coly.

Since 1984 the Doux de Coly is the longest known sump in Europe.

Summary of explorations.
1972. PJ DEBRAS reaches 352 m (a remarkable performance at that time).
1981. Both Claude MAGNIN & Olivier ISLER dive one after the other and MAGNIN
stops at 1750 m.
1984. MAGNIN reaches 2630 m, and ISLER stops at 3100 m (up to this time all
dives are made with open circuits).
1991. ISLER stops at 4055 m using the RI 2000 (redundant rebreather with 3
independant circuits).
1998. ISLER progresses another 250 m (to 4300 m) having unrolled 1150 m of
guide-line, again using the RI 2000 rebreather.
2001. Reinhard BUCHALY and Michael WALDBRENNER reach a distance of 5000 m.

At first, congratulations to Reinhard and Michael for their remarkable dive.
The Doux de Coly carries on and it is not the end. I am very happy to see
that my difficult dive in 1998, where I found the continuation of the cave,
has so successful consequences.

The dive of Reinhard and Michael is reported with a lot of details on the
attractive website www.tekdyk/doux.
Unfortunately, an error appears at the "Welcome" page of the site. The
assertion that  "... all dives were directed using the DIR philosophy
developped by the floridian cave diving team WKPP..." is NOT correct. In
fact, the dive was directed using an intermediate philosophy between that of
DIR and the rebreather redundancy developped by myself (as mentioned on the
site).

The analysis of their dive in fact shows that they both carried 2 X 20 l
tanks on their back (return on open circuit in case of rebreather failure).
They dived as 2 divers together, as in DIR philosophy. Beyond a distance of
800 m, no safety or relay cylinders were placed in the sump. The reason was
that both divers used the double rebreather RB 80. This is undeniably my
philosophy of using Redundant Rebreathers.

It looks evident that rebreather's redundancy, nevertheless thrown back by
the WKPP, was decisive in their successful dive. If they had followed exact
DIR philosophy, Reinhard and Michael both would have used a single
rebreather, and they would have relied on safety cylinders staged far down
into the sump (maybe 3000 m or more), impossible to carry out without a
powerful support team.

As for myself, I am proud to note that, after 11 years of existence, my
philosophy of Rebreather Redundancy, has begun  at least to appear in
extreme diving activity. Even if it is not yet fully accepted, the idea of
Rebreather redundancy goes on, in Europe with Reinhard and Michael and in
Australia with David APPERLEY.

I will end with a note that if Reinhard and Michael plan in the future to
cross the stage of total Rebreather Redundancy (by using an additional small
front mounted safety rebreather) they will both have quadrupled redundancy,
when, during my own solo dives, I had at my disposal triple redundancy. With
such a configuration, the crash risk becomes tiny.

Olivier ISLER