
THE SPRING OF TH MILL at CASTELCIVITA 2003
by Roberto Rinaldi
(Published in
the magazine "Mondo Sommerso")
The
appointment with the Spring of the Mill at Castelcivita has become annual
tradition, this time, because of the circumstances, it is reduced to two weeks
instead of the initially programmed three weeks. The one week of delay was lost
in the beginning with waiting for the bruises and scratches of Gigi after an
ugly fall while he was exercising with the bicycle healed and became compatible
with the programmed dives. The
lost week subsequently could not be recovered because of the intrinsic
conditions in which the spring has been found.. The strong dry period has in
fact contributed notably to the lowering of the level of the water at the entry
and even if this could make hope for a diminution of the current in the deep
zone of the cave, on the other hand immediately after the first descents we
realize, that the visibility which initially is already only about 5 meters at
the return is reduced to one meter. We remember that during the explorations of
the preceding years a visibility of 15m which at the return was reduced to not
less than 5 meters could be enjoyed. Nevertheless a substantial novelty has has
marked a turn in the exploratory system of this year and more and more it will
characterize the future explorations: Gigi has begun to use a double passive
semi closed circuit: the Recy01. Naturally this passage has not been without
questions and uncertainties which have been resolved during the use and thanks
to the critical evaluation of the handycaps as well as with the support of the
traditional safety rules: while he was preparing the for the push dives, while
being at over -80m of depth, Gigi has found some serious problems of respiraton
with the rebreathers that have forced him twice to return in open circuit until
level of the decompression stops. Only the second time when at -70m he did not
succeed to breathe from the rebreather anymore, and kept on descending further
to -115m in open circuit, and observing with calm, he found out that the problem
was connected with the gas output and that the regulators of the rebreathers
were completely collapsed.. After checking that the gas feeding of the circuit
was correct, he noticed that in ascent the regulators returned to function
normally when at the first decompression stop at -65m he then tried with success
to use the circuit again. Passing stop after stop during the decompression, with
time available to to think, to reflect, to investigate, which there is in
abundance, at the end of the dive Gigi had already discarded the hypothesis that
the regulators was adjusted incorrectly; rather the malfunction had to be seeked
in the anti-freeze. Once out of the water there is the solution: the anti-freeze
were empty. Explanation: the anti-freeze of metal mounted by Gigi, if not filled
with liquid, prevents the pressure of the water to work on the membrane of the
first stage and therefore once reached the 8,5bar (-75m) of the setting, it is
not possible to breathe anymore. These regulators with the anti-freeze were used
by Gigi in the June expedition at the Ural in Russia: not having found alcohol,
in that occasion Gigi had filled the anti-freeze with glycerine, a liquid much
denser and tiresome to eliminate than the usual alcohol. The little remained
glycerine in this way at a quick control had made believe, that they were full,
while in reality they were desolately empty.
The times devoted to the preparation of
the exploration are therefore also involved by this delicate but altogether
fruitful experience to realize to never let space for superficiality, there are
always corners of the own " experience " to illuminate.
The faith in the new apparatuses loses a
a little of the initial shining and to face the most advanced dives Gigis
reflects about the mediation among the past and the future, therefore his push
dive will be based on the use of only one semi closed circuit and the return
will be in open circuit. The second week, on the 5th of august, Gigi carries an
emergency tank and lays out line to the most distant possible: the preceding
line is covered by the dunes of sand and has to be removed; it has rained the
day before, the visibility is subsequently reduced and doesn't allow ro
recognize the section well, but only through some principal characters of the
tunnel. This however is already a distant dive with which the function of the
new apparatus is confirmed, which this time functions perfectly, so that Gigi,
after having remained thirty minutes in the deep zones, returns and continues to
use the rebreather also during the decompression.
The basic considerations which point out
are significant: the total gas consumption with the use of the rebreather has
been 4800 liters; using the traditional open circuit, for the same dive around
30.000 liters of gas would have been needed.
Besides the reduced emission of bubbles
have not detached big quantities of clay from the ceiling and the conditions of
the visibility have been benefited of it.
For the push dive the preparations are
reduced marvelously: in fact the emergency bailout tanks for the decompressions,
as not having been used, are already there and it is not necessary to prepare
anything. However in any case the prudence suggests Gigi to always use the
rebreather with traditional support of the usual tanks. He starts, everything
goes smooth, he succeeds in pushing the limit of exploration about thirty meters
further, descending to -120m: unfortunately the great hall where he has arrived
has a very bad visibility and to despite of the attempts to find a reasonable
continuation in the various directions all efforts are fruitless. When he
decides to return definitely, he is engaged to recover all the cylinders
predisposed along the way: using the rebreather, the problem of the autonomy is
exceptionally reduced, the stops of decompression are lengthened but also for
this need there is ample space within the autonomy.
The 8th of August we return
home: from the point of view of pushing the limit of exploration the results
have only been acceptable in consideration of the intrinsic conditions of the
spring, nevertheless a new great horizon full of expectations for the future has
been opened. The use of this experimental rebreather, verified, brought to a new
absolute depth of -120 meters, has shown how much in the future always a smaller
employment of tanks and carriers will be required, it has shown how much faster
and agile the explorations can be faced and it is only the matter of time, a
really brief time.

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