All

A few weeks ago I posted a note on my recent dive with Greg Maud at Badgat,
South Africa.  Since then the has been extended to the end of the 110m
level.  Here is an update of my recent dive with Mike Fowler for those
interested.

On my previous dive on 21 March 1999 the end of the line stood at 140m from
the bottom of the shaft or 380m from the cave entrance.  This dive was
planned to be short due to my leaky dry suit.  Suit problem resolved, a
longer in water time could now be contemplated.

Unfortunately, my previous dive partner, Greg Maud could not make it but
fortunately Mike Fowler of the Badgat Dive Centre was available to dive.
The objective was to lay line to the end of the at 110m tunnel.  To this
end, we planned a maximum of 30 minutes bottom time and carried ample spools
of line.  The dive on 3 April 1999 went something like this...

The gasses I used were as follows:

11/59 bottom gas in twin 15 litre cylinders and a 9 litre stage.
19/35 travel and deep deco gas.
35% travel and deco gas.
50%.
O2.

Mike dived CC but also had the following cylinders staged for use only in
case of failure:

35%.
50%.
O2.

For the bottom, Mike also carried an OC stage of 11/59 bottom gas again in
the case of failure.

In addition, we staged deco safeties as follows:

50%.
O2.

Setup divers pre-staged 6 cylinders of deco and safety deco gasses and the
O2 was placed at our point of entry.  I travelled in on 35%, 130m along the
primary line at 18m to the "green door" restriction, arriving at the shaft
6+ minutes into the dive.  Visibility was a poor 3m due to other divers
spoiling the conditions.  We waited for the run time to reach 10 minutes and
descended, dropping past the staged 50%, continuing down to 38m to drop the
35% and pick up my 19/35 gas.  We left 38m at 14 minutes on schedule and
descended in excellent vis to 68m where I dropped my 19/35 gas and switched
to my stage of 11/59, 16 minutes into the dive.  We reached the bottom of
the shaft a few seconds behind schedule at 18 minutes.

The tunnel at 110m had excellent visibility of about 30-40m and we started a
swim at a good pace (British understatement) following the existing line.
As we reached the inclined shaft on the left, 100m into the tunnel from the
shaft, I hit thirds on my stage and switched to my back gas.  (The inclined
tunnel is inclined at about 45 degrees and the size of a garage door and has
yet to be explored.)

We reached the end of our old line and I tied on my spool of line to the
loop I left a few weeks ago.  The swim continued.  A little further on we
reached a door on the left with a large room the other side.  This is
unlikely to go beyond the end of the tunnel but interesting to explore
another time.  Very soon we reached the walled out section of the tunnel,
190m from the start of the base of the shaft and 430m from the cave
entrance.  This proves that the tunnel extends entirely under the pit above.
The whole length of the tunnel was 2-3m in width and about 2m in height.

We tied off.  On the return Mike had a good look into the room now on the
right and later confirmed that it is of reasonable size.  Thoughts are that
this could be explored on a subsequent setup dive.  After looking at the
included shaft area once again, we reached the shaft 35+ minutes into the
dive.  We started deep stops once I reached my deep deco gas of 19/35 at 68
m. Deep stops were about 1 minute every 3 metres.   My first "mandatory"
stop was at 45 m and I did about 8 minutes between 68m and 48m, adding a
further minute to each of the 45 and 42m stops.  This was mostly because I
am lazy and adding 10 to my run times is easier than adding 8!

We exited the cave together nearly 90 minutes into the dive and swam to the
shot line at the entry point.  Drinks were awaiting including a nice warming
soup brought down by our support divers.  It must have been a funny sight
watching Mike and myself alternately breath-for-gulp, buddy breathing O2 and
buddy drinking soup.  Thank goodness for my pee-valve!

I did 5 minutes of back gas breaks every 20 minutes and counted these as
deco.  The schedule for 110m, 18 minutes ABT was as follows:

68-48	1	- deep stop every 3 m - 19/35
45	1+1	- 19/35 (Abyss Mandatory + 1 minute deep stop)
42	1+1	- 19/35 (Abyss Mandatory + 1 minute deep stop)
39	1	- 19/35 (Abyss Mandatory)
36	2	- 35% (Abyss Mandatory)
33	2	- 35% (Abyss Mandatory)
30	2	- 35% (Abyss Mandatory)
27	3	- 35% (Abyss Mandatory)
24	4	- 35% (Abyss Mandatory)
21	5	- 50% (Abyss Mandatory)
18	6	- 50% (Abyss Mandatory)
15	9	- 50% (Abyss Mandatory)
12	12	- 50% (Abyss Mandatory)
9	21	- 50% (Abyss Mandatory)
6	70	- O2 (Abyss Mandatory)

Total RT was 197 minutes on surfacing.

I used Abyss 2.02 (125 algorithm) to calculate the "mandatory" stops which
were not shaved, but back gas breaks were included as deco in the 70
minutes.  Interestingly, had I programmed in the deep stops, I would have
had an additional 16 minutes deco to do, which on top of the 10 minutes back
gas breaks would have extended my dive by 26 minutes.

I was amused to get out of the water after 197 minutes, a full 15 minutes
ahead of Mike who was diving constant PPO2 rebreather.  However, Mike had
the last laugh when it came to the gas bill.  My RMV was a-high-for-me 17 on
the bottom, 11-13 on deco gasses except for O2 which was 7 litres/minute.

I used roughly than half of my available gas, excluding safeties which were
untouched.

I felt fine after the dive apart from being cold (but not so cold as to
shiver) and having a headache which cleared after 2 hours.  I think the
headache was due to cold rather than poor flushing of the lungs as I never
get a headache on a dive (until now) and I flush my lungs well despite a low
RMV and 3-4 breaths per minute on deco.

I shall not be able to dive Badgat again for a few weeks as I have a wedding
celebration to go to.  I've been trying to get out of it but as it is my
wedding celebration, my wife insists!

David Shimell
Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa.
Email: shimell@se*.co* <mailto:shimell@se*.co*> 
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