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David,
The profile was based on Abyss 100. Amongst some of the physiological
parameters
set included setting
'Smoker' - there was one smoker amongst us, the Course Director.
Age = 41-50. The oldest were the course director & his assistant. The rest
of were all younger.
Slightly overwieght - which Hennie and I were (say by 15kg).
We were all in good physical condition (or appreared so). All were active
divers involved in
Cave and Extended Range diving.
Dive suite and environment, water temp was set 10 degrees celcius, and suite
type was set
to 5mm wet. Hennie & myself were indeed wearing dry suites. I used Argon.
I can't remeber
at this stage what Hennie used for inflation.
As I stated earlier, the actual bottom temprature was 24 degrees Celcius.
The decend rate was kept by all. The average depth of myself, was 106. I
dipped to 108 for
less than a minute in the early stages of the dive. Hennie was always
above me. He did have his
Jon line connected to Steve, but they were in my close proximity, and
always shallower than myself.
I lost sight of them on leaving the bottom - which was on time as per the
profile. The only reason I lost
sight was because I was now concerntarting on my ascend, and not on
Hennie, who was effectively
Steve buddy. Once I started my shallow stops I meet up with Steve &
Hennie who were some 30m
away from me. My support diver pointed me towards them.
There was a 23 hour surface interval between dives.
I hope this answers most of your questions.
Dennis.
-----Original Message-----
From: David Shimell (shimell) [SMTP:shimell@se*.co*]
Sent: 20 November 1997 17:37
To: 'Techdiver List'
Subject: RE: THE FACTS: TDI Training Death, 16 April 1997
Dennis
Thanks for the post. I would like to express my sympathies for the loss
of your friend.
Hoping to understand better the circumstances, I have some questions:
1. Which Abyss algorithm were you using (100, 120, 150)?
2. Although I am not aware of any proven merits of the Abyss scoring
system, 63 still seems low. Prior DCS would contribute to this low score
but not totally, do you know what were the other factors (age, weight,
etc.)?
3. Why did you both exceed maximum depth planned and for how long. Was
this at the start of the BT or the end?
4. What was Hennie's history of exposure to previous Trimix dives and
were these dives asymptomatic of DCS?
5. Were the descent rates followed and what were they?
6. Were the ascent rates followed and what were they?
7. Were there any ascent warnings on Hennie's computer?
8. Did you leave the bottom spot on the run time, early or late?
9. What was the surface interval between the first and second dive and
was this treated as a repetitive dive?
10. Did Hennie have a PFO?
David Shimell
Project Manager, Sequent Computer Systems Ltd, Weybridge, UK
Email: shimell@se*.co*
----------
From: owner-techdiver[SMTP:owner-techdiver@aquanaut.com]
Sent: 20 November 1997 13:33
To: 'Techdiver List'
Subject: THE FACTS: TDI Training Death, 16 April 1997
On 16 April 1997 Hennie Pretorius died while participating on a TDI
Trimix
Instructor course.
Hennie was a friend and diving partner to many.
The TDI Trimix Instructor course was attended by initailly 4 candidates,
but
only three
continuted to complete the dives. There was Hennie, myself and one other
instructor
from Cape Town. Besides the course director, there was also one
Technical
Instructor.
The dives were to be executed on an unknown wreck of the south east coast
of
South Africa near Port Alfred. All we know was the wreck lay in 80
meters
(264')
of water.
As part of the planning, the local NSRI was briefed how to handled diving
emergencies
of this nature. All ships passing by were alerted of the diving
operations
to occur in the
area - we were diving in the shipping lane. A tracer boat was to
accompany
the main
diver boat, skipped by one of the NSRI members.
Dive planning was attended by all the candidates. Using the Abyss
Decompression
Software package the age, fitness levels, weight, age and history of
previous
DCI were
taken into account.
Hennie had DCI some 18 months earlier - this was taken into
consideration.
The
Abyss provided us with a physiological score of 63. All dive profiles
were
to include
J factor of +5 meters on all depths. All the dives were to take place
using
the following gases:
Bottom: Heliair 50:38:12
Travel: Nitorx 32, switching at 40 meters
Deco: Nitrox 80, switching at 6 meters.
The first two dives were executed on the wreck which did bottom at 80
meters.
Some 12 nautical miles off shore. The visibility was poor, no natural
light
and
only 5 meters by flash light.
We, the candidates decided that the last dive we wanted to get closer to
100
meters
(325'), and further off shore were whe should have better visibility.
Due to
the
gradual slope of the bottom, it meant that we needed to double the
distance
of shore to 24 nautical.
The dive was executed in near perfect conditions. A slight swell with
little
or
no wind. There was a considerable current though. The max depth planned
for
was 100 meters (plus the 5% J factor).
The maximum depth attained was 108, by my self. Hennie had reached 105m
as reflected by his Aladin pro after his death. Hennie had teamed up
with
Steve,
the Course Director. The ascend was started on 11
minutes as planned. I lost sight of Hennie for a while but we remeet
while
executing our deco stops. Steve completed his deco stop and excited the
water.
Hennie moved over towards me and continued to stay in the water for
another 2
minutes - this was over and above the required deco schedule. Hennie
was very joyious and happy about the dive - so was I. Bottom temprature
of 24 degrees Celcius and visibility reached the 30 meter mark. No flash
lights were required.
Hennie and I exchanged notes on slates while he was with me. he signled
that
he was going to surface. I stayed anoth 2 minutes before surfacing. I
was
accompanied by one of the support divers at this time.
As I reached the surface, Hennie, some 20 meters away from me shouted he
did not feel well. I sent my support diver over to him. By the time the
support
diver had reached him, he had already lost conciousness. Immediately
evacuation procedure are kicked into place. Hennis was removed from the
water
and loaded into the tracer boat which speed back to the harbour in
Port Alfred. Emergency services were contacted by HF radio, switching to
mobile phones once within working range.
From the harbour, Hennie was flown at low level to the chamber at East
London.
As of the time of hime losing conciousness, it took lees than 3 hours to
get
him
into the chamber.
Hennie never regained conciousness, but during the chamber treatment it
was
noted that he was paralysed on his left side.
After the chamber treatment, he was sent for Brain scans. There were
signs
of air/gas trapped behind the brain.
Hennie was resubmitted for subsequent chamber treatment the next morning.
He passed away while in the chamber.
The final diagnosis was death by misadvanture, created by an AGE.
It was suspected the the AGE occured on the Brain.
The day of Hennie's funeral, TDI(SA) held an independant investigation.
On the panel were Nuno Gomes, Johnny van der Walt and Dr mark Victor.
Present was Roly Naaiman and others. This very much brought all the
great name in SA technical diving together. The investigation was open
to any member of the public who had any interest in the accident.
The investigation revealed that NO HUMAN ERROR OCCURED TO CAUSE
THE DEATH OF HENNIE PRETORIUS.
Department of Manpower investigated Hennies equipment and analysed
the gas used, it proved to be well within the required specifications for
the use there of.
The SA Police Services also completed their investigation and could not
find
any human error in the whole diving or rescue operation.
I trust that this information suffices all your questions that you may
had.
Should you require any further indepth information, feel free to contact
the
TDI(SA) office.
My thanks to Elsie Pretiorius, Hennie's wife for allowing me to extract
some
information from a article that she forwarded for publication
in the Divestyle 9a South African Dive magazine). The article was never
published.
Dennis Harding
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