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PRESS RELEASE BY KIM McCOY
“A man gazing at the stars is proverbially at the mercy of the puddles in the road.”
The descent was only slightly abnormal, but abnormal. A ‘wing’ had been fitted to the camera on the sled to keep the sled from rotating. The wing created a lateral (sideways) force*. As the sled descended, the continual lateral force of the wing pushed sideways along its entire cable’s length. Below, the concrete bottom weight (15 kg in water) was swung to the side. The cable extending from the boat to the concrete weight was inclined (not vertical). There was minimal ocean current. The data indicates an unusual increase in speed during the last 10 meters of the descent.
*Calculated sideways force ~10 kg at a descent velocity of 1.6 m/sec.
The ascent was unusual compared to other dives I have observed. The return to the surface was delayed several times. The cumulative delay time was more than 60 seconds. The causes for delay are associated with decreased buoyancy and increased drag. The increase in drag was a result of the ascent-bag sliding along the inclined cable. During mid ascent (164 to 120 meters depth) there were several short periods (~2 secs) during which the ascent almost stopped. At 120 meters, 3:50 into the dive, the ascent gracefully slows and Audrey, like a ‘leaf in autumn’ begins to descend. Blackout. She descended for only 15 seconds before Pascal Bernabe intercepted and reversed her descent. Audrey was transferred to Pipin and returned to the surface at 8:38.
Time depth plot of 12 OCT 2002 dive (divide samples by 4 to get seconds) (Training dives)
My opinion is based upon the following sources of information:
Instrumentation: (used during Audrey’s dive into history)
OS500 D (on Audrey, oceanographic instrument 4 measurements per second e.g. 4 Hz)
(Accuracy +/- 0.05 meters, useable resolution 0.005 meters)
(Maximum data acquisition rate 1000 samples per second e.g. 1000 Hz)
(Corrections made for water density and local gravity)
Mares dive computer (time and depth computer on Audrey’s wrist)
Aqualung dive computer (max depth recorder and elapsed time, on Audrey’s leg)
UWATEC (3 worn by Pascal Bernabe on his wrist)
Dive computer (1 worn on Wiki’s wrist, Mares)
People: (all personally interviewed by Kim McCoy)
Audrey Mestre (I have know Audrey and her parents for 6 years)
Pascal Bernabe (Mixed gas diver 170 meter)
Eduardo ‘Wiky’ Orjales (air diver 90 meters)
Denis Bourret (air diver 60 meters)
Matt Briseno (surface support diver 0-30 meters)
Orlando ‘Tata’ Lanza (surface support diver 0-30 meters)
Carlos Serra (IAFD)
Francisco ‘Pipin’ Ferreras (IAFD)
Bill Stromberg (AIDA observer, surface observer, in water)
Robert Margaillan (photographer and journalist, longtime friend of Audrey)
Eddie Matos (first aid, EMT, on catamaran)
Other
Historical (data from training and record dives from 1995 to present)
Videos (from training and record dives 1995 to present, sled and mid-water)
Still photographs (from training and record dives 1995 to present, sled and mid-water)
(Film and digital images with embedded time codes)
Mathematical tools (algorithms used in hydrodynamics)
Tape measures (correlation of sled cable length on land and of depth gauges)
Weights (estimated weights of the components of the sled, weights, cable, etc.)
Observed similar events (Pipin’s Cozumel blackout dive, Pipin’s Cabo San Lucas aborted 130 meter dive,
Audrey’s Canary Island extended time at depth, Pipin’s aborted dives
All events instrumented by McCoy
Descent: 1 min 42 secs count down of -5 to zero minutes (completed by Carlos Serra)
Zero: (Audrey delayed a few seconds after zero was reached, commensurate with prior dives)
(Audrey was focused; no indications of excessive stress or discomfort)
Time: 0:00 (Zero all references to time referenced to Audrey’s complete immersion below surface)
Time: 0:04 (V=1.50 m/sec)
Time: 0:31 (depth 50 meters attains maximum V=1.90 m/sec)
Time: 1:00 (depth 100 meters V= 1.75 m/sec)
Time: 1:34 (depth 159 meters V=1.62 m/sec Pascal bangs on his tank as signal of approach)
(Cable ‘impulse’ of unknown origin; initially believed (falsely) to be impact with diver)
(Slight increase in V ~+0.30 m/sec, perhaps from change of sled or body positions)
Time 1:42 (large cable ‘impulse’ supported by all sources as sled reaching bottom of cable)
Ascent: from 1min 43 to 8 min 38 secs.
(Visual observations of Audrey indicated normal bodily actions, no distress)
Time 1:59 (depth 169 meters, upward increased V~0.30 m/sec normal for initial ascent from depth)
(Surface waves and boat motions visible in pressure record T=~ 7 seconds)
(Audrey does not request assistance)
Time 2:12 (depth 165, V=essentially 0, waves clearly visible in record indicating cable interaction)
(Ascent is impeded; Pascal attempts to add gas to ascent-bag)
(Audrey does not request assistance, appears calm)
Time 2:42 (depth 164, V=0.6 begins to rise uniformly)
(Pascal observes Audrey ascending above him for 2-3 secs)
(Pascal resumes his ascent; Audrey has ascended above him with ascent-bag)
Time 3:00 (depth 153, abruptly slows to V=0.0 for ~2 secs, then resumes V=0.8
(‘Breaking’ of ascent-bag on cable, several other locations during ascent)
Time 3:30 (depth 136, V=0.8 fairly constant velocity during this rise portion
Time 3:50 (depth 120, V=0.0 ascent slows and begins to descend)
Time 4:05 (depth 124, V=-0.3 descending when Pascal reaches Audrey 15 secs after unconscious)
Time 6:00 (depth 91 V=0.0 no longer safe for Pascal to ascend, prepares to transfer)
Time 7:03 (depth 89, V=0.5 ascending Audrey transferred to Pipin for final ascent)
Time 8:38 (depth 0, V=0.0 surface reached)
Time 9:39 (Audrey removed from water and placed on port side of catamaran)
Estimated small boat transfer time to beach 5 to 6 min. (based on my stopwatch earlier that day)
Audrey was a well-trained athlete. I have come to the following conclusions about the accident.
1) The ascent bag provided inadequate lift (much less than normal) at bottom
2) There was inadequate tension on the cable (bottom weight ~15 kgs + cable weight ~23 kgs)
3) Wings (400 cm2) on the sled camera caused an unexpected force (~10kg sideways) on the cable.
4) The descent has an increase in speed just prior to bottom arrival, associated with the relative location of the bottom weight on the cable as the sled approached the bottom. Observed cable ‘impulse’ could be associated with the sled-cable-weight interactions.
5) Ascent bag upper bearing insert was marginal (slight damage) which increased drag.
6) An attempt to add gas to the ascent bag was made by Pascal Bernabe
7) The ascent was impeded by hydrodynamic instabilities at low speeds. The ascent was non-vertical, which caused ‘braking’ of the ascent bag on slack cable (at regular surface wave intervals).
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