Indian Spring’s Dive Accident Analisis
By Bill Gavin
Our dive at Indian Springs was the first in a series of exploration dives
that had been in the planning stages for nearly two years. Because of
the unique profile of the cave and the extreme depth at the point at
which actual exploration would take place special decompression
tables had been generated by Dr. R.W. Hamilton. The dive plan
consisted of a 40 minute transit at 140 FSW while breathing an EAN 27
travel mix (27% oxygen, balance nitrogen), a descent and exploration
at 300 FSW using trimix 14/44 (14% O2, 44% He, balance N2) followed
by the return 40 minute transit to exit the cave. The deep working
phase of the dive was expected to last 20 to 25 minutes. The 140 FSW
penetration and exit was done using two 80 cubic feet “stage” bottles,
while the deep portion was accomplished using back mounted double
104′s.
The dive went almost exactly according to plan during the penetration.
The deep section known as “Wakulla Room” was explored in three
different directions. None of these yielded any going tunnel or
evidence of flow. We began our exit at 63 minutes into the dive. At this
time I had 2300 psig in my double 104′s and I assume that Parker had
the same or slightly less. We reached our nitrox bottles at the top of
the room in two to three minutes, began breathing them, and did not
use our doubles again until we encountered the obstruction at what is
known as the “Squaws Restriction.” After picking up our second stage
bottle during the exit, Parker signalled that his Diver Propulsion Vehicle
seemed to be running slow. We linked up via a tow strap and I
increased the speed setting on my DPV to maximum. We were only
about 1500 feet from the entrance, so this did not present a serious
problem.
There is a distinctive arrow marker at the upstream/downstream
junction which is about 500 feet from the entrance. As this arrow came
into view, I remember estimating that our bottom time was going to be
somewhere between 105 to 110 minutes. We made the left turn at this
arrow and immediately noticed that the visibility in the cave had
decreased. The floor was completely obscured by billowing clouds of
silt, but the line was still in clear water near the ceiling. As we got closer
to the entrance, the visibility got progressively worse. Finally, we had to
stop using the DPV and swim while maintaining physical line contact.
When we got to where I thought the restriction should be, the line
disappeared into the sand on the bottom of the cave. We began pulling
the line out of the sand, but some reached a point where it was buried
too deep. Visibility in this area was 1 foot or less. I heard Parker shout
into his regulator, “What’s this?” We backed up out of the low area and
removed our stage bottles and scooters. At about this time, the second
bottle that I had been breathing during the exit ran out. Realizing that
the situation was not going to be quickly resolved, I elected to switch
immediately to my doubles, which still had about 2000 psig of gas.
There were two lines running parallel in the cave at this point. We tried
following both of them, but each time got to a point where the line could
not be pulled from the sand which had covered it.
I secured the line from the reel that we had carried with us to the end of
the permanent line (where it was buried) and tried to search for a way
out. The restriction seemed to be completely blocked with sand and
perhaps rock. The visibility was so bad that we could not really figure
out exactly where we were or what had happened. However, there was
flow and I tried to follow that. After finding no way past the blockage, I
began to have doubts about our exact location. It seemed as though
we must have made some mistake. While Parker continued to search, I
swam about 300 feet back into the cave until I saw the
upstream/downstream arrow marker. Though this marker is quite
distinctive, I had to stare at it for a few seconds to convince myself that
I really knew where we were. I swam back to the point where we had left
our bottles and scooters. Parker was waiting there.
I am not sure how many attempts we made to retrieve the buried line,
but at least 45 minutes passed while we sought in vain for some way
out. At one point Parker showed me his pressure gauge which
indicated about 400 psig of gas remaining in his doubles. He wrote on
his slate, “What do we do?” I knew he was hoping I had some idea, but
the only thing I could think to write back was “Hold on. I’ll go look.”
I went back to search using my reel and sweeping left and right.
Finding no exit, I decided to return to the stage bottles, which at least
had a little more gas to offer. I had been gone for less than five
minutes. When I returned to the bottles, Parker was not there. I found
my second stage bottle, which had about 600 psig left in it. I began
breathing it while trying to think of some plan. After about four minutes
it ran out and I switched back to my doubles, which now had less than
300 psig of gas. With no other alternative, I decided to try one last
effort at finding an opening. As I started back out I saw that another
line had be “Tee’d” into the permanent line. I followed it without really
understanding how it had gotten there. I reached a point at which the
cave seemed to open up and saw something hanging down on the
edge of my vision. As I swam under the object it dimly occurred to me
that it was the second stage of a scuba regulator. By now my doubles
were almost empty and my regulator caught on my manifold as I
passed. I rolled to my left to free it. At this point, I looked up and saw
the permanent line rising at a sharp angle. I realized that I had cleared
the restriction and raced to our decompression bottles, which were
hung at 100 feet. I was almost holding my breath by the time I
unclipped the second stage and began breathing from my first
decompression bottle. Parker was not at the bottles and I realized at
this time that he had drowned.
The regulator that had caught on my manifold was from his doubles,
which he had removed and dragged through the small opening. I had
no idea where Parker was and the visibility was still less than two feet.
Numbly, I waited for support personnel to find me. In the confusion that
followed, many lines were laid throughout the cavern area by our
support divers in attempt to locate Parker’s body. Despite their efforts,
he was not found until the following morning when visibility had
increased to about 10 feet. It had been 60 feet or better when we
started our dive.
During the four hours of decompression that followed, I was gradually
filled in on the situation by our support crew. Without their efforts, I
think I would have gone mad wondering what had happened. For a
long time I did not know if the entire entrance to the cave had collapsed
or if anyone else was missing. I also had no idea what kind of
decompression to follow. Though I fully expected to suffer
decompression sickness, I emerged from the water with no physical
damage. Apparently the fact that we had been shallower than expected
during our deep exploration saved me from that malady.
By Bill Gavin
Our dive at Indian Springs was the first in a series of exploration dives
that had been in the planning stages for nearly two years. Because of
the unique profile of the cave and the extreme depth at the point at
which actual exploration would take place special decompression
tables had been generated by Dr. R.W. Hamilton. The dive plan
consisted of a 40 minute transit at 140 FSW while breathing an EAN 27
travel mix (27% oxygen, balance nitrogen), a descent and exploration
at 300 FSW using trimix 14/44 (14% O2, 44% He, balance N2) followed
by the return 40 minute transit to exit the cave. The deep working
phase of the dive was expected to last 20 to 25 minutes. The 140 FSW
penetration and exit was done using two 80 cubic feet “stage” bottles,
while the deep portion was accomplished using back mounted double
104′s.
The dive went almost exactly according to plan during the penetration.
The deep section known as “Wakulla Room” was explored in three
different directions. None of these yielded any going tunnel or
evidence of flow. We began our exit at 63 minutes into the dive. At this
time I had 2300 psig in my double 104′s and I assume that Parker had
the same or slightly less. We reached our nitrox bottles at the top of
the room in two to three minutes, began breathing them, and did not
use our doubles again until we encountered the obstruction at what is
known as the “Squaws Restriction.” After picking up our second stage
bottle during the exit, Parker signalled that his Diver Propulsion Vehicle
seemed to be running slow. We linked up via a tow strap and I
increased the speed setting on my DPV to maximum. We were only
about 1500 feet from the entrance, so this did not present a serious
problem.
There is a distinctive arrow marker at the upstream/downstream
junction which is about 500 feet from the entrance. As this arrow came
into view, I remember estimating that our bottom time was going to be
somewhere between 105 to 110 minutes. We made the left turn at this
arrow and immediately noticed that the visibility in the cave had
decreased. The floor was completely obscured by billowing clouds of
silt, but the line was still in clear water near the ceiling. As we got closer
to the entrance, the visibility got progressively worse. Finally, we had to
stop using the DPV and swim while maintaining physical line contact.
When we got to where I thought the restriction should be, the line
disappeared into the sand on the bottom of the cave. We began pulling
the line out of the sand, but some reached a point where it was buried
too deep. Visibility in this area was 1 foot or less. I heard Parker shout
into his regulator, “What’s this?” We backed up out of the low area and
removed our stage bottles and scooters. At about this time, the second
bottle that I had been breathing during the exit ran out. Realizing that
the situation was not going to be quickly resolved, I elected to switch
immediately to my doubles, which still had about 2000 psig of gas.
There were two lines running parallel in the cave at this point. We tried
following both of them, but each time got to a point where the line could
not be pulled from the sand which had covered it.
I secured the line from the reel that we had carried with us to the end of
the permanent line (where it was buried) and tried to search for a way
out. The restriction seemed to be completely blocked with sand and
perhaps rock. The visibility was so bad that we could not really figure
out exactly where we were or what had happened. However, there was
flow and I tried to follow that. After finding no way past the blockage, I
began to have doubts about our exact location. It seemed as though
we must have made some mistake. While Parker continued to search, I
swam about 300 feet back into the cave until I saw the
upstream/downstream arrow marker. Though this marker is quite
distinctive, I had to stare at it for a few seconds to convince myself that
I really knew where we were. I swam back to the point where we had left
our bottles and scooters. Parker was waiting there.
I am not sure how many attempts we made to retrieve the buried line,
but at least 45 minutes passed while we sought in vain for some way
out. At one point Parker showed me his pressure gauge which
indicated about 400 psig of gas remaining in his doubles. He wrote on
his slate, “What do we do?” I knew he was hoping I had some idea, but
the only thing I could think to write back was “Hold on. I’ll go look.”
I went back to search using my reel and sweeping left and right.
Finding no exit, I decided to return to the stage bottles, which at least
had a little more gas to offer. I had been gone for less than five
minutes. When I returned to the bottles, Parker was not there. I found
my second stage bottle, which had about 600 psig left in it. I began
breathing it while trying to think of some plan. After about four minutes
it ran out and I switched back to my doubles, which now had less than
300 psig of gas. With no other alternative, I decided to try one last
effort at finding an opening. As I started back out I saw that another
line had be “Tee’d” into the permanent line. I followed it without really
understanding how it had gotten there. I reached a point at which the
cave seemed to open up and saw something hanging down on the
edge of my vision. As I swam under the object it dimly occurred to me
that it was the second stage of a scuba regulator. By now my doubles
were almost empty and my regulator caught on my manifold as I
passed. I rolled to my left to free it. At this point, I looked up and saw
the permanent line rising at a sharp angle. I realized that I had cleared
the restriction and raced to our decompression bottles, which were
hung at 100 feet. I was almost holding my breath by the time I
unclipped the second stage and began breathing from my first
decompression bottle. Parker was not at the bottles and I realized at
this time that he had drowned.
The regulator that had caught on my manifold was from his doubles,
which he had removed and dragged through the small opening. I had
no idea where Parker was and the visibility was still less than two feet.
Numbly, I waited for support personnel to find me. In the confusion that
followed, many lines were laid throughout the cavern area by our
support divers in attempt to locate Parker’s body. Despite their efforts,
he was not found until the following morning when visibility had
increased to about 10 feet. It had been 60 feet or better when we
started our dive.
During the four hours of decompression that followed, I was gradually
filled in on the situation by our support crew. Without their efforts, I
think I would have gone mad wondering what had happened. For a
long time I did not know if the entire entrance to the cave had collapsed
or if anyone else was missing. I also had no idea what kind of
decompression to follow. Though I fully expected to suffer
decompression sickness, I emerged from the water with no physical
damage. Apparently the fact that we had been shallower than expected
during our deep exploration saved me from that malady.
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