QRSS Report on Diver that drowned in Cenote Odyssey - Tulum, Mexico

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Manatee Diver

Stop throwing lettuce at me!
ScubaBoard Supporter
Reaction score
Tampa Bay, FL
# of dives
None - Not Certified
I looked but couldn't find the original thread. Once again the folks in Mexico have proven that transparency with their excellent factual report, and now with a full speculative report being released very quickly.

The meat and potatoes of the report. The report has maps and locations marked, along with information on the recovery and the route that was taken by the diver.
What happened to the victim?
What we know. The diver was found within an arm’s length of where he had
“dropped”/attached his stage tanks to the line. Both sidemount tanks were
attached to his body. Both of these tank valves were fully open, and both
tanks were empty. He was positioned horizontally and face down. His helmet

was in place, and his mask was on his face (no blood was in the mask).
There were no apparent signs of struggle.
The stage tank valves’ positions raise additional questions as to what may
have occurred. Both tanks were attached/clipped off to the guideline per
standard protocol with hoses and regulators stowed properly.
One stage tank was found empty with the valve inexplicably fully open.The
second stage tank’s valve was closed, and the tank was pressurized with
170 bar/2500 psi of remaining gas. The DPV was clipped to the line at the
same location and was functioning.
The diver had perished within an arm’s length reach of his tanks and DPV.
He had a survey slate in his pouch and a wrist slate with many sheets of
information. He had most likely been working and re-surveying the lines near
where he “dropped” the stages and DPV. But we have no information about
his dive plan.
Equipment was functioning properly. The recovery team checked the
diver’s equipment with the police investigators as witnesses. Three of the
tanks were completely empty as described, and one still contained
170bar/2500 psi of gas. Analysis confirmed that the remaining gas was 32%
nitrox as marked on the tank. The team checked for malfunction by
connecting all of the regulators to a full tank. There were no signs of
malfunction of any of the regulators, hoses, or o-rings. They were all of a
high-quality brand and looked very new and well maintained. Lights all were
Reconstructing the dive
Martin and Gustavo conducted two additional dives to gather more
information about the diver’s route and navigation. Their second dive
followed the deceased’s route based on the information retrieved from his
dive computer profile. They were able to find the missing last piece of
equipment, an Mnemo (mapping and survey device) that the diver had used.
During their dives, they were able to recreate his dive profile, which matched
the time, distance, and depth retrieved from his dive computer.
We believe that the diver had set up a “base camp” from which he would be
exploring and mapping the lines in that section of the cave. He would have
scootered in using a stage tank and may have clipped this tank off before
starting a swimming dive using the other stage bottle. He would have left his
DPV on site, returning to “base camp” after mapping the adjacent lines.

During one of those consecutive not-so short dives, he returned to “base
camp” to leave the second stage tank. We hypothesize that he recalculated
his remaining gas at this point. He continued to survey, probably because he
was familiar with his surroundings. At some point, he placed the third jump
(navigational decision) and proceeded to explore that section of the cave
using his sidemount tanks with the goal of completing the mapping of that
section of the cave.
The dive profile indicates that he had followed this jump line for about 10
minutes, during which time he found a promising crack leading to a deep
unexplored section of the cave. He decided to continue to what was the end
of the existing line (confirmed by the recon dives that were made). Then—
using only his two sidemount tanks—he proceeded back toward the “base
camp” using the Mnemo to complete the cave line map. His sidemount tanks
by this time would have been at his turnaround reserved pressure.
On the return trip, he decided to take a look into the crack. In this unexplored
section, he found himself in a very narrow vertical restriction (a confined
space that allows room for only one diver). Contact with the cave caused a
silt out and zero-visibility situation (confirmed by Gustavo and Martin on a
recon dive). These stressful events would have caused him to increase his
gas consumption.
Due to this unexpected situation, and in combination with the depth, the
diver most likely drained one of his sidemount tanks. He managed to find his
way out of the crack, rushing back toward his stage tanks and DPV. On the
way he dropped his Mnemo, which was later found just a few meters from
him. He drowned only one foot/30 cm from his partially full stage tank and
DPV, which would have gotten him out of the cave.
Hypotheses and Analysis
We hypothesize that the victim may have recalculated his available gas from
the “base camp,” raising the question of aggressive gas management as a
contributing factor This is a not-uncommon practice to maximize bottom time
for work. But recalculation requires caution and attention to managing the
risk: For every recalculation and restart, the “on board” reserve gets smaller
and smaller.
Why was a stage tank fully drained with the valve open but properly stowed?
We knew this diver to be conscientious. He would not have drained a tank
dry and risked damage to the cylinder and regulator. Possibly he used most
of the gas while surveying and forgot to close the valve. Or the attached

regulator may have free flowed and drained the tank. This remains one of
the accident’s unanswered questions.


  • Odyssey cave fatality-FINAL.pdf
    518.3 KB · Views: 70


Scuba Instructor
Reaction score
# of dives
500 - 999
My condolences. So close....

Top Bottom