Maldives Dive Accident

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I’m writing this while flying back to LAX from New York. And since the flight is almost six hours, I’ve got time to muse. My hope here is not to speculate, but offer you some guideposts to look for as more information becomes available. I’m guessing you’ve heard about this by now but if you haven’t . . .

MALDIVES DIVE TRAGEDY – The short version of this is that a few days ago, five Italian divers made a dive to a cave system in the Maldives at a stating depth of 165’ and none of them came back. All five died. Additionally, a military-trained rescuer died during the government-coordinated attempt to retrieve the bodies. So six people in total are dead and the obvious question is: Why?

I want to start by echoing a caution from Dan Orr which is that we shouldn’t be speculating. Essentially, no real facts are known other than that six people are dead. There a wealth of information we simply don’t know at this point and it’s not really beneficial to start guessing as to what happened. But as we learn some more, there are things you should be thinking about and my hope here is to point some of them out.

I’ve never dove these caves before. WAAAY beyond my comfort zone both because of the depth and that they are caves, aka overhead environment. What I’ve read about them is that they start at a depth of 165’ and may get as deep as 200’. (I’ve also seen 200’ as the starting depth.) There are three inter-connected chambers. It is unclear where the first body was found but locations of all the victims relative to each other can provide some clues to as what happened.

So the big question to answer is regard to the first victim location is: Why was he found alone? Did he get separated from the rest of the group? Was he trying to find a way out to get help? Did he get separated and was trying to find the group? Had he found a way out and was going back to find the group and lead them out? Lots of possibilities.

It’s also not known as to the certification level of the group as a whole. It seems a couple of them were involved in some scientific research projects in the Maldives but this dive wasn’t part of that and seems to have been a pleasure dive rather than scientific working dive.

So that begs the question as to whether they were qualified to do the dive or not. Simply from a standpoint of Maldivian diving regulations, there’s a 100’ depth limit for all dives in the Maldives. So there’s no question they were in violation of that.

It is unknown if any or all of them were certified/qualified for a deep tech dive let alone a deep tech cave dive. Many people have said most of the group was very experienced with one of the divers having over 5,000 dives. But that doesn’t mean you’re ready to go into caves, let alone deep ones.

Another big question is how they were equipped and what were they breathing.

One post on ScubaBoard says the boat they were on (the Duke of York) said they were all diving on single 80cf tanks. If that proves to be true, that’s potentially problematic and might point to out-of-air as a culprit.

Remember that the starting depth was 165’+, which is 6atm. That means you’re going through your air six times faster than you would at the surface. (If they got to 200’ then that rate would increase further.) Based on studies I’ve done over the years, most experienced divers have a surface consumption rate of around 0.5cfm (cubic feet/minute). So at 165’, that would be a consumption rate of 3cfm (0.5 x 6). That means an 80cf tank, without accounting for air consumed on the way to depth or saving some for an ascent or deco stop, would last around 27 minutes. If you allow for 500psi to get to depth and you want 1000psi for the ascent and deco that gives you 1500psi or 40cf of gas to use at depth, so 13-14 minutes of cave exploration time. (And that’s likely not enough – better numbers might be 1000psi down and 1500psi to come back up, which then leaves you 500psi, or about 17cf of gas to work with which would last about 6 minutes.) If they got lost, or lights failed, or the cave silted out, or whatever, now add in some anxiety which is going to accelerate gas supply depletion.

But again, these are possibilities, not facts. We won’t really know anything until all the equipment is recovered and authorities can see if there was any gas left in the tanks and if it was air or nitrox or trimix or something else.

A number of people have speculated on-line that oxygen toxicity may have come into play. Again, without know what they were breathing and without doing an autopsy on the bodies, that’s something that can’t be claimed with any level of certainty. But let’s look at ox-tox in general.

When I got certified in 1978, the rule of thumb was that you wanted to keep the partial pressure of oxygen below 2.0atm. Nowadays, we tend to use a more conservative 1.4atm with a contingency of 1/6atm. So when you’re diving nitrox 32% today, that means a depth limit of 111 feet. And the group in general, plus the lead researcher, likely would be experienced enough to understand that nitrox 32% (which is what most boats who provide nitrox pump) wouldn’t be a good choice. So if they dove this on air, does that rule out oxygen toxicity?

As I mentioned, when I got certified in, the accepted limit was 2.0atm. On air (20.8% O2), that was a depth of 284 feet. But when you use 1.4atm as the limit, now that max depth becomes 189. So, if they were diving air, they would have at best been skirting the edge of toxicity if diving on air. So it may be that, if they were diving on air, oxygen toxicity could still come into play. But you’d also have to realize that if this hit one or two of them, the symptoms are rather violent convulsions where you basically spit your reg out and start inhaling water, would it have hit all five at once? Could others have been trying to rescue a couple of them and it all went south? In looking at accidents over the years, there are certainly examples where one diver gets in trouble, their buddy tries to help, and they both end up dying. But five people? That alone raises many questions that still can’t be answered.

There’s more to discuss but I’ve gone on long enough and I think I’ve hit the main points. But as you can see, this isn’t a simple accident scenario nor will the answers be forthcoming quickly. What it does seem to underscore is that five divers decided to make a dive that was beyond their likely training, possibly without the right equipment, and all five of them died. That in and of itself, regardless of the reasons, should be an endorsement to dive conservatively and within your limits.

It also turns out there was a sixth member of the Italian group who chose not to do the dive that day and (obviously) didn’t die. And that person is the living embodiment of something I’ve said to you many times over years but which this horrible accident really drives home: You never get hurt on a dive you don’t make.

Please dive safely and cautiously so we can continue to have these weekly discussions.

- Ken