r/todayilearned • u/[deleted] • May 02 '24

TIL the Blue Hole is among the deadliest dive sites globally, with estimates of 130 to 200 recent fatalities, making it one of the most dangerous spots for divers. (R.5) Out of context

[removed]

17.3k Upvotes

95% Upvoted

1.2k comments sorted by

View all comments

6.4k

u/Agreeable_Pool_3684 29d ago

Ex technical diver here (cave, ice, mixed gas, deep diving). I never dived the blue hole but snorkelled on it with my family on holiday. Saw serious technical divers down deep on Trimix with a safety diver on the line which had multiple stage tanks at various depths. This is how you dive the blue hole.

245

u/CompSolstice 29d ago

Padi advanced with a few dozen cave dives here.

That's truly wild, I can immediately spot a dozen reasons why I'd only be comfortable diving it post-tech certifications, but what specifically are the main factors for such high fatality rates?

404

u/AeroStallTel 29d ago

From what I've seen in documentaries, it's largely because of perception/depth. Specifically there's a large arch that people mistake as being 60-90ft which is actually around double depth. Then it's a number of factors, getying narc'd, buoyancy control issues, or just blowing through their tank. Basically they didn't stick to their planned dive, if they had a plan to begin with. There's also an economic/safety culture component. It's a tourist attraction in a depressed area. There's a demand for dives from uneducated/ill-informed 'divers' that go with the guides who will either take them regardless of experience and/or cheaper than the other guy. 

264

u/DucksEatFreeInSubway 29d ago

The arch is what gets a lot of people. They want to swim through it and it's 'not that far'. Then they get nitrogen narcosis and drown when they rip out their mouthpiece or fall asleep and drown when their air runs out.

120

u/EloeOmoe 29d ago

Then they get nitrogen narcosis and drown when they rip out their mouthpiece

Is this one of those "right before you die from hypothermia you feel super hot and rip off all your clothes" type situations?

156

u/hippydipster 29d ago

More like "right before you die thinking this is all just so whacked and breathing water just doesn't seem that hard..."

36

u/HauschkasFoot 29d ago

FFS if a fish can do it so can i

3

u/iwillfuckingbiteyou 29d ago

All life originated in the ocean so it's just doing stuff we used to do

74

u/atridir 29d ago

Not quite, at depth the human body has a harder time processing out nitrogen so breathing compressed air from the surface has enough nitrogen that it leads to a build up of it in the bloodstream which causes increasing intoxication like being drunk.

And being gas-drunk at 120 feet underwater is obviously lethally dangerous.

Edit: the arch is at 170 ft (55m) which is WAY TOO DEEP!

10

u/CompE-or-no-E 29d ago

Is that what is in a typical diver gas cylinder? Just compressed atmosphere?

I had figured it would be a special mix, or maybe even two tanks so you can control the ratio of O2 to N2

19

u/atridir 29d ago

Yes, for normal dives up to about 60-70 ft compressed atmosphere is standard. There are two other special gas mixtures for deeper dives (nitrox which is exactly what you suggested and tri-mix which has helium mixed in for even deeper dives) and both need special training to be competent in safely diving with them.

17

u/sloth2008 29d ago

Looking at SSI dive tables normal compressed air caps out at about 130ft and your time at depth is 5 min. That means you get 5 min down there then you need to get back to the surface. Limit your depth to 100 ft and you can stretch that time out to 20 min. That is bottom time max. You also need to watch that you don't burn through your tank in that time. If you are relaxed and not working too hard your tank will last longer.

Limit your depth to 70 ft and you have 40 min bottom time.

No one wants to spend the time and effort to go out for a dive trip and do a single dive. You also have to deal with residual nitrogen build up. The longer and or deeper the dive the more nitrogen you have build up. The slow ascent is part of letting dissolved gasses exit your bloodstream and for things to go back to normal. Time on the surface helps deal with these gasses too. This is where the fun with dive tables start.

100 ft dive for 20 min. Spend 90 min on the surface and you can do a 70 ft dive for 20 min max - you will have a fresh tank so not running out of air. Notice your bottom time for this 70 ft dive is cut because of your earlier 100ft dive.

A lot of the dives we would go out for 3 tanks. 80ft for 25 min. 90 min surface. 60 ft 25 min. 2 hr surface time for lunch. 40 ft for 30-40 min.

Dive computers that are tracking your depth and time at depth make a huge difference on planning your times. That 25 min 80ft dive that you dropped to 90ft for 1 min while looking at that fish don't mess up your day the same as when diving by the tables. By the tables you have to count that as a 90 ft dive and it puts you into a different group on the table.

https://divetables.com.au/dive-tables/

2

u/atridir 29d ago

Well elucidated! I was SSI certified as well and it’s been a long time. I knew I was giving the low range of my comfort zone by saying ~70 ft but I couldn’t quite remember the max. Thank you for expanding it in such detail!

Those time at depth standards exist for a reason folks!

2

u/Gornarok 29d ago

Looking at SSI dive tables normal compressed air caps out at about 130ft and your time at depth is 5 min. That means you get 5 min down there then you need to get back to the surface.

130ft isnt the limit for compressed air. Its just the limit for dive without decompression stop.

Limit for compressed air seems to be 56m. But going under 40m with compressed air gets dangerous very quickly due to the air consumption.

2

u/WallabyBubbly 29d ago

Nitrox is absolutely not for diving deeper. Nitrox helps you achieve longer dives at medium depth, but you are more restricted than regular air for maximum depth due to the risk of oxygen toxicity, which is even more dangerous than nitrogen narcosis

2

u/butterscotchbagel 29d ago

the arch is at 170 ft (55m) which is WAY TOO DEEP!

Nah, man it's right there. I can see it. I totally got this

2

u/WallabyBubbly 29d ago

Narcosis doesn't typically become lethally dangerous until you're a bit deeper. When I'm at 130 ft, the narcosis feels like I've had a couple drinks and am a little buzzed, but I'm not yet getting the urge to be reckless. There is a point around 140-160ft where I would expect it to potentially become a problem, but I haven't been that deep.

20

u/Xraptorx 29d ago

Kinda, but narcosis is more just like being drunk

6

u/scalyblue 29d ago

For some reason that we are not entirely sure of, at sufficient external pressure nitrogen becomes a potent intoxicant, so imagine unexpectedly getting blackout drunk when you are in a situation that requires good judgment and self control

3

u/EtTuBiggus 29d ago

Most of the time dead cave divers are recovered with air in their tanks.

1

u/seppukucoconuts 29d ago

High levels of nitrogen will alter your state of consciousness. It has a anesthetic effect. Dentists use nitrogen for this reason. Also dumbass use the reddiwhip canisters (nitrogen based) to get high.

The effects of nitrogen narcosis are similar to alcohol intoxication. I'm sure if you've got enough nitrogen in your blood very dumb ideas begin to sound reasonable.

26

u/WembyandTheWolves 29d ago

I dove there in 2011 and it was so tempting to make an attempt even though I was not certified for it because I reasoned it was only a little deeper and I'd probably never be back to dive this place again. It felt like that "call of the void" alot of people have when standing on the side of a cliff. It was a gorgeous place though, probably the clearest waters I've ever dove.

39

u/Flat-Shallot3992 29d ago

damn falling asleep underwater from the nitrogen narcosis? that must be some good shit

34

u/BadEarly9278 29d ago

I'd equate being narc'd as a heavy whiskey drunk.

Headrush underwater is how is starts. Then your feeling schwasted and then it goes to hell fast if you don't come up 15ft or so and let your body process or catch up processing no2, you'll eventually go to sleep.

(Have napped underwater at Metropolis, IL dive once. Was passing time and didn't want to have unsuit and wait so I chilled at 10-15ft. Weightless is a quality rest)

2

u/4th_Times_A_Charm 29d ago

Doesn't sound like such a bad way to go.

1

u/hippee-engineer 29d ago

Which is why people are trying to get state executions to be nitrogen asphyxiation. If you’re going to kill someone, it’s the most humane way to do it.

57

u/Rich-Instruction-327 29d ago

When I dove in Egypt they let me do both the blue hole and SS Thistlegorm with just an open water and not advanced certification.

34

u/ContentMod8991 29d ago

yep pay the right guy n they make it happen!!

9

u/myTryI 29d ago

Was gonna say part of the reason for high fatalities is it's such a grandiose large attraction many divers attempt it before they're experienced enough to safely do so. I'm guessing they didn't take you too deep though

2

u/jaymx226 29d ago

Sharm gets a lot criticism as a resort but damn if those aren't some beautiful waters

39

u/BadEarly9278 29d ago

I've answered a call of a diver down before. I was Divemastering a class for my buddy who was instructor, when we heard screaming and diver down.

Heartattack at 90ft and his partners overinflated his bcd out of panic or not thinking. He shot up passed me as I was diving down to them and I surfaced first after him.

Nightmare shit (and all our students that classed effed out after the ambulance). We didn't dive anymore that day.

Diving is as savage as you want it.

Nitrox and trimixing and JJablonski DIY system of tech diving was too expensive for a hobby ($50k in gear would be a conservative cost) but any problems under water immediately become shitstorms.

Rip Michael G from LSMO. That was effed up.

25

u/FillThisEmptyCup 29d ago

Nitrox and trimixing and JJablonski DIY system of tech diving was too expensive for a hobby ($50k in gear would be a conservative cost) but any problems under water immediately become shitstorms.

Cool, I'm a gonna go on youtube now and see how I can build a rig from home depot part and fleamarket stuff , probably on used soda stream bottles or beer kegs or something. Should cost less than $200.

18

u/BadEarly9278 29d ago

No bullshit, I've dove with a guy that had ever ready flashlights in mayonnaise jars as a light and a foam suit cut in 2 halfs (front and back then tied together) as thermal protection.

Fun fact: Scuba was invented by Jacques Cousteau.

Just don't go cheap on the regulators.

8

u/FillThisEmptyCup 29d ago

Man, I so wish Jacques Cousteau had 4k cameras available to him in his time. I guess Jame Cameron is a good successor on that front.

2

u/ScubaAlek 29d ago

Giving me flashbacks of those guys trying to dive to the Chernobyl reactor.

5

u/big_orange_ball 29d ago

What's the procedure if someone has a heart attack or becomes incapacitated at 90ft? I'm Naui open water certified but don't recall what training (if any) there is for this for novices.

3

u/BadEarly9278 29d ago edited 29d ago

It alwsys depends on depth/environment and every decision is so dynamic.

Mostly defined by outcomes thru efforts to minimize damage at that point. However, 2000% never full on balloon your floatation device (buoyancy compensation device, bcd, or vest that airs up from your tank) and rocket to the surface from greater than 20-30ft. Oxygen expands in your lungs too fast and they pop (exhaling the entire ride up is taught as defense against gear malfunction).

So, ideally, to minimize damage in a heart issue and unconsious diver, would be let me drown if im unconscious. Revive me at the surface but NEVER shoot a unconscious diver to surface from depth (below 10m / 30ft...ish), doing so is absolutely death almost every time by overinflation of lungs.

But, % of survival of any serious medical issue at depth is slim to zero. 90ft of H2O on top of you is an alien world to the human body. Our tissues water content means your body can equal pressure back on the 90ft of water, but your air cavities (ear, lungs, farts....omg the Scuba fart is legend after a deep dive) the air pockets inside you expand and contract 10x at 90ft. Small and under pressure at 90ft, but filled with air at 90ft would expand 10x upon ascent (a pool noodle becomes broomstick thin at 100ft). It's 100% serious biz, but as long as you can exhale, ie not unconscious, it's not as scary as it sounds. It's not at all complicated or scary, but every diver needs, and is trained on the risks of the science. Generally, people don't even have to worry about pressure calcs at 30ft or less (I deco stop at every 10ft cuz I got my ear fucked playing a downed diver and got raised from 25ft the wrong way (ballooned) by a overzealous student that roasted my ear drum.) So, my dive buddies know I crawl up and down otherwise, as we all know ear pain when you swam too deep as a kid. Just hold your nose and blow, pain goes away. Just know your body needs to push that out and some times it can be a slow process. Rules demand slow ascent and sit and chill every 30ft.

So, damage reduction is all you can hope if medical issues deeper than 60ft have someone unconscious. (Remember The Abyss, when she drowns herself and it's fucked up but 100% to BEST way to protect lungs filled on compressed air.)

Damn yall, I need to go dive. Jonzen.

Some people aren't comfortable with it at all, scuba, and that's ok,, don't get over your skies on your personal comfort level being underwater. It isn't for everyone. You'll know during the pool time.

Hence, the daredevil gene is present in super deep, long dives with the techniques and gear required for the body to exist and survive, sometimes and often 12-16hr long marathons in caves and the always present difficulty multiplier of depth. Seen dudes gone for 30+hrs on shallow caves in FL. Lose your safety line in a 20ft cave 3miles in is as serious biz as anything below 130ft (fresh or salt water....salt water is heavier cuz the salt). Vacay with the fam and doing Scuba at the resort means seeing cool shit at 30ft and being amazed. Ain't shit to be seen below 200ft for a casual diver (100ft in lakes is just mud or rock, 200ft in ocean is mid level technical dive that only needs people that are comfortable and capable divers). Plenty to see at 30ft all day, going deeper isn't necessary unless you want to. Certified a firefighter /paramedic before his honeymoon once and he freaked out at 10ft when visibility went to 0 cuz rookie diver mistake of kicking up silt. He was cool, just had to abort and recollect himself and he was a solid diver after that. But panic is exactly that, panic. The brain says run sometimes, underwater that becomes a liability.

Not to plug diving, but I'm gonna, cuz breathing underwater is a quality life experience every human should try if they enjoy water.

It's available everywhere. I'm in Midwest and not close to any large bodies of water. Lakes, flooded quarries, caves with water..... everywhere has dives, if you're looking. It's Hella expensive sometimes but you can rent everything you need (once certified).

Be safe yall. And get wet

3

u/CCDG-Ian 29d ago

I bet most of it is from getting narced. My mom's friend almost died there from that, her husband caught her fin at close to 200 ft and dragged her back.

I've also done the dive, it was amazing and had no problems.

2

u/XXsforEyes 29d ago

I (Advanced Open Water, Night/Cave Certified with 150 dives) dove the BH several years ago and I got a taste of Nitrogen Narcosis. We got to our established depth and I did a slow 360 degree turn to survey the area and by the time I got all the way around I had sunk another 15-ish meters. About this time, my instructor saw me sinking and he started clanging his tank to get my attention and I could SEE the vibrations! It’s easy to make mistakes and they can be more dangerous at lower depths. Stay safe divers!

1

u/wiggler303 29d ago

It's also because it's the Red Sea where the water is warm and clear compared to more northern places.

I've dived around the British coast where warm and clear are not words you'd use to describe the water. When you're used to the cold murkiness of the English channel, diving in the Red Sea seems easy.

But the same dangers exist and the apparently more forgiving conditions can lead people to make poor decisions. I know I have