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So I will soon be (hopefully) diving the great blue hole in egypt. This has a depth of around 60 meters to get to the arch. Sadly my current camera is rated only to 50 meters.
Who among you would care enough to see me dive the blue hole archway out into the sea enough to make it worth me upgrading my camera?
@freemo
What is the name of this site pls? You'll need nitrox for such a deep dive i guess?
@lefarfadet Nitrox isnt for depth, its doe duration at shallow depths. When you go deep nitrox becomes deadly and you need air, even deeper and air becomes deadly and you actually need a gas with less oxygen than air with some of the nitrogen replaced with helium (hypoxic trimix).
The site is called the blue hole. It is in egypt on the south sinai peninsula just north of dahab.
@freemo
Thanks! i didnt know the nitrox was deadly at depth.
@lefarfadet yea most people wouldnt unless they are a tec diver or nitrox diver. To give you an example 100% O2 is deadly beyond only 20 feet.
O2 toxicity results in seizure so while not directly deadly a seizure under water pretty much is a death sentence.
Your 50m VIRB case would probably work down to 60m, as they usually put in some wiggle room on specs. If it fails, it's not life or death, you just lose a camera. The media (SD card) would probably survive so you could recover what video you had up to that point. Just make sure you record the video into multiple shorter files for easy recovery.
I have a 60m capable older go pro, its just really hard to operate under water due to the pressurized buttons on the case. I'll likely use that.
I have found int he past when you take electronics past their rated depth they do fail, but in a way that is recoverable. The first fail point is usually that the buttons get depressed due to pressure and isnt usable until you come back up enough to alleviate pressure. So you are right it is unlikely to implode by a 10m overshoot.
>they do fail, but in a way that is recoverable.
You wouldn't even be risking the camera then. Maybe there is a way to hack the button depressors, to make them more firm?
The GOPRO should be fine. There aren't many settings on those old GOPROs anyway -- you could just start it on the surface and let it run for the whole dive. I think GOPRO automatically breaks up the video into separate files of 10mins each or something like like that, so if it fails you can easily recover video up to the last segment.
Yea the risk to the camera isnt too bad. Now that I found my gopro and found it is rated to depth im not even worried. That said i never saw a setting to auto split the video and I have had quite a few lost videos before.
>and I have had quite a few lost videos before.
In that case, you better do both!
I cant recall now but I think the GOPRO lost videos more than the VIRB. I do recall much prefering the VIRB for dives in the past.
But yea im thinking on the bluehole I might hire someone to video tape me so I can demonstrate gas changes and other things I cant tape myself and then carrying another camera on me to tape the scenery.
Its a shame I dont have a camera that can go down to 120m. I do dives 120m+ sometime and it would be so cool to tape that but literally everything i have would implode at those depths.
>120m
That's way down there! I think light is an issue at that depth.
The GOPRO is so small you could probably strap it to your arm or forehead or something as a bodycam and just not even think about it.
Depends on where you dive. Even in crystal clear Caribbean waters there is no doubt its a little darker down there and the colors are muted. But there is more than enough light to operate without a flashlight and see in to the distance.
On the flipside if your diving in murky waters like NJ or something it would be pitch dark at that depth.
Anywhere I would care enough to go to 120m+ would be a place that is clear enough I wouldnt need a light. Not including caves of course, need a light for those at any depth.
You could just strap on the camera and forget it, but that tends to result in unusable video. I do often when i cave dibe attach it to my light which itself straps onto your hand in a way you dont need to grip it. That works well since your always pointing the light at the space ahead or whatever you look at.
Yes, I've seen your cave-diving video -- very cool.
I was just trying to think of a way that you could run two cameras simultaneously. If you hire a video guy, I guess you're covered anyway. (Plus you've got an extra tank to buddy breath if something goes wrong.)
As a general rule (and this is contrary to conventional wisdom) I dive every dive as a solo dive even if someone is there. Yes in a pinch a person to help may save your life, but I'd never depend on someone despite the training to do so.
That said all tec divers, but specificially ones like me that are solo-certified, will have reduntant systems on them. Should something fail you always have a backup on you. We wear double tanks with two entierly separate connectors and cutoff valves and a third valve in the middle to isolate the tanks should it be needed. Each tanke then has a completely redundant primary and secondary regulator hooked up to it.
The only thing that isnt redundant is the deco tanks. That worries me personally and probably the only reason having a buddy in an emergency is a must (or at the minimum someone on land to signal to come help).
Well in relity deco tanks and travel tanks.
Typically deco tanks are half tanks (half the size of a single tank). One is 100% O2 the other is 50% O2. You use them during your decompression phase where you surface, which isnt uncommon to take up to an hour. Typically you breath the 50% at a 70 foot stop and the 100% at a 20 foot stop.
The travel tank I just mention is used to get you between the hyperpoxic (>21% o2 oxygen) at 70 feet and the hypopoxic (<21%) gas used at depth.
On a deep dive, which implies a deco dive, we usually have a total of 5 tanks, 2 deco, 1 travel, and 2 tanks as "Back gas" (whats on our back and used at the bottom).
Wow. That's much more complicated than I thought.
No wonder there is so much training involved.
Yea the training for full tec is significant. Soemthing like 20 certs to get there (ball park estimate). Took me 2 years to get to full tec if i compressed it down. Its serious stuff too because if, for example, I took even a single breath off the wrong tank it could cause me to have a seizure.
That said, honestly, its not quite as complicated as it sounds. You get into a routine, check your tanks, breath from the right one, know what to do and practice various failures, and you are good. As long as you dont get distracted and dont let your guard down I find its pretty safe. Almost all real injury came from people rushing and being careless which is all too common.
Plus the brain is so sensitive to breathing and the brain the one thing that's needs to operate well under those conditions.
Indeed and that has a lot to do with how we blend gases. I already mentioned the O2 toxicity at depth that leads to seizure but there are more subtle concerns with other gases. Nitrogen for example in high concentrations and pressure will cause nitrogen narcosis. Feels very similar to being drunk in almost every respect. If you breath air much past about 100 feet or so and it will be so severe you cant function in some cases (depending on depth and sensitivity). Thats why we have trimix gas where a portion of nitrogen is replaced with helium, its mostly just to keep a clear head at depth.
Mountain climbers and pilots face similar issues on the other end, at low pressures, with various limits at certain altitudes.
https://en.wikipedia.org/wiki/Effects_of_high_altitude_on_humans
For sure. In some ways thats worse. At depth you can always reduce one depth or another... At height, on the other hand, you cant ever add more than 100%. You can be at the top of mt Everest breathing 100% O2 and still faint.
Yeah, at some point you need a pressure suit.
Also, at some point in diving you need a suit or vessel to withstanding pressures.
Indeed. though keep in mind the absolute limits can only be reached by the absolutely most fit of people... Someone like me who is far from a fit athlete would probably die at the top of mt everest at 100% o2 where others would survive... even if i was warm and sitting still.
Yeah, fighter pilots need to be really fit, too, for G-forces as well as oxygen/brain function.
for sure.
FYI I was present a few years back on st. Croix when the depth record attempt was made and the diver died. I wasnt involved at all, just present. Very sad of course but I kinda expected it for various reasons.
The deco would have been something like 10+ hours and the deco tanks needed were lined up down the street during filling.
A lot of points of failure. I don't know why people take such risks.
I feel the same way about free diving records. Not worth it.
@Pat I agree personally but respect a persons personal choice to die or risk death as they wish.
Deep diving is tricky because it actually feels way more attainable than it is. That same dive by a commercial diver would actually be no problem. The thing is they would spend days in a chamber decoing rather than try to rush it over the course of 10 hours. Thats the only thing making one impossible and deadly and the other fairly normal.
@Pat Picture of the chamber.
The part on the right is the moon pool they use for getting in and out at depth. The bit on the left usually has chairs and/or a bed along with some other tools which is where they stay for a few days as they decompress.
If you want to look it up it is called saturation diving because you are at such deep depths and for so long that your body tissues become saturated with dissolved pressurized gas.
I'm not a saturation diver, even when i go 120 meters I'm down there a short period to ensure I dont approach saturation.
Attached is an example of a decompression schedule that would be used if you saturated at about 180 meters in the ocean, so a bit farther down than I would ever and have ever went. The time at the top is in days:hours so your looking at 7 days of decompression in a tiny tube for just a few hours or work.
Should give you an idea why an open-circuit record attempt where you decompress over the course of hours instead of days is kinda a death sentence.
Moon pool. I never heard that term, but that's what I was actually thinking. I've seen them in movies, etc. Certainly seems safer than trying to hangout in the water for a day or so, I mean sleep/fatigue itself would be a limiting factor.
yea, though as i stated in my other reply the guys who do commercial diving are at saturation, so its not entierly comparable. A world record attempt is just a touch and go.
Yeah, the commercial divers can rest up in tanks at pressure, but divers in the open water trying to set a record and deco in the water without a moon pool/chamber setup -- I think those guys would be limited by how long they could stay awake during a very long deco in the open water using scuba.
Either limited by how long they stay awake or their risk tolerance. For the guy who died he cut the time too short and his risk tolerance too high. He died and many of us suspected he might. The team that was responsible for him ont he attempt that killed him is actually the same guys that did the earlier portion of my dive training. They arent a bad bunch of people but their risk tolerance was too high and I never quite liked their safety approach when I dove with them which always felt a bit rushed.
To give you an idea at the depths I dive (400ft/120m or so) I can do about 15 minutes bottom time and expect about 2 hours deco, so its manageable... but sitting in one spot in the water for 2 hours can be very boring for many people. Either way at those depths and time it is doable.
Yeah, I think risk tolerance is a personality trait -- caution vs. risk; paranoia vs. complacency. Some people just don't have brains that think a lot about what can go wrong, and they are accident prone as a result.
@freemo @lefarfadet
...they are accident prone as a result...
Then something like COVID-19 comes along and Darwin reigns.
I laughed, then I got sad.
I think there is a big difference between not having brains and simple risk tolerance. You can know all the risks and have a high risk tolerance. You can also be an idiot and do risky things out of ignorance yet have a low risk tolerance.
I would say I have a healthy but relatively high risk tolerance. Afterall I am a deep sea cave diver (among other things) and cave diving is too risky for most deep sea divers, let alone non-divers. I'd say that alone puts me pretty high on the risk-tolerance spectrum.
That said I have an extreme attention to safety measures well beyond your average diver I'd say. So a big part of my own risk tolerance is confidence in my abilities.
When I said, " ...just don't have brains that think a lot about..." I didn't mean they are stupid, I was referring to the way their brains operate, a personality trait not related to intelligence.
Yes, you're right. I think risk tolerance is something different than being accident prone. But then by bring very cautious about the way you approach the risky activity, you reduce the risk.
Ahh ok, well thats fair then.
Yea my caution of course reduces the risk, but the risk is still quite high compared to normal activities. You can dive completely within the rules and still get deco sickness and die. So while i may make the risk more manageable I think its safe to say my tolerance is still higher than most.
@Pat
Sort of. commercial divers have a chamber lowered to them, they get in at depth. it is filled with air. and they are then raised to the surface while the chamber is pressurized to the depth they dove at. Then they stay in the chamber on board the ship for a few days as the pressure is very slowly decreased.
@lefarfadet