Another fatal record attempt in Lake Garda, Italy

[Wibble]

Questions about v.deep (say 400m/1300ft) saturation diving...

• One assumes this has been done and the divers returned safely?
• Are all saturation dives done with open circuit?
• Rebreathers are not used in saturation diving?
• Do they collect exhaust gas for recovery/recycling?

I ask as open circuit's just not viable for these extreme depths where the quantity of gas in one breath is incredible -- a SAC of 20 litres/min at 40ATA is 800 litres of gas consumed in one minute -- nearly half an Ali80! Similarly a rebreather will be filtering the same quantity of gas which would probably overwhelm most normal scrubbers, hence the risk of CO2 poisoning.

Just curious!

 

[doctormike]

I mentioned earlier that there was a time when the most highly trained and experienced mountain climbers in the world knew at the beginning of a major ascent that they had a 1/3 chance of dying. I think trying to set a deep dive record is in this category.

I would agree with you if - for example - you had to climb Everest carrying lead weights. And then once you had done it, the next person would try it with an extra pound of weight. And then if that person succeeded, the challenge was to add one more pound. And then just keep doing that, indefinitely.

Look, we have gone around enough with this concept to pretty much hash out the opinions on both sides. I'm not against people attempting difficult things with a high likelihood of death - that's most of our history of exploration. I'm against arbitrary difficulty with no actual end point.

I don't think that anyone answered my question about the record categories for lowest and highest PPO2, or scrubber duration. Why would those record attempts not be admirable? And if it's just depth for depths sake, why not a dry dive in a chamber?

 

[Rollin Bonz]

Holy cow! Check this out. I figured some eating champ probably died of heart disease, but you can actually die while competing: Man Dies During Holiday Hot Dog Eating Contest

I knew it had to have happened. I choked on a hot dog in grade school. Took a bite and the end of the dog shot out of the bun and down my throat. Well not really down, just into. Wouldn't go down, wouldn't come back up. Finally coughed it up on my own, but not before I started seeing spots. 0 out of 10, would not recommend. ALWAYS cut up hot dogs for my kids when they were little. Damn things are the perfect size to plug a throat.

 

[lermontov]

I don't think that anyone answered my question about the record categories for lowest and highest PPO2, or scrubber duration. Why would those record attempts not be admirable?

Right, but the difference is those things are not considered worthy and admirable goals

I think you answered you're own question

 

[doctormike]

I knew it had to have happened. I choked on a hot dog in grade school. Took a bite and the end of the dog shot out of the bun and down my throat. Well not really down, just into. Wouldn't go down, wouldn't come back up. Finally coughed it up on my own, but not before I started seeing spots. 0 out of 10, would not recommend. ALWAYS cut up hot dogs for my kids when they were little. Damn things are the perfect size to plug a throat.

OK, since we all keep going over the same points about depth records, I'll risk an off-topic reply to this with a couple of slides from one of my talks. I'm a pediatric airway surgeon, and I did once see a kid show up dead in the ER after his older sibling gave him a hot dog to eat...

Hot dogs, grapes and balloons. Lethal.

 

[Superlyte27]

A b

The deeper I go, the more I respect how quickly the risks increase and how much it depends upon excellent skills, as in thoroughly practised and automatic. Redundancy--bailout--becomes very difficult the deeper you go, to the extent that extreme dives may choose to not have sufficient bailout, yet it's precisely that which kills people.

Can't speak for others, but I know how long I've been diving and how much I still need to improve. I also know that the deeper you go the longer you need to decompress. That in itself is a limiting factor.

Doing a bounce dive with 12+ hour decompression hang with a very high likelihood of death purely to get a selfie just seems to be a massive ego trip.

A bounce to 225m isn’t 12 hours of deco. You can’t use recreational math to plan these types of dives.

 

[boulderjohn]

A b

A bounce to 225m isn’t 12 hours of deco. You can’t use recreational math to plan these types of dives.

I don't know how to compute the deco on a dive like that, and I also know that few people can. Yet, normal dive planning software will do it for you, even though there is no experimental basis for those results.

A few years ago I was discussing with someone who does decompression work for NASA a fatality on a decompression dive done (attempted, really) at an elevation of 16,000 feet. He said that when you start going to extremes like that, you have to bring into your planning factors that don't have to be considered for the diving we do in the normal world, like the compressibility of water vapor. He said there were only about 6 people in the world who could calculate a decompression dive at 16,000 feet, and he said that the dive that they had planned would have required many hours of decompression.

Yet, if you go to Multideco and choose Buhlmann ZHL-16 C, you will get a plan for such a dive, even though to the best of my knowledge it has never been done by anyone, let alone studied by anyone like Buhlmann. Your deco on that dive plan won't be much different from diving at, say, 8,000 feet.

I certainly would not trust it.

 

[Superlyte27]

I don't know how to compute the deco on a dive like that, and I also know that few people can. Yet, normal dive planning software will do it for you, even though there is no experimental basis for those results.

A few years ago I was discussing with someone who does decompression work for NASA a fatality on a decompression dive done (attempted, really) at an elevation of 16,000 feet. He said that when you start going to extremes like that, you have to bring into your planning factors that don't have to be considered for the diving we do in the normal world, like the compressibility of water vapor. He said there were only about 6 people in the world who could calculate a decompression dive at 16,000 feet, and he said that the dive that they had planned would have required many hours of decompression.

Yet, if you go to Multideco and choose Buhlmann ZHL-16 C, you will get a plan for such a dive, even though to the best of my knowledge it has never been done by anyone, let alone studied by anyone like Buhlmann. Your deco on that dive plan won't be much different from diving at, say, 8,000 feet.

I certainly would not trust it.

I’m not really willing to tell you what I know or how I know it (and I certainly can’t convey a good reason for why I believe it) except that I spent nearly a decade with a guy who spent a few decades at NEDU. We swam in the same circles after he left NEDU (pun intended) and I left commercial dive school. He was an instructor at my school. What I can tell you is that ascent rates and descent rates don’t matter as much as you think at these depths, and MOST software won’t allow you to calculate 300’/min ascents and descents.

 

[Wibble]

A b

A bounce to 225m isn’t 12 hours of deco. You can’t use recreational math to plan these types of dives.

As I said in an earlier post, I threw the numbers at MultiDeco—the only tool I have—and the 300m max came up with around 10 hours. Add a little leeway and there’s another two hours.

TBH whether it is 8 hours or 12 hours is beside the point; it’s a bloody long dive.

 

[Superlyte27]

As I said in an earlier post, I threw the numbers at MultiDeco—the only tool I have—and the 300m max came up with around 10 hours. Add a little leeway and there’s another two hours.

TBH whether it is 8 hours or 12 hours is beside the point; it’s a bloody long dive.

I have other software
And it’s about 6 hours. Still a stupid dive, but I’ve done a 100 8 hour dives and literally thousands of 6 hour dives.