Quickest path to deco diving?

[lermontov]

All the helicopter turns and backfinning in the world won't take you out of your comfort zone to make the dive you haven't made before. The whole problem handling an unknown dive is you're not in control and that's what you need to learn to deal with and learn to handle as it happens. Making a dive in a few hours in the Blackwater where I've never dived before and I have no idea what I'll come up against in 6 inches of vis. You can plan and lay lines and set it up as best you can but there's always the unknown. It's the same with any new wreck you don't know till you go there. I'd have to question the experience of someone who thinks there in control all the time.

you haven't realised mac that looking good and having exemplary skills is a new sport -a bit like synchronised swimming. lets face it mac going out there and rubbing you nose in it and getting it done is just old school - and you cant take selfies in 6 inches of vis and post it on social media

 

[Celt]

you haven't realised mac that looking good and having exemplary skills is a new sport -a bit like synchronised swimming. lets face it mac going out there and rubbing you nose in it and getting it done is just old school - and you cant take selfies in 6 inches of vis and post it on social media

Accepted if people wish to do acrobatics in the water and that's their thing that's fine, but telling people they can't make a simple deco dive without being able to do it is just not true. It's not for me as I like getting in the dirt and doing a bit of digging. You may not get the best selfie but you will get results. Photo of a Mexican silver dollar part of a cargo of 2 tons of silver bullion. Mostly gone now but some left if you're willing to get you're nose in the dirt.

 

[Nick_Radov]

for many there is no problem with air at 150. I did AN/DP dives, and several since, on air at 150 with deco of 50 to 100%. Getting narced is a very individual. thing and it is important to understanding your own limits and reactions. For me I have done 150 plus on air with no problems, others get narced at 100. In the end it is about progressive penetration and understanding your limits.

You're delusional. Everyone is susceptible to gas narcosis. But one of the symptoms of narcosis is an inability to objectively assess your own impairment. If you were to perform an objective test of reaction time or logical reasoning on air at 150 ft then I guarantee you would measure significant impairment.

It's not just nitrogen that causes narcosis. Carbon dioxide (CO₂) is actually much worse from a narcosis perspective. For any given level of exertion, CO₂ loading increases with work of breathing, and work of breathing is proportional to gas density. Thus the more helium you have in the mix, the less CO₂ narcosis.

This is of course all covered in Bennett and Elliott. If you guys are getting into tech diving without having understood the basics first then you're aiming for a coffin.

Bennett and Elliotts' Physiology and Medicine of Diving - 5th Edition | Elsevier Shop

Purchase Bennett and Elliotts' Physiology and Medicine of Diving - 5th Edition. Print Book. ISBN 9780702025716

www.elsevier.com

 

[Alaskan Scuba Dude]

But one of the symptoms of narcosis is an inability to objectively assess your own impairment.

That's why you never diver solo at depth.

Carbon dioxide (CO₂) is actually much worse from a narcosis perspective

Most technical divers have some inclination of a CO2 hit and avoid exertion.

For any given level of exertion, CO₂ loading increases with work of breathing, and work of breathing is proportional to gas density.

My lungs are superior to yours.

 

[grantctobin]

That's why you never diver solo at depth.

Most technical divers have some inclination of a CO2 hit and avoid exertion.

My lungs are superior to yours.

Are you certified?

 

[Nick_Radov]

That's why you never diver solo at depth.

Right, I never solo dive regardless of depth.

Most technical divers have some inclination of a CO2 hit and avoid exertion.

Avoiding exertion is a good idea in general, but sometimes **** happens and you need to really crank up the effort to deal with an equipment failure or unexpected current or something. Once the CO₂ level builds up, it takes a while to clear and you're likely to seriously impaired for at least a few minutes at the worst possible time. So, forestall a potential CO₂ hit by using a low-density (i.e. high helium) bottom mix.

My lungs are superior to yours.

That's possible. What are your recent race times like? What is your current VO₂ Max?

 

[Celt]

You're delusional. Everyone is susceptible to gas narcosis. But one of the symptoms of narcosis is an inability to objectively assess your own impairment. If you were to perform an objective test of reaction time or logical reasoning on air at 150 ft then I guarantee you would measure significant impairment.

It's not just nitrogen that causes narcosis. Carbon dioxide (CO₂) is actually much worse from a narcosis perspective. For any given level of exertion, CO₂ loading increases with work of breathing, and work of breathing is proportional to gas density. Thus the more helium you have in the mix, the less CO₂ narcosis.

This is of course all covered in Bennett and Elliott. If you guys are getting into tech diving without having understood the basics first then you're aiming for a coffin.

Bennett and Elliotts' Physiology and Medicine of Diving - 5th Edition | Elsevier Shop

Purchase Bennett and Elliotts' Physiology and Medicine of Diving - 5th Edition. Print Book. ISBN 9780702025716

www.elsevier.com

You only have to worry about your own reaction to narcosis or WOB at depth and how you intend to deal with it, and the only way to find that out is go diving. You can't base it on someone else's experience. Aiming for a coffin is a bit dramatic, no normal person is going to 150 feet without first experiencing shallower depths.

 

[pasley]

I am never going to do cave diving but would like to do some of the very deep wreck dives beyond 130 but less than 180.

Diving on air beyond 130 but not deeper than 180 you say? How many times have we said "just there but no higher" (EE Cummings) or "Just one beer with my old buddies from college" and one becomes two and two becomes, ok someone bought a round, then it is your turn to buy a round so.... Yes, nitrogen narcosis gets more pronounced with depth. So that logical mindset of no deeper may find you deeper, giving in to the siren song of the deep and being more than a little narced.

May I suggest an excellent book that really speaks to this topic as it is mostly about diving deep on air. "A Walk On The Deep Side" by John Kean I found it to be a very good read and covers the history of how diving has evolved regarding diving deep on-air and how relevantly recent the advent of mixed gas diving has come about. Spoiler, it takes place in Sharm el Sheikh Egypt. Enough said.

I too am Somewhat concerned about comments like "Fastest path to" and "I just don't see much of a big deal beyond a comprehension of deco calculations". I would think that Deco Calculations are a big deal and the calculations are just part of it. As I, understand it, you also have to execute the deco plan with precision as to ascent rate, stop times, leaving the stop on time for the next stop, and managing gas consumption and trim.

 

[Wibble]

That's why you never diver solo at depth.

Gosh. Reality is nothing like that.

Every dive is a solo dive whether or not you are diving with others. You are completely responsible for your own safety and must be self sufficient.

 

[Nick_Radov]

You only have to worry about your own reaction to narcosis or WOB at depth and how you intend to deal with it, and the only way to find that out is go diving. You can't base it on someone else's experience. Aiming for a coffin is a bit dramatic, no normal person is going to 150 feet without first experiencing shallower depths.

You only have to worry about your own reaction to booze and how you intend to deal with it, and the only way to find out is to go drunk driving.

Do you realize how stupid that sounds? I prefer to learn from the mistakes of others rather than putting my own life at risk. Just use the correct mix to keep your narcosis and WOB down to a reasonable level. What's so hard about that? It's disappointing to see divers still promoting unsafe practices like deep air in 2022. We had the same discussions on the old Techdiver email list 20+ years ago but I guess some people will never learn. Sad.