ScubaInChicago
Contributor
I believe in the benefits of helium enough that I routinely use 15/55 on 100' dives and shallower without a second thought.
Not diving to greater than 30m/100ft unless with helium
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Eric Sedletzky
Contributor
I remember once spearfishing off the Northern California Coast in about 75 feet of water.
I speared a huge Lingcod and the shot was not a stone kill shot, it went through but didn't slow the fish down. i had one very pissed off lingcod taking me for a wild ride and I had to pull the shooting line in hand over hand amongst the boulders and rocks on the bottom. I finally had hands on the fish and had it pinned on the bottom (practically had to sit on it) and was able to dispatch the fish with a sharp dagger knife. I was breathing hard and little winded from the rodeo and had to recoup for a minute once I had the fish on the stringer.
When I tried to reload my gun, I for the life of me could not remember how to reload my gun which I had shot and reloaded hundreds if not thousands of times. I stared at it and thought it would have to come back to me but it didn't, I just drew a blank, and this was in 75 feet of water...should have been no big deal.
I often wonder if it was narcosis, or now I'm thinking C02 hit
the gas was plain air.
I had dived hundreds of times way beyond that without any trouble, but in this case with all the excitement it really affected me. That was one of those learning moments about working hard , task loading, stress, and the cumulative effects.
I speared a huge Lingcod and the shot was not a stone kill shot, it went through but didn't slow the fish down. i had one very pissed off lingcod taking me for a wild ride and I had to pull the shooting line in hand over hand amongst the boulders and rocks on the bottom. I finally had hands on the fish and had it pinned on the bottom (practically had to sit on it) and was able to dispatch the fish with a sharp dagger knife. I was breathing hard and little winded from the rodeo and had to recoup for a minute once I had the fish on the stringer.
When I tried to reload my gun, I for the life of me could not remember how to reload my gun which I had shot and reloaded hundreds if not thousands of times. I stared at it and thought it would have to come back to me but it didn't, I just drew a blank, and this was in 75 feet of water...should have been no big deal.
I often wonder if it was narcosis, or now I'm thinking C02 hit
the gas was plain air.
I had dived hundreds of times way beyond that without any trouble, but in this case with all the excitement it really affected me. That was one of those learning moments about working hard , task loading, stress, and the cumulative effects.
oldschoolto
Contributor
I , and many other old time divers dove deep on air.. Years before mix gas diving became available to us... Some people can dive air to greater deeps then others.. All divers are not able to work at depth on air.. Fact, like it or not.. Much like the guy that gets stopped at a police check point and looks fine but blows a 2.5 on the alcohol meter... Knowing how to change breathing to clear CO2 is a learned art.. The first thing is understanding what it is... Many divers have no clue... A sad fact of the crappy training rec divers get..
Jim...
Jim...
Eric Sedletzky
Contributor
Because it takes too much time to go over this stuff...time is money.
Besides, how much do they really need to know diving in warm tropical water on a 60' reef holding a divemasters hand?
I learned about CO2 narcosis early on while moving my anchor in deep water. I had a buddy who had been diving deep air for many years tell me to stop, take a couple of long deep breaths and the narcosis would fade. I was amazed the first time I tried it. I wish I had learned that earlier. I wouldn't have aborted so many dives.
Eric Sedletzky
Contributor
I'm just curious, so does C02 loading happen less with other gas mixes besides air?
Is the only reason air is frowned upon is because of narcosis factor?
It sounds like C02 is worse.
is C02 loading less with say 32%?
Or does it matter. Does the body produce the same C02 with equal workload regardless?
Is the only reason air is frowned upon is because of narcosis factor?
It sounds like C02 is worse.
is C02 loading less with say 32%?
Or does it matter. Does the body produce the same C02 with equal workload regardless?
CO2 on air or nitrox is almost the same. But it differs from diver to diver and from dive to dive. It depends on your body (some divers really have CO2 retention, others not), in currents and other hard working circumstances you produce more CO2. CO2 is a gas that is formed by your normal metabolism. Some people produce always more CO2, even in rest, they use more oxygen too. Your RMV does not say if you produce a lot of CO2 or not. It is possible that when 2 divers dive on 50m depth in really calm conditions, both have RMV of 20L/min that 1 of the divers is a CO2 retenioner and the other not. If 2 divers dive in the same conditions and you want to know if your body uses a little bit more than average on oxygen, then let both dive a ccr. A well trained ccr diver uses on average 30-40 bars of oxygen from a 3L cylinder per hour. One of my buddy's uses often without reason 50 bar an hour, I around 25. Using more oxygen for your metabolism means normally more CO2 production.
If you have bad conditions, fighting against currents, cold waters, etc, then you will see your gas consumption on OC is higher. This is because it is like running, you breath faster and your body needs more oxygen. It is not only the breathing rate, but the oxygen your body needs. If you dive ccr you will see your oxygenconsumption grows. Your body produces more CO2.
CO2 is a big molecule. You have to loose your CO2 by breathing out.
When you smoke this goes slower. The more your body produce, the more you have to loose. And it it's then same as with N2, N2 has to pass the lungfilter, CO2 too. So the more efficient is this in your body, the less CO2 retention you have. Best is a low metabolism and a good working lungfilter. Then you loose CO2 most efficient and when going up from depth the N2 too.
Breathing air at depth means the density of the gas grows. And the higher the density the more difficult your regulator gives you gas. And then you can start producing more CO2, or skipbreathing or breathing less efficient and that means your body slows the way of releasing CO2 by your lungs.
Then the narcoses. I never mentioned any narcoses in my dives when I was a sportsdiver. But when I started diving with trimix I knew I have narcoses too. By diving a lot you will learn the symptoms. Teaching an adv. nitrox course does not make really experienced decodivers up to 42m, but they learn the basics and I hope to find a way to let them feel narcoses too. I do that by asking some things at depth. Check your spg and tell me how much gas you have, or take an backuplight and stow it again. You see most times divers are slow with stowing things. Or with telling me the pressure in the cylinders. The last 2 dives of a course are the deepest ones and the deco dives. You can do the dives at 35m, but I try to get to 40-42m (maximum depth of course), because at 35m the narcoses is most times not feelable enough to let people see they have it too.
Teaching the technical diver course means I have to go too to 50+ on air as maximum depth. But with students. I am not more religious than others, so I don't have problems to go to 50m in calm, warm waters with a reef with no difficult circumstances, but not with students. Every diver has narcoses then, me too. Because of experience you can handle the normal skills. Valvedrills, changing masks, checking spg, all that things still can be done with narcoses. Not that my body is used to it, but by experience. But you must realise you are probably slower than normal. When you dive with students, the students are not experienced at these depths, so their reactions are normally always slower than yours because they are not as much experienced as you. But I am slower too due to narcoses. And one of the possible symptoms of narcoses is easier panic. When something happened with a student he is not really experienced in, then narcoses can be a contributing factor to panic. I am slower too in my reactions, so there is a chance you cannot react fast enough to let the stress flow away. So that is why I teach the normoxic trimix course then.
Diving myself on trimix and students on air I do not like. It is the same when teaching an oc course while diving as instructor on ccr.
Helium in your mix makes you breathing easier because the density of the gas is lowered. In CCR diving the EADD can be calculated, the Equivalent Air Density Depth. And helium is not narcotic as N2 is.
Remember: when doing really deep dives, the END can be ok, but the EADD can still be high. I have dived to 132m on ccr with a 6/72 diluent. END (O2 and N2 narcotic) is 33m, the EAD (N2 narcotic) is 28m, and the EADD is 47m. (all calculated for ccr with ccrmixer, oc it is a little bit different as there is no oxygen added to get to a 1.3 setpoint).
You feel at such depths a resistance in breathing. On 1 of these dives to this depth I was breathing 14-16 times a minute. Normally I breathe 6-8 times. There was no reason to work, so it must be CO2, not totally filtered out by the scrubber. It was no cave, just a wall, so I decided to go up and at 110m all was normal again. When it was overhead I am afraid I had to bailout on oc to lower the CO2.
Then another point of narcoses. If you go down fast, the balance between the gas in your body tissues and the gas you are breathing is not balanced. The faster you go down, the bigger is the pressure difference between the PN2 of your gas and the PN2 of your tissues. This is contributing to narcoses too. I had it on a 100m dive on oc. The gas I asked for was 12/60, I got 12/55. END around 45m but I found it acceptable as it was a reefdive, no currents and warm waters. We went down as fast as possible to get the fully 17 minutes of bottomtime. On arrival I was narced, really narced, so narced that I realised you are at 100m depth, you cannot handle an emergency, so go up. I went up to 92m where all was fine again. If you can find the rest to wait a couple of minutes, then the narced feeling gets less (but with END of 45m not totally dissapears). I could not find the rest on this dive. So a next time I will not accept lesser helium than I asked for. On a 50m dive on air I feeled the same, reaching the depth I asked my buddy wait. I was relaxed, did a minute nothing, just laying 2m above the bottom. My buddy recognised me being narced and was just laughing. I still remember that. After 1-2 minutes the feeling dissapeared and we had a normal dive.
Narcoses is really strange, you must know it can be dangerous, and most important you must know the symptoms when it happens to you. Everybody gets it at depth, but at what depth and how serious is unpredictable. 1 time at 43m I fell in love with some stupid rocks. I decided to do the same dive later that day again, went then to 53m and nothing happened. That is the problem. The tunnelvision around 44-46m is typical for me and almost always at that depths. When it comes earlier (yes sometimes it comes) I recognise it. I have never had it shallower than 38m. Falling in love of some stupid stones I had only once.
If you have bad conditions, fighting against currents, cold waters, etc, then you will see your gas consumption on OC is higher. This is because it is like running, you breath faster and your body needs more oxygen. It is not only the breathing rate, but the oxygen your body needs. If you dive ccr you will see your oxygenconsumption grows. Your body produces more CO2.
CO2 is a big molecule. You have to loose your CO2 by breathing out.
When you smoke this goes slower. The more your body produce, the more you have to loose. And it it's then same as with N2, N2 has to pass the lungfilter, CO2 too. So the more efficient is this in your body, the less CO2 retention you have. Best is a low metabolism and a good working lungfilter. Then you loose CO2 most efficient and when going up from depth the N2 too.
Breathing air at depth means the density of the gas grows. And the higher the density the more difficult your regulator gives you gas. And then you can start producing more CO2, or skipbreathing or breathing less efficient and that means your body slows the way of releasing CO2 by your lungs.
Then the narcoses. I never mentioned any narcoses in my dives when I was a sportsdiver. But when I started diving with trimix I knew I have narcoses too. By diving a lot you will learn the symptoms. Teaching an adv. nitrox course does not make really experienced decodivers up to 42m, but they learn the basics and I hope to find a way to let them feel narcoses too. I do that by asking some things at depth. Check your spg and tell me how much gas you have, or take an backuplight and stow it again. You see most times divers are slow with stowing things. Or with telling me the pressure in the cylinders. The last 2 dives of a course are the deepest ones and the deco dives. You can do the dives at 35m, but I try to get to 40-42m (maximum depth of course), because at 35m the narcoses is most times not feelable enough to let people see they have it too.
Teaching the technical diver course means I have to go too to 50+ on air as maximum depth. But with students. I am not more religious than others, so I don't have problems to go to 50m in calm, warm waters with a reef with no difficult circumstances, but not with students. Every diver has narcoses then, me too. Because of experience you can handle the normal skills. Valvedrills, changing masks, checking spg, all that things still can be done with narcoses. Not that my body is used to it, but by experience. But you must realise you are probably slower than normal. When you dive with students, the students are not experienced at these depths, so their reactions are normally always slower than yours because they are not as much experienced as you. But I am slower too due to narcoses. And one of the possible symptoms of narcoses is easier panic. When something happened with a student he is not really experienced in, then narcoses can be a contributing factor to panic. I am slower too in my reactions, so there is a chance you cannot react fast enough to let the stress flow away. So that is why I teach the normoxic trimix course then.
Diving myself on trimix and students on air I do not like. It is the same when teaching an oc course while diving as instructor on ccr.
Helium in your mix makes you breathing easier because the density of the gas is lowered. In CCR diving the EADD can be calculated, the Equivalent Air Density Depth. And helium is not narcotic as N2 is.
Remember: when doing really deep dives, the END can be ok, but the EADD can still be high. I have dived to 132m on ccr with a 6/72 diluent. END (O2 and N2 narcotic) is 33m, the EAD (N2 narcotic) is 28m, and the EADD is 47m. (all calculated for ccr with ccrmixer, oc it is a little bit different as there is no oxygen added to get to a 1.3 setpoint).
You feel at such depths a resistance in breathing. On 1 of these dives to this depth I was breathing 14-16 times a minute. Normally I breathe 6-8 times. There was no reason to work, so it must be CO2, not totally filtered out by the scrubber. It was no cave, just a wall, so I decided to go up and at 110m all was normal again. When it was overhead I am afraid I had to bailout on oc to lower the CO2.
Then another point of narcoses. If you go down fast, the balance between the gas in your body tissues and the gas you are breathing is not balanced. The faster you go down, the bigger is the pressure difference between the PN2 of your gas and the PN2 of your tissues. This is contributing to narcoses too. I had it on a 100m dive on oc. The gas I asked for was 12/60, I got 12/55. END around 45m but I found it acceptable as it was a reefdive, no currents and warm waters. We went down as fast as possible to get the fully 17 minutes of bottomtime. On arrival I was narced, really narced, so narced that I realised you are at 100m depth, you cannot handle an emergency, so go up. I went up to 92m where all was fine again. If you can find the rest to wait a couple of minutes, then the narced feeling gets less (but with END of 45m not totally dissapears). I could not find the rest on this dive. So a next time I will not accept lesser helium than I asked for.
On a 50m dive on air I feeled the same, reaching the depth I asked my buddy wait. I was relaxed, did a minute nothing, just laying 2m above the bottom. My buddy recognised me being narced and was just laughing. I still remember that. After 1-2 minutes the feeling dissapeared and we had a normal dive. Narcoses is really strange, you must know it can be dangerous, and most important you must know the symptoms when it happens to you. Everybody gets it at depth, but at what depth and how serious is unpredictable. 1 time at 43m I fell in love with some stupid rocks. I decided to do the same dive later that day again, went then to 53m and nothing happened. That is the problem. The tunnelvision around 44-46m is typical for me and almost always at that depths. When it comes earlier (yes sometimes it comes) I recognise it. I have never had it shallower than 38m. Falling in love of some stupid stones I had only once.
Randy g
Contributor
Having dove a wreck at 130' back to back with 30% first then ART. I definitely am narced at depth. It was strange to actually "feel" the differences between the two on the dives and to somewhat understand what was going on within myself.
While training, I did puzzles at depth and numerical quiz's to see how much slower I am vs topside and I was actually faster underwater, at depth.
I suppose I function fine with a little buzz on but now understand just how buzzed I really am. If it weren't for the outrageous cost to fill tanks with trimix, I would be diving it on all my 130+ ft dives.
While training, I did puzzles at depth and numerical quiz's to see how much slower I am vs topside and I was actually faster underwater, at depth.
I suppose I function fine with a little buzz on but now understand just how buzzed I really am. If it weren't for the outrageous cost to fill tanks with trimix, I would be diving it on all my 130+ ft dives.
ART is Advanced Recreational Trimix. With IANTD a diver can choose: Adv. nitrox or adv. recreational trimix course. The art course goes to 48m max with END of 24m max and at least 21% oxygen in the mix (24% in course).
Adv. nitrox is to 42m with no helium in the mix.
If a diver wants to do normoxic trimix after adv.nitrox or art I say most times do adv. nitrox and then switch to trimix. YOu will feel the difference. If a diver said I just want to know something about decodiving, inititiation in technical diving, then the art is in my eyes better. A little bit more depth, and the possiblity to dive with helium in the mix.
Adv. nitrox is to 42m with no helium in the mix.
If a diver wants to do normoxic trimix after adv.nitrox or art I say most times do adv. nitrox and then switch to trimix. YOu will feel the difference. If a diver said I just want to know something about decodiving, inititiation in technical diving, then the art is in my eyes better. A little bit more depth, and the possiblity to dive with helium in the mix.
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