If I recall correctly, hyperventilating is a symptom of hypocapnia, not hypercapnia. That's why people who hyperventilate breathe into a paper bag, so it increases the amount of carbondioxide and slows their breathing rate.
I had a co2 hit on my rebreather once and I can tell you from that experience, yes, it triggers panic, definitely. At least for me. So would agree to you Marc, high probability for gas density. There‘s a video from Simon Mitchell btw where he explains the effects of gas density and why that causes hypercapnia.
#AskMark I want to switch to a long hose primary donate setup and am wondering if it’s common for the backup second stage around your neck to leak bubbles or worse, free flow? My octo that I keep in a plastic bulb regulator holder has a nasty habit of leaking bubbles in my current setup. It does tend to hang with the mouth piece facing up so maybe that’s why I’m having issues and therefore concerned about free flows and I’m sure it wouldn’t hurt to have both regulators calibrated/tuned but figured I’d ask. Thanks Mark, always loved the channel 🙏🏽
Most of the time the AAS around my neck has a dial-a-breath breathing adjustment to prevent it from bubbling. You can still breathe from it but, it's harder to open the valve until you unscrew it. Some 2nd stages can be quite light until you fill them with water. On the surface I gently fill them with water and that tends to prevent them from getting too excited when they're upside-down. Otherwise they could be set up too light and need an adjustment by a service center.
Our TDI ANDP instructor out here in Florida covered gas density complications with CO2 retention and staying below the now fairly widely recognized recommended 5.2g/l limit for gas density. He's also an AP Inspiration trainer, so it's possible this is crossover knowledge from rebreather-territory that he threw in not part of the OC ANDP training. This is the first time hearing it described as 'dark narc' though. Interesting!
I'm pro Nitrox, my twins are O2 cleaned. It does make testing and fills more expensive but, I get the flexibility of filling them with Nitrox if the dive calls for it
#askmark Hi Thanks for all the content I’m trying to find a good base layer Not sure which brand to look at. I’m waiting on a Santi lite suit to come in and have a good under suit. I was hoping to find a lightweight suit that wicks sweat and moisture away Planing on diving year round in uk and Irish waters but if I was abroad and the opportunity to dive was there I would wear it under a wetsuit as well Is there anything suitable or would I need two different types layers. Any suggestions would be greatly appreciated Many thanks K
I wear the Fourth Element J2 a lot. It's thin but, I've been comfortable in all temperatures wearing it underneath my undersuit and it gives you control over your insulation. If you want extra warmth the Xerotherm is a bit thicker for a more thermal base layer for longer or colder dives. BARE are also a great brand to look at, they have some clever technology that goes into their exposure protection. Apeks have a full-body base layer. I haven't tried it yet but, it's nice to see a full-body baselayer. O'Three are also worth looking at, they make great drysuits and undersuits.
Just noticed the Wetsuit part of your question. In that case look at Fourth Element Thermocline, Lavacore and Sharkskin. They are all designed to work when wet as a wetsuit alternative or a wetsuit undersuit. They won't be as effective as a drysuit undersuit as a proper drysuit undersuit. But they will still act as insulation. For year-round protection in the UK though, I would be investing in drysuit undersuit and base layers to stay warm. something like the FE J2 and a Santi BZ400 over the top of that for the colder months.
The exact same thing append to me over 20 years ago. Passed 40m and thought I was going to kill myself. Back above 40m and all was good. Aborted the dive. I put it down to all the reasons one should not dive. Hungover and a lack of sleep do not mix with diving. Learnt a very valuable lesson that day.
#ASKMARK Would an inflator with a forced exhaust button (SAS AACS, TUSA APA) be worth the cost? Of course the Aqualung i3 or Mares air trim looks nice. But it seems to me that exhaust from the dump valve on the right shoulder or the valve that pulls the inflator hose would be sufficient. I would like to know the appeal, as the overhaul price would be about twice as much. I think I would opt for a regular power inflator in the current situation.
I've never seen purging as very much of an issue. I can see some downsides to rapidly venting large amounts of buoyancy and the only time I can see it benefiting a diver is right at the start of the dive and a runaway ascent. Most standard dump valves are fast enough for me so I wouldn't worry about upgrading mine too soon.
And let's not forget the safety benefits of using trimix (Helium) on such dives: Much less narcosis, so you'll actually remember what you saw down there and be able to respond to an incident. Much less deco, i.e. less chance of DCS and shorter hang times. Deep dives on air have a much higher risk profile, so they're discouraged these days.
#askmark Hi Mark, thanks for all your advice - I really appreciate this series. I have a question regarding the Mares first stages. Mares offers these upgrade kits ("twin balanced piston") for certain regulators. They claim to improve the cold water and overall performance. What are your thoughts on these? I am using the 52X first stage and wonder if the upgrade kit would be worth the money.
Yeah, the TBP is a clever solution but, only if you are diving in very cold or contaminated waters. The 52x passed all of the EN250 tests but, if you're diving in sub 10°C regularly then I'd be strongly considering the upgrade to prevent freezing. I have a similar environmental seal kit for one of my 1st stages for diving in cold waters. It just doesn't have the fancy piston inside.
Jesus. If you have to ask why this happened you should probably go seek new training. It might be that their training was literally old. Deep air used to be popular - but is considered *very* non-DIR for this reason (having said that, I just did TDI Extended Range on air myself, lol). Alternatively (perhaps even worse) they weren't properly qualified at all. The effects of nitrogen narcosis are covered in open water courses these days - and repeated over and over in Nitrox courses (at least that's the case with TDI). For me I've had some scares at about 15m and also felt very uneasy at 30m recently... But I also felt a lot more comfortable with depth ever since my first proper deco dive (it was like a light-switch was flicked). We're not actually built to be under water and then you put narcotic effects into the mix and you can unpredictability swing from the warm and fuzzies over to dread and panic because of the complexity of our brains and psychology.
Good points! ❤ But If you’re feeling nervous at 15 to 30m, that’s probably not nitrogen narcosis. It’s most likely too much CO2 (causing rapid breathing) or general nervousness, like maybe you haven’t dived in awhile
One big tip I always tell my students is to * slow down * especially at depth. Breathe full deep breaths, except where needing to adjust breathing for buoyancy. Don’t over-exert. Due to Boyle’s law and gases condensing, if you’re breathing rapidly then CO2 can quickly cause issues like rapid breathing, anxiety, even panic. If you are calm and breathe slowly and deeply, you’re much less likely to run into CO2 issues. Also note: if you’re going that deep, “breathing for buoyancy to navigate over/around an object” likely isn’t an issue as you’re probably on a deep wall, blue hole, or open ocean. So you’ll be able to more closely monitor perfect breathing, and make adjustments with your BCD depending on depth
#askmark My divemaster insists that my hose must be removed from my BCD inflator hose after each dive. I like to leave it on, and just hang everything up together. Why not?
The best reason that I can think of is that it _could_ lead to water inside your regulator. When your LPI hose if fitted to your inflator then the Schrader valve is pushed open. When you remove the LPI hose the Schrader valve closes and will prevent any water ingress. *If* you leave them connected *and* the inflator is submerged *and* you push the inflate button then water can get inside the hose.
I'm wondering if she was breathing the wrong mix, I've seen that done before. It seems odd she has done many dives at that depth and never had that problem before. I've done plenty of dives in the 50/60m range on air and get mild narcosis and nothing more, ever. Or it's just good old narcosis with a bit of hypocapnia. but as I said, why on this occasion. Needs more info, her state of mind before the dive, maybe a medical condition present.etc etc.
Narcosis effects can vary from dive to dive. Depending on whether you're well rested or not, have eaten beforehand or not, etc. Physiological effects are dependent on many factors.
#askmark My wife and I are skydivers at heart, but are both NAUI open water rec divers. Myself being a multi-rated skydive instructor, my scuba dive times are limited as I work in the sport of skydiving every weekend the weather allows. We would love if you could do a video for us skydivers who dive when we can. I always have to be mindful of no flight times after I dive. You hear from divers that “oh you’ll be fine with 8 hours no flight,” or “oh you’ll need 18 hours after diving to go to altitude.” I generally won’t dive 24 hours before I am to make a skydive, but would love some input from you on what the real numbers are. I understand this all deals with depth of dive, time down and such, but a general guideline would be very welcomed. We only go around 60 feet and usually stay down 30 minutes and may do a second dive to 60 for another 30 when we can. Any input would be greatly appreciated! Once again, thanks for the videos as we love watching and learning from you. -Jason & Jessica Collins
The no-fly times have fluctuated over the years and different training agencies have different recommendations which could be a reason for the range of answers you may have heard. It's a very grey area because every diver and dive profile is different so, it's best to err on the side of caution. These are the current DAN recommended no-fly times: 12hr SI for single no-deco dives 18hr SI for multi-day repetitive dives 24+ hours after compulsory deco, or using heliox and trimix Here's an interesting article that includes some studies in the area: dan.org/health-medicine/health-resource/health-safety-guidelines/guidelines-for-flying-after-diving/
Get extereamly narced at 35 to 40 meters on air, especially in dark UK waters. Cant imagine what id be like at 55 on air. Trimix is your friend for these dive especially if a problem needs to be solved
If I recall correctly, hyperventilating is a symptom of hypocapnia, not hypercapnia. That's why people who hyperventilate breathe into a paper bag, so it increases the amount of carbondioxide and slows their breathing rate.
That's correct
Hypercapnia can cause an increase in respiration as the body has excess carbon dioxide wich triggers the need to breath.
It’s a symptom of for both hypo & hyper
@@neilgarrett6271 Not hyperventilation though, the physiological reaction is quite different.
@@ahmedsamy8406 No.
I had a co2 hit on my rebreather once and I can tell you from that experience, yes, it triggers panic, definitely. At least for me. So would agree to you Marc, high probability for gas density. There‘s a video from Simon Mitchell btw where he explains the effects of gas density and why that causes hypercapnia.
#AskMark
I want to switch to a long hose primary donate setup and am wondering if it’s common for the backup second stage around your neck to leak bubbles or worse, free flow?
My octo that I keep in a plastic bulb regulator holder has a nasty habit of leaking bubbles in my current setup. It does tend to hang with the mouth piece facing up so maybe that’s why I’m having issues and therefore concerned about free flows and I’m sure it wouldn’t hurt to have both regulators calibrated/tuned but figured I’d ask.
Thanks Mark, always loved the channel 🙏🏽
Most of the time the AAS around my neck has a dial-a-breath breathing adjustment to prevent it from bubbling. You can still breathe from it but, it's harder to open the valve until you unscrew it.
Some 2nd stages can be quite light until you fill them with water. On the surface I gently fill them with water and that tends to prevent them from getting too excited when they're upside-down. Otherwise they could be set up too light and need an adjustment by a service center.
Great episode Mark! I learned a lot.
Our TDI ANDP instructor out here in Florida covered gas density complications with CO2 retention and staying below the now fairly widely recognized recommended 5.2g/l limit for gas density. He's also an AP Inspiration trainer, so it's possible this is crossover knowledge from rebreather-territory that he threw in not part of the OC ANDP training. This is the first time hearing it described as 'dark narc' though. Interesting!
Another great video. Broke down like a fraction. Hopefully the gentleman is careful moving forward.
Spot on Mark. Trimix should help 👌
#AskMark -
Hi Mark, since you are an avid twinset diver, what’s your opinion on a Nitrox twinset setup?
Cheers
I'm pro Nitrox, my twins are O2 cleaned. It does make testing and fills more expensive but, I get the flexibility of filling them with Nitrox if the dive calls for it
#askmark
Hi
Thanks for all the content
I’m trying to find a good base layer
Not sure which brand to look at.
I’m waiting on a Santi lite suit to come in and have a good under suit.
I was hoping to find a lightweight suit that wicks sweat and moisture away
Planing on diving year round in uk and Irish waters but if I was abroad and the opportunity to dive was there I would wear it under a wetsuit as well
Is there anything suitable or would I need two different types layers.
Any suggestions would be greatly appreciated
Many thanks
K
I wear the Fourth Element J2 a lot. It's thin but, I've been comfortable in all temperatures wearing it underneath my undersuit and it gives you control over your insulation. If you want extra warmth the Xerotherm is a bit thicker for a more thermal base layer for longer or colder dives.
BARE are also a great brand to look at, they have some clever technology that goes into their exposure protection. Apeks have a full-body base layer. I haven't tried it yet but, it's nice to see a full-body baselayer. O'Three are also worth looking at, they make great drysuits and undersuits.
Just noticed the Wetsuit part of your question. In that case look at Fourth Element Thermocline, Lavacore and Sharkskin. They are all designed to work when wet as a wetsuit alternative or a wetsuit undersuit. They won't be as effective as a drysuit undersuit as a proper drysuit undersuit. But they will still act as insulation.
For year-round protection in the UK though, I would be investing in drysuit undersuit and base layers to stay warm. something like the FE J2 and a Santi BZ400 over the top of that for the colder months.
The exact same thing append to me over 20 years ago. Passed 40m and thought I was going to kill myself. Back above 40m and all was good. Aborted the dive. I put it down to all the reasons one should not dive. Hungover and a lack of sleep do not mix with diving. Learnt a very valuable lesson that day.
#ASKMARK Would an inflator with a forced exhaust button (SAS AACS, TUSA APA) be worth the cost? Of course the Aqualung i3 or Mares air trim looks nice. But it seems to me that exhaust from the dump valve on the right shoulder or the valve that pulls the inflator hose would be sufficient.
I would like to know the appeal, as the overhaul price would be about twice as much. I think I would opt for a regular power inflator in the current situation.
I've never seen purging as very much of an issue. I can see some downsides to rapidly venting large amounts of buoyancy and the only time I can see it benefiting a diver is right at the start of the dive and a runaway ascent. Most standard dump valves are fast enough for me so I wouldn't worry about upgrading mine too soon.
@@ScubaDiverMagazine Appriciate! It was my concern for new BCD.
And let's not forget the safety benefits of using trimix (Helium) on such dives: Much less narcosis, so you'll actually remember what you saw down there and be able to respond to an incident. Much less deco, i.e. less chance of DCS and shorter hang times.
Deep dives on air have a much higher risk profile, so they're discouraged these days.
#askmark Hi Mark, thanks for all your advice - I really appreciate this series. I have a question regarding the Mares first stages. Mares offers these upgrade kits ("twin balanced piston") for certain regulators. They claim to improve the cold water and overall performance. What are your thoughts on these? I am using the 52X first stage and wonder if the upgrade kit would be worth the money.
Yeah, the TBP is a clever solution but, only if you are diving in very cold or contaminated waters. The 52x passed all of the EN250 tests but, if you're diving in sub 10°C regularly then I'd be strongly considering the upgrade to prevent freezing.
I have a similar environmental seal kit for one of my 1st stages for diving in cold waters. It just doesn't have the fancy piston inside.
@@ScubaDiverMagazine Thanks, that helps me a lot! :)
Thanks for sharing
Jesus. If you have to ask why this happened you should probably go seek new training.
It might be that their training was literally old. Deep air used to be popular - but is considered *very* non-DIR for this reason (having said that, I just did TDI Extended Range on air myself, lol).
Alternatively (perhaps even worse) they weren't properly qualified at all. The effects of nitrogen narcosis are covered in open water courses these days - and repeated over and over in Nitrox courses (at least that's the case with TDI).
For me I've had some scares at about 15m and also felt very uneasy at 30m recently... But I also felt a lot more comfortable with depth ever since my first proper deco dive (it was like a light-switch was flicked). We're not actually built to be under water and then you put narcotic effects into the mix and you can unpredictability swing from the warm and fuzzies over to dread and panic because of the complexity of our brains and psychology.
Good points! ❤ But If you’re feeling nervous at 15 to 30m, that’s probably not nitrogen narcosis. It’s most likely too much CO2 (causing rapid breathing) or general nervousness, like maybe you haven’t dived in awhile
One big tip I always tell my students is to * slow down * especially at depth. Breathe full deep breaths, except where needing to adjust breathing for buoyancy. Don’t over-exert. Due to Boyle’s law and gases condensing, if you’re breathing rapidly then CO2 can quickly cause issues like rapid breathing, anxiety, even panic. If you are calm and breathe slowly and deeply, you’re much less likely to run into CO2 issues.
Also note: if you’re going that deep, “breathing for buoyancy to navigate over/around an object” likely isn’t an issue as you’re probably on a deep wall, blue hole, or open ocean. So you’ll be able to more closely monitor perfect breathing, and make adjustments with your BCD depending on depth
#askmark My divemaster insists that my hose must be removed from my BCD inflator hose after each dive. I like to leave it on, and just hang everything up together. Why not?
The best reason that I can think of is that it _could_ lead to water inside your regulator. When your LPI hose if fitted to your inflator then the Schrader valve is pushed open. When you remove the LPI hose the Schrader valve closes and will prevent any water ingress.
*If* you leave them connected *and* the inflator is submerged *and* you push the inflate button then water can get inside the hose.
I'm wondering if she was breathing the wrong mix, I've seen that done before. It seems odd she has done many dives at that depth and never had that problem before. I've done plenty of dives in the 50/60m range on air and get mild narcosis and nothing more, ever. Or it's just good old narcosis with a bit of hypocapnia. but as I said, why on this occasion. Needs more info, her state of mind before the dive, maybe a medical condition present.etc etc.
Narcosis effects can vary from dive to dive. Depending on whether you're well rested or not, have eaten beforehand or not, etc. Physiological effects are dependent on many factors.
@@bloodymarvelous4790 Well I've got 3000 dives under my belt, always felt the same to. me.
#askmark My wife and I are skydivers at heart, but are both NAUI open water rec divers. Myself being a multi-rated skydive instructor, my scuba dive times are limited as I work in the sport of skydiving every weekend the weather allows.
We would love if you could do a video for us skydivers who dive when we can. I always have to be mindful of no flight times after I dive. You hear from divers that “oh you’ll be fine with 8 hours no flight,” or “oh you’ll need 18 hours after diving to go to altitude.” I generally won’t dive 24 hours before I am to make a skydive, but would love some input from you on what the real numbers are. I understand this all deals with depth of dive, time down and such, but a general guideline would be very welcomed. We only go around 60 feet and usually stay down 30 minutes and may do a second dive to 60 for another 30 when we can.
Any input would be greatly appreciated! Once again, thanks for the videos as we love watching and learning from you. -Jason & Jessica Collins
The no-fly times have fluctuated over the years and different training agencies have different recommendations which could be a reason for the range of answers you may have heard. It's a very grey area because every diver and dive profile is different so, it's best to err on the side of caution. These are the current DAN recommended no-fly times:
12hr SI for single no-deco dives
18hr SI for multi-day repetitive dives
24+ hours after compulsory deco, or using heliox and trimix
Here's an interesting article that includes some studies in the area:
dan.org/health-medicine/health-resource/health-safety-guidelines/guidelines-for-flying-after-diving/
@@ScubaDiverMagazine thanks! That was a good read!
Get extereamly narced at 35 to 40 meters on air, especially in dark UK waters. Cant imagine what id be like at 55 on air. Trimix is your friend for these dive especially if a problem needs to be solved
Tech and doesn't know about Helium? Doesn't know about nitrogen Narcosis?