Nitrox...with AIR computer

[Wreck Wench]

MechDiver once bubbled...


That sums it up pretty well. I hardly ever dive air anymore and have yet to buy a nitrox computer. If I want to extend bottom time, I'll use tables.
The only benefit I really see with a nitrox computer is liveaboard diving.

MD

It also depends on the depths....within the 80-120 ft range most people will run out of bottom time before they run out of gas. In these instances it is better to have a nitrox computer which will give you the bottom time margin in addition to the safety margin. If I dove shallow and had access to inexpensive nitrox then I'd dive nitrox as air as well. However most places charge a premium for nitrox and bottom time on air at certain depths is just tooooooooo short!

 

[MechDiver]

Wreck Wench once bubbled...


It also depends on the depths....within the 80-120 ft range most people will run out of bottom time before they run out of gas. In these instances it is better to have a nitrox computer which will give you the bottom time margin in addition to the safety margin. If I dove shallow and had access to inexpensive nitrox then I'd dive nitrox as air as well. However most places charge a premium for nitrox and bottom time on air at certain depths is just tooooooooo short!

As far as depth and nitrox computers, most are so conservative they give you very little bang for the buck. If I wanted to extend my bottom time from 80 to 100 ft or so, I'd use tables; assuming a square profile. Below 100, I'd either go nitrox doubles and deco or mix.

It's easy to get yourself into trouble if you start extending bottom time at the 120' level without having some extended training and upgraded equipment.

I guess I consider nitrox inexpensive, but the cost does vary by region and how its mixed. You bring up good points.

MD

 

[RICHinNC]

Thanks for all the come backs. But, I have to admit I was rather surprised. I thought for sure....although not my intention....the question would cause much fuel for flaming.

I have done a good bit of reading on the subject and couldnt see any reason why using nitrox with an air computer would be a problem. I am not a deep diver. Max is 100...110 and that is rare. Most dives are between 50 and 85 feet .

One thing I would be curious about....but no one seemed to state having such a problem...that being....if you go to rent nitrox tanks are they going to ask to see your computer???.... or just your cert card? And, same question for the boat......will they want to see a computer that does nitrox and flip out if you dont have one?

I dove the Markham off the NC coast line this weekend and would have loved to try nitrox. There were a couple of people there that had it but must have been big breathers because I had better bottom times than any of them. But at the end of both dives I was pretty tired. I am sure the previous few days of hard labor had something to do with contributing to my fatigue...but... I am seriously thinking about going for the nitrox cert.

Cant wait for your answers on the boat and computer question.

 

[MechDiver]

RICHinNC once bubbled...

One thing I would be curious about....but no one seemed to state having such a problem...that being....if you go to rent nitrox tanks are they going to ask to see your computer???.... or just your cert card? And, same question for the boat......will they want to see a computer that does nitrox and flip out if you dont have one?

I dove the Markham off the NC coast line this weekend and would have loved to try nitrox. There were a couple of people there that had it but must have been big breathers because I had better bottom times than any of them. But at the end of both dives I was pretty tired. I am sure the previous few days of hard labor had something to do with contributing to my fatigue...but... I am seriously thinking about going for the nitrox cert.

Cant wait for your answers on the boat and computer question.

A computer is not required for diving, or using nitrox. All you need is a card.

No different on a boat, as most likely not everyone will be using nitrox anyway.

I also would not look at EAN as making your dives stress or work free. Some people think they feel better diving EAN, some can't tell the difference. I can't. If that is the only reason you want to get a nitrox cert, you may be disappointed with the results. I use EAN most all the time because it doesn't cost much, and it may be helpful for rec. dives.

MD

 

[Wreck Wench]

RICHinNC once bubbled...
Thanks for all the come backs. But, I have to admit I was rather surprised. I thought for sure....although not my intention....the question would cause much fuel for flaming.

I have done a good bit of reading on the subject and couldnt see any reason why using nitrox with an air computer would be a problem. I am not a deep diver. Max is 100...110 and that is rare. Most dives are between 50 and 85 feet .

One thing I would be curious about....but no one seemed to state having such a problem...that being....if you go to rent nitrox tanks are they going to ask to see your computer???.... or just your cert card? And, same question for the boat......will they want to see a computer that does nitrox and flip out if you dont have one?

I dove the Markham off the NC coast line this weekend and would have loved to try nitrox. There were a couple of people there that had it but must have been big breathers because I had better bottom times than any of them. But at the end of both dives I was pretty tired. I am sure the previous few days of hard labor had something to do with contributing to my fatigue...but... I am seriously thinking about going for the nitrox cert.

Cant wait for your answers on the boat and computer question.

So what depths did you dive off the Markham? Depending on the depth, your mix (many NC operators use a 30% mix for safety reasons because they aren't sure whether they will dive a wreck that is 60ft or 120ft and they don't want divers to have too rich a mix) and your degree of conservatism i.e. which brand of dive computer you use....you will always extend your bottom time diving nitrox vs. air....however how much will vary based upon the factors mentioned above. As another diver noted....some computers are sooooo conservative you hardly notice the difference diving nitrox over air. However, nitrox as you noted, doesn't help compensate for rapid gas consumption. Regardless of your mix...if you consume a lot of gas then you'll still have a shorter dive as did the guys you mentioned.

As for renting bottles....it has been my experience that all operators will of course ask for your c-card and some will ask if you are diving a nitrox computer. I've seen people tell them they dive nitrox like air and have no problems renting the bottles as long as the mix is right for the depths they plan to dive. I've also seen divers tell them they are diving nitrox tables and as long as they can speak intelligently about them, they have had no problems renting bottles.

I love diving nitrox......yes I feel less taxed after a dive and I love the extended no decompression bottom time I get using it as well as my computer which calculates my multi-level profiles. However when I dive in Florida or Mexico where the diving is shallow...I stick with air and I do just fine.

 

[RICHinNC]

mech... I dont think nitrox is the wonder gas that will solve all problems....but i understand your comment and appreciate it. I have been thinking for a while about doing the training just to expand my knowledge level.

wrench....the markham sits in about 75 to 85 ft of water depending of if you go to the sandy bottom. It is a pretty good dive with lots of life around. This weekend there was this one baracuda that came and hovered with me on the way up. He got within touching distance and just hung there with me. I could see his teeth. Then just as he swam off a my bud on the hang line was pointing like crazy behind me ...and thats not usually a good sign. So I turned realllllllllllll slow and there came a school of 150 to 200 jacks right by me. Average length had to be 2 1/2 foot. A total wall of fish. Man that was cool.

The only bad thing about the Markham dive is it is a rough hour and a half boat ride out. Being a "puker" it is no fun. I cant wait to get there and get under!!

 

[Wristshot]

Rich, one other thing that I did not see posted yet:
In general your bottom times will probably increase a little with Nitrox even if you use an Air computer (or a Nitrox computer with the FO2 set to Air) because with the greater percentage of oxygen in each "bit" you inhale, you actually don't need to inhale as many "bits" in order for your body to get the oxygen that it needs. This is a little like the converse of breathing a little faster when you get to higher elevations when hiking.

Anti-flame Disclaimer: I know that we are all supposed to consistent in our breathing patterns and never alter our breath rate and all that. This is physiology: the "air" you take in from a Nitrox tank has a higher oxygen content so your body doesn't "need" to breathe as rapidly as it would with a lower FO2.

Some people say that Nitrox makes them feel better after a dive, others say they don't feel a difference. There are a lot of factors that affect how tired you feel after a dive. For me and my buddy, climbing that ladder at the end of a dive seemed easier on Nitrox.

Just be more careful about your depth. 'nuff said.

My dos centavos, but only because you asked,

Wristshot

 

[jonnythan]

Wristshot once bubbled...
Rich, one other thing that I did not see posted yet:
In general your bottom times will probably increase a little with Nitrox even if you use an Air computer (or a Nitrox computer with the FO2 set to Air) because with the greater percentage of oxygen in each "bit" you inhale, you actually don't need to inhale as many "bits" in order for your body to get the oxygen that it needs. This is a little like the converse of breathing a little faster when you get to higher elevations when hiking.

Anti-flame Disclaimer: I know that we are all supposed to consistent in our breathing patterns and never alter our breath rate and all that. This is physiology: the "air" you take in from a Nitrox tank has a higher oxygen content so your body doesn't "need" to breathe as rapidly as it would with a lower FO2.

Some people say that Nitrox makes them feel better after a dive, others say they don't feel a difference. There are a lot of factors that affect how tired you feel after a dive. For me and my buddy, climbing that ladder at the end of a dive seemed easier on Nitrox.

Just be more careful about your depth. 'nuff said.

My dos centavos, but only because you asked,

Wristshot

Absolutely wrong.

Breathing response is controlled completely by CO2 partial pressure, not oxygen. At the surface, you breathe more than enough oxygen.. and at only 33 feet you're inhaling twice theo oxygen... but producing the same CO2, which is why your breathing doesn't slow down to half.

So any benefit from decreased SAC due to breathing Nitrox is not due to your body not needing to breathe as quickly to satisfy it's O2 requirements.

 

[Wristshot]

It sounded good when I typed it, but yours sounds better.


Wristshot

 

[sharpenu]

I dive with an Aeris 500AI gas integrated computer. I have gone diving with computers from Suunto, Oceanic and others. Some are more conservative than others, and I have decided to go with the one that gives me a good amount of bottom time without ill effects.

The response by mech diver that said you wont get near the O2 limit is incorrect, as is his statement that nitrox does little to increase bottom time.

He is right that it doesnt help alot on single dives, but you really see the difference in multiple dives. Last year for mini season, I did 6 dives in the 60-65 foot range with EANx36-37 in 24 hours. Without nitrox AND a computer, these profiles would be impossible. I will tell you that at the end of dive 6, my computer showed me maxed on O2 and nitrogen, but it can be done. Try with an air computer or on nitrox tables and see. They were all no deco dives. Here are the profiles:

Mix Depth Time Surface Interval
37 67 51 na
37 62 61 46
36 62 32 57
36 64 41 16 hours
36 65 60 70
36 65 51 62