Wanna stay down longgerrr

[MichaelMc]

Would you please post a picture of your computers dive log and graph as I have done from my Perdix. Then we can all be clear what settings your dive computer is on and see the gas used, depth, time, PO2 CNS details as you can see in my dive log. Perhaps even your SAC rate if you have entered the dive tank size and pressure details into something like divinglog.com

Better yet, also, create the dive(s) in Subsurface and post the plot and algorithm parameters.

Creating and plotting in Subsurface and posting the details and plot will get things very concrete and in a setup anyone can replicate so everyone is on the same page. Understanding that your dive computer may have an algorithm that changes things slightly.

Subsurface dive planner and log. Free and opensource and available on Windows, Mac and Linux.
Subsurface | An open source divelog
Download

I agree you should take (or retake) AN/DP. I have no connection with them, but RAID has their class material online. I read through several of their manuals and they are useful.

 

[Angelo Farina]

I'm a recreational diver trained in DECO air dives. So not a technical diver. However over the last few years I have studied about GF factors, CNS, PO2 and other things I never had in training before.

I am in the very same situation as you (apart that, starting with pure-oxygen rebreathers, I had some training on oxygen toxicity, but it revealed to be completely outdated!).
I am learning a lot of "tech" things here on SB, even if probably I do not really need them for my fully-recreational dives, with some occasional deco using my back gas (air)...
I do not plan to use CC rebreathers anymore, so I do not really "need" such info, but it is always useful and pleasant to "know".
I am old, now, so I want to keep everything really simple. And if something requires anything complex, well, it is not for me, not now.
I thank again all the contributors providing such advanced info here.

 

[Alekseolsen]

Oxygen Toxicity Units are usually a system used for technical divers yes? So why would an EANX dive be setup to have OTU shown on a dive computer?

He is claiming he is getting 70% CNS which is near the max limit CNS of 80% yes? As he is not diving on CCR and using O2 at 6m depth how can he have such high CNS or OTU readings if he is diving and not exceeding NDL limits on air or nitrox?

Thats what I wondered as well, and figyred that it would make more sense to incur some 60-70 OUT's between dives than 70% CNS.

I dont think he SHOULD have it visible, just figured that rhis MAY be what is causing confusion

 

[J-Vo]

Well these are the default settings in the Perdix....

These are the current OC tech standards for pretty much all agencies. Note that these settings only change the Shearwater warning levels not the CNS calculation.

 

[J-Vo]

Thats what I wondered as well, and figyred that it would make more sense to incur some 60-70 OUT's between dives than 70% CNS.

I dont think he SHOULD have it visible, just figured that rhis MAY be what is causing confusion

This may be it, if his PDC is reporting OTUs rather than CNS.

 

[tursiops]

He says he has a Mares d.c., but not which model. I believe of all the Mares models that only the Genius displays OTUs.

 

[rx7diver]

Oxygen Toxicity Units are usually a system used for technical divers yes? So why would an EANX dive be setup to have OTU shown on a dive computer?

@BLACKCRUSADER,

Adding to my earlier post (Post #94) in this thread, OTU's are covered in my first nitrox "textbook", Dick Rutkowski's "IAND/IANTD Enriched Air Nitrox Student Manual and Workbook, 2nd Edition." However, my instructor spent very little time discussing this topic--except to mention that OTU's are more useful for hyperbaric oxygen therapy, less useful for recreational OC scuba diving.

My understanding is that Rutkowski spent many years working with Dr. J. Morgan Wells on nitrox at NOAA before he (Rutkowski) retired and began IAND [sic] to offer the first nitrox training to recreational (rather than scientific) scuba divers, c. 1989. Presumably, Rutkowski included in his manual a lot of what was emphasized at NOAA. By the time I took my course (1993), scuba instructors were de-emphasizing OTU's when teaching Nitrox, Advanced Nitrox, Technical Nitrox, etc. All of this is being recalled and/or inferred from ancient memory, so it might not be quite accurate.

rx7diver

 

[Swedinsidemount]

You are asking a different question here than you did before, so you will get a different answer.
Before your issue was CNS buildup, which is NOT really possible given the dives you describe.
If the ONLY issue is getting to 45m "safely" using twin 63s, IF YOU USE AIR the only question is your breathing rate.
Do not try and emulate Black Crusader's dives; he has strange physiology and uses very little gas.
What is YOUR breathing rate?
To go to 45m "safely" you need to account for one of your 63s or the regulator on it failing, because you will need gas to get to the surface and that is in the other 63 you carry. So you need to plan your dive for descending, spending time at 45m, and ascending, all on one 63. . You will find that this is NOT a no-decompression dive...even if you only spend 1 minute on the bottom. So you are talking about a deco dive without enough gas.
You need Deco training, you need to know your breathing rate, you need to do this dive on air, you need to stop worrying about CNS, and after all that you'll find you are probably narced out of your gourd at 45m. Some agencies won't even let you go past 30m without some of the nitrogen in your air being replaced by helium.
You are on a bad path, and staying on it while calling yourself a safe and cautious diver is delusional.

i'm a resonably good breather. And following some of the advice on the manifold thread i got one with twin ports and i'm in the process of finding an identical first stage of the one i already have. I bet i could even put on block switch but for me it already seems pretty safe, oh and yes i do have experience on this setup.... what do you use?thx
<TG>

 

[broncobowsher]

He says he has a Mares d.c., but not which model. I believe of all the Mares models that only the Genius displays OTUs.

That makes the most sense of anything in this thread so far. Looking at OTUs and reading them as CNS. You may have just cracked this thread. And it only took 11 pages.

 

[tursiops]

That makes the most sense of anything in this thread so far. Looking at OTUs and reading them as CNS. You may have just cracked this thread. And it only took 11 pages.

Well, thanks, but it was not my suggestion. In fact, given that the Genius is the only Mares computer that shows OTUs, odds are that he does NOT have a Genius and that as compelling as OYUs as a solution might be, it is unlikely the case. We need to have @Capt. T. Goetz tell us what model Mares computer he has.