Is my approach to diving with Nitrox logical?

[kelemvor]

Those are fine computers though in NA not sure they are available whereas Shearwater is made in Canada and appears to be much smaller, more compact and less money by quite a bit. Deep Six has an interesting computer and Scubapro, well, they are the Pros, hard to go wrong with that magic S on your gear. I will stay with my recommendation as being solid for the price and features and form factor.

For me, I am not interested in anything AI unless it is optional and the screen and features are not compromised with unused space for data I do not want. I look at my spg at the beginning of the dive and to make sure it does not fall when I breath, I look at it again about midway or turn point. I look again at ascent time and then if the DM wants to see the deck pressure yet again. That is it, I do not want my space or mind cluttered with psi, air consumed, average rate of consumption or any of that data which means nothing to me (and I am saying me as in myself). I dive to see things and enjoy the experience, not crunch meaningless to me numbers. My spg is all that I need.

James

They are available in several dive shops in the bay area (Tampa, not the other one). I've got one. Prefer the shearwater. As Americans, we have to dive import computers to get a good one as to my knowledge no domestic company makes anything worth considering. There's definitely opportunity, as I'm sure there's a reasonable number of American divers that would prefer an American computer if it were comparable.

 

[Nemrod]

They are available in several dive shops in the bay area (Tampa, not the other one). I've got one. Prefer the shearwater. As Americans, we have to dive import computers to get a good one as to my knowledge no domestic company makes anything worth considering. There's definitely opportunity, as I'm sure there's a reasonable number of American divers that would prefer an American computer if it were comparable.

You misunderstood me. My statement concerning made in Canada vs somewhere else was not a slap at any foreign or offshore entity. I would be very satisfied with Italy as a source if the product was widely distributed and supported here in North America as is the Canadian made Shearwater. Service and support is a quick call or email away. It was not about being made in Murica or North America, it was about the availability of product, service and support here.

As well, as I indicated, and this is for every diver to decide, I am not enthralled with data rich screens and AI. It is more information than I need and being a Minimalist and really a Hogarthian Minimalist diver, AI does not fit into my universe. Others may vary and that is fine for them but again for me the larger form factor and screen space devoted to all of that data and the four button interface and AI does not suit me. I am looking through my camera VF, all I need to know is how much NDL remaining from my computer and how much air I have left from my SPG, checked twice during the dive. That is all I really want to know.

James

 

[Nitrox_DiverNY]

RGBM does not have GF factor. GFlo is the setting for Deco dives so you can ignore that if you are not doing deco dives. GFhi is for your NDL diving. By the way I am diving with 2 other divers soon for near 3 weeks. I have to be careful that other divers do not simply follow me as my DC is using Bulhman and my GFhi is set at 95. One of the divers I have never met and I do not know what DC he has.
I have had divers not pay attention to their own DC's running RGBM and had them show deco obligation because they did not pay
attention to their NDL settings.

Right now you are overthinking about DCS. Not a bad thing to consider but at shallow depths very unlikely you would ever get bent on NDL dives. My own DC is set for 5 minute safety stops not 3 minutes. It also shows the number of minutes past your safety stop as well.
SO you can see from this log the GF is set at 45 GFlo/95 GFhi. Where I have taken this screen shot is at 27 minutes 30 seconds into the dive. As you can see I still have 4 minutes NDL which is more or less about the time I like to have to no exceed NDL. So on this dive I was staying deep but coming up slowly just to keep the NDL around 4 minutes. So some would say this is pushing the NDL as I only ascend to avoid going into deco. Very shallow at the end for off gassing. A point to note is that a safety stop is not mandatory but recommended.

A Shearwater Peregrine would be a good DC to consider. I am using a Shearwater Perdix but no AI but does have internal digital compass. As one member wrote it is good to get to know your dives and your understanding of your gas usage. I do not gas plan NDL dives as a matter of habit but I do in my head go I will do this dive and expect to end the dive with a certain pressure left in the tank.
Uploading your dive logs and reviewing them can be good fun.


View attachment 733580

thank you for the detailed repose! it is very much appreciated!

 

[DeepSeaExplorer]

I can only say as far back as 2012 when I first got certified, at that time NAUI was using 1.4ppO₂.

It’s been 1.4 for almost 20 years; unfortunately, some of us go back farther than that.

 

[BoltSnap]

NAUI?

IANTD.

I started diving Nitrox in late 80's and was certified by big Dick himself. NAUI sponsored a certification course for instructors circa 90 - 92 in MA and I was among the first 20 NAUI instructors attending that course with big Dick. The max Pp for O2 then was 1.6 but 1.5 was "considered better." This group of NAUI instructors was supposed to be the first group of recreational diving Nitrox instructors in the world. It happened at the Sturbridge Hilton in Sturbridge MA. I vividly remember the hotel opening the bar at 10:00 in the morning just because Dick wanted to have his drink that early. My Nitrox certification card was hand written and signed by the big Dick himself.

At that time NAUI was the only recreational agency in the world that started teaching recreational Nitrox (IANTD was considered a technical diving only at that time). PADI, DEMA, Skin Diver Mag, etc. fought long and hard against the "Devil's gas" (Nitrox). It got to the point where in Grand Cayman if you got bent and needed treatment in a recompression chamber, they advertised that they will refuse treating you. DEMA didn't allow anyone to advertise anything about Nitrox during the DEMA show for a number of years. This attitude continued for several years until PADI saw $$$ in teaching Nitrox and reversed itself and started offering Nitrox courses, I think towards the end of the 90's. The max PpO2 eventually was reduced to 1.4 and became a standard. Was there any real scientific studies on why 1.4 is better vs. 1.5 or 1.6 or was it an arbitrary number that "sounded" safer, I don't know.

P.S. I vaguely remember, but not certain, NASDS has max PpO2 of 1.5 for a while.

 

[tursiops]

Was there any real scientific studies on why 1.4 is better vs. 1.5 or 1.6 or was it an arbitrary number that "sounded" safer, I don't know.

DAN sponsored a workshop in 2000 with a long discussion of the PPO2 limits. Those excerpted pages are attached.

 

[DeepSeaExplorer]

DAN sponsored a workshop in 2000 with a long discussion of the PPO2 limits. Those excerpted pages are attached.

Interesting… Thanks for posting that.

Basically, not a single case of a diver toxing at 1.6. One case of a diver popping pills and another mixed gas diver, but not a single recreational diver.

 

[BoltSnap]

DAN sponsored a workshop in 2000 with a long discussion of the PPO2 limits. Those excerpted pages are attached.

I couldn't find any definitive explanation or justification for the PpO2 1.4 limit for recreational diving in the document you referenced. Did you?

 

[Eric802]

DAN sponsored a workshop in 2000 with a long discussion of the PPO2 limits. Those excerpted pages are attached.

Interesting read!

 

[Eric802]

I couldn't find any definitive explanation or justification for the PpO2 1.4 limit for recreational diving in the document you referenced. Did you?

Richardson: "...PADI had no objection to 1.6 atm. We set it at 1.4 atm for recreational divers as a margin of safety for diver error". I think that's about it; someone else also mentioned that for the most part, you're not giving up much going from 1.6 to 1.4. So it seems to be "Hey, it's safer...why not?"