Would you choose a "Technical." Dive Computer for "Recreational." Diving.

[d^2b]

If I didnt already have a teric and if shearwater came out with a cheaper version of the teric that had just rec diving functionality with AI, I would definitely snap it up. I have no need for multiple gasses or mixes other than nitrox. I dont do deco. And I would be fine with just having 3 or so basic GF options (conservative, etc) rather than an infinite number of choices.

I'm also a purely rec diver, currently diving with a Suunto Zoop Novo, but for reasons looking for a replacement. I would not miss trimix or gas switching, but I do think custom GF is a feature I care about, just because thinking about GF is evolving quickly.

 

[tursiops]

Every atmosphere is like drinking a martini.

This is of the same vintage -- and credibility and utility -- as "ascend with your smallest bubbles."

 

[The Chairman]

This is of the same vintage

Nah, the tiny bubbles theory predates the martini principle by decades. I find it usefulto explain that narcosis isn't an all or nothing thing, but a gradual thing. The deeper I get, the better I feel. At 80fsw, I no longer feel my right shoulder pain.

 

[boulderjohn]

Isn't the idea of helium is that it is an inert gas that can be used to decrease the amount of nitrogen (which does have a penalty) in the mix without increasing oxygen (which also has a penalty)? So, at the very least from a planning perspective you need to be able to say there is less nitrogen and/or oxygen in the mix.

Yes, "from a planning perspective." That means you have to know before a dive what kind of mix you want, and that is part of the trimix training. That happens without a dive computer.

 

[boulderjohn]

But, the determination of "no helium penalty" concluded that there is no helium penalty because dives without helium need to have the extra deco time that helium brings into the plan. So, using a computer that does not support helium to do the kind of dives that require helium would mean that the computer would prompt for less deco than it "should". I.e. less deco than it would if it knew about helium - which the recent research indicates you should do.

Unless there is some computer out there that has had its algorithm and parameters updated to actually reflect the recent research about the helium penalty, I think it would be a serious mistake to use any computer for trimix diving that does not have support for helium.

Correct. That means the algorithm should be adjusted to reflect that new learning, or you should adjust your GFs accordingly.

I actually agree with you completely and almost wrote that into my initial response. If the algorithm is corrected, there is no need to have helium content a part of the computer setup.

 

[HKGuns]

I'm a newer REC diver and bought the Perdix AI, primarily because:

1. I could afford it
2. I find the user interface far more intuitive than a lot of the other options on the market
3. I can easily read the screen
4. Dive log access is really simple an well laid out

I'll use it for Air / EANx dives, but that will be about the extent of the advanced features I will likely ever use.

 

[stuartv]

Correct. That means the algorithm should be adjusted to reflect that new learning, or you should adjust your GFs accordingly.

I actually agree with you completely and almost wrote that into my initial response. If the algorithm is corrected, there is no need to have helium content a part of the computer setup.

I do not think that adjusting GFs is a valid approach to using a computer that does not support helium, for trimix diving. Nor, really, for diving deep air. I mean, it is better than nothing. But, I think the "more likely to keep you unbent" approach is to use a trimix computer for trimix diving, and probably even use a trimix computer for deep air, while setting it for some reasonable mix of trimix, even though you're using air. That way, you will get the extra deco needed, even though you're not actually using helium.

Like I said, I do agree that adjusting to lower GF numbers is better than nothing. But, for me anyway, it would fall into the category of "I'm not diving today because I don't have the right equipment."

Regardless, even if the algorithm gets updated (ZHL-16D? Anyone?), I still think there would be a need to have helium content as part of the computer setup. Record-keeping (via downloaded logs), Isobaric Counter Diffusion alerts, and END alerts all come immediately to mind. I think there are several other considerations, as well. The bottom line to me is I think the computer should always be told exactly what you're breathing - even if the deco calculation doesn't care whether there's helium, or it's all O2 and N2 (but I think it would care, even if the algorithm predicted He and N2 to on- and off-gas identically - different partial pressures of each during the dive would mean different tissue loading of each).

 

[The Chairman]

Hey guys... this is about using a technical computer for rec diving... start another thread about using a rec computer for tech diving. Thanks.

 

[tursiops]

So, is a 40m 10 minute no stop dive on 21/35 technical or recreational?

This is why it is a kind of empty thread.
Just as the dive "type" is ill-defined, the computers one uses are ill-defined.

It is ironic that in a debate about technical vs non-technical (they are both recreational) in which deco itself is ill-defined, and everybody seems to agree that the line between DCS and not is actually a huge gray area, people insist on trying to draw a bright line between technical and non-technical, or technical and recreational, or deep or non-deep.

 

[KenGordon]

Correct. That means the algorithm should be adjusted to reflect that new learning, or you should adjust your GFs accordingly.

I actually agree with you completely and almost wrote that into my initial response. If the algorithm is corrected, there is no need to have helium content a part of the computer setup.

It is quite entertaining to try a few plans in MultiDeco with traditional helium mixes vs air or just no helium. For the 45 to 60m range you might find the helium penalty is negative.

A buddy of mine started out with a couple of Vyper Airs, all was good.