Air integrated computer and tec diving

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Perhaps I'm mistaken but doesn't the HelO2 just provide the ceiling and ascent time and it's up to you to curve your ascent? I think this is the way all Suunto's (old and new) function on deco. Thus rendering them useless in deco situations.

What is a stop? Isn't it just a rounded depth below the ceiling? Suunto have several deco states - above the floor (off gassing slightly) close to the ceiling (a 3m 'zone') and above the ceiling (beeping and general annoyance for 3 minutes followed by sulking). They also have optional deep stops which tend to be approximately each halving of depth. Those help to control ascent rate, as do annoying beeps. Even if you rush for the ceiling at 9m/min you will end up on a curve, ascending more slowly later in the deco.

In the UK Suunto is the most popular brand of dive computer. British diver training has traditionally included deco diving from the first level. If was only dropped when the first level was split in two parts to compete with PADI. It remains in the second level qualification. The majority of those deco dives will be done on Suunto computers.

---------- Post added January 6th, 2016 at 11:56 PM ----------

Not the tec computers (Vytec, HelO2).


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In my experience of having a helo2 on one wrist and a Zoop on the other the behaviour is similar except for the deep stops, helium and deco gas. Obviously those are serious differences but for simple nitrox deco dives the Zoop etc work just as well.
 
Not the tec computers (Vytec, HelO2).


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I don't think this is correct. Here's what the Vytec manual says:

"Rather than requiring you to make stops at fixed depths, the dive computer lets you to decompress within a range of depths (Con- tinuous Decompression).
The ascent time (ASC TIME) is the minimum amount of time needed to reach the surface in a decompression dive."

Therefore, it's like all other Suunto's. It just gives the ceiling (eg 3m) and ascent time (i.e. TTS) and then its up to you to curve your ascent. Kinda bizarre.

So let's say you're doing a deco dive to 38m for 30 minutes, the Suunto will just display a 3m ceiling while a Petrel will show your first stop at 21m (20/80 GF). Technically, what the Suunto is saying is you can directly ascend to 3 meters and do your entire deco time there. Duh?
 
I don't think this is correct. Here's what the Vytec manual says:

"Rather than requiring you to make stops at fixed depths, the dive computer lets you to decompress within a range of depths (Con- tinuous Decompression).
The ascent time (ASC TIME) is the minimum amount of time needed to reach the surface in a decompression dive."

Therefore, it's like all other Suunto's. It just gives the ceiling (eg 3m) and ascent time (i.e. TTS) and then its up to you to curve your ascent. Kinda bizarre.

So let's say you're doing a deco dive to 38m for 30 minutes, the Suunto will just display a 3m ceiling while a Petrel will show your first stop at 21m (20/80 GF). Technically, what the Suunto is saying is you can directly ascend to 3 meters and do your entire deco time there. Duh?

I have done dives like that. You get an appropriate ceiling. I'd need to start up my laptop and it is midnight here so I am not going to but you could download dm5 and try it for yourself. You can even tell it which model of computer you will dive so it can match the deep stops etc.

Using 20/80 and 'duh?' In the same post may need extra irony emoticons too.
 
What is a stop? Isn't it just a rounded depth below the ceiling?

"below the ceiling" isn't an insignificant factor. How algorithms provide stops below the ceiling (m-value) is just as important as the m-value itself.

Suunto have several deco states - above the floor (off gassing slightly) close to the ceiling (a 3m 'zone') and above the ceiling

If so, perhaps this is why many wouldn't consider it a true technical decompression algorithm.... as they want more control over where they ascend in that pesky range between floor and ceiling...

They also have optional deep stops which tend to be approximately each halving of depth. Those help to control ascent rate, as do annoying beeps. Even if you rush for the ceiling at 9m/min you will end up on a curve, ascending more slowly later in the deco.

I'm confused. Isn't RGBM a bubble/free-phase model? If so, on technical algorithms it should do more than merely add a Pyle stop unilaterally.

This might be why some divers are in doubt of it's validity for deeper diving.... where unilaterally added (Pyle) stops have been shown to increase DCS risk via a poor compromise in slow-tissue on-gassing versus the benefits of fast-tissue/microbubble elimination.

In the UK Suunto is the most popular brand of recreational dive computer
.

Fixed.

British diver training has traditionally included deco diving from the first level. If was only dropped when the first level was split in two parts to compete with PADI. It remains in the second level qualification. The majority of those deco dives will be done on Suunto computers.

It's an unusual scenario, because in the case of BSAC/CMAS, deco diving doesn't necessarily equate to technical diving. BSAC does, however, offer technical diving courses. Are the majority of those conducted with Suunto computers still?

It's been a while since I departed the UK tech diving scene for warmer climes, but in my memory I recall the VR2/3 being very much 'de rigueur' on the technical dive charters.
 
Ok, so the ADP Vision is the most popular brand of technical dive computer then :wink:

VR are now mostly museum pieces.

Indeed deco dive does not equate to the written in blood stuff you were talking about earlier. There is a difference between rock and nitrogen.

The mix of computers is the same regardless of the level of course as far as I can see. The course teaches planning with a PC so the dive computer does not matter. All the students on my mix gas course had Suunto computers. Also on the ADP courses I have been present at, although of course accelerated deco is not technical in Bsac.

When I am in scapa in October I expect I will be the only diver with a 'technical' computer. I expect people will be doing 30 minutes of stops on some of the dives with their suuntos.

With regard to the deep stops vs Pyle and RGBM it seems to me there is some slight of hand going on by Suunto. It does let you ignore them which I think might be a challenge for a true bubble model.

They have got me down and back up numerous times from dives to the limit of my qualification and gas. The plans and execution of those dives is not far off what I'd have done with multi deco and gf computers. Maybe when cold and having drunk too much coffee before hand I might have got out a bit sooner but then maybe I'd just be adding more stress to get a better choice of biscuits.

I am interested in your point about how an algorithm selects a stop below the ceiling. Surely the ceiling is the shallowest depth allowed by the limiting compartment and so the stop just has to be below that? Obviously the particular m value to use depends on the interpolated gf for the depth or whatever m value generation scheme is in place. Other than that it is rounding to a convenient depth and not exceeding the ascent rates. Of course I could easily be missing something.
 
In the UK Suunto is the most popular brand of dive computer.
Pretty appropriate given the cold waters around the UK. Suunto was designed for cold waters.
 
Devon Diver, read your post in response to mine. I'm not offended or put off. I respect your passion. I imagine you're an excellent diver. But as something of a theoretical argument. Aren't all improvements and developments begun as an act of departing from the standard way of doing things?


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*Mods - This RGBM/SUUNTO debate really deserves it's own thread*

When I am in scapa in October I expect I will be the only diver with a 'technical' computer. I expect people will be doing 30 minutes of stops on some of the dives with their suuntos.

That surprises me, based on my UK-located FB friends who tech dive, but I won't dispute it, because I'm not there.

With regard to the deep stops vs Pyle and RGBM it seems to me there is some slight of hand going on by Suunto. It does let you ignore them which I think might be a challenge for a true bubble model.

What you describe sounds like:

"....a traditional Buhlmann table would bring you as close to the surface as possible to get you as close to, but not exceeding, the M-value and keeps you there until you could either move up to the next decompression stop or to the surface without exceeding the M-value". Powell.M Deco for Divers

... but with (optional? ignorable?) Pyle stops added...

That wouldn't make it a Dual-phase model... a true 'bubble' model.

However, RGBM did stem from dual-phase. Wienke was integral to bubble model development (and an advocate of VPM until he wrote RGBM). RGBM is supposed to provide very similar schedules to VPM. But from what you say, the Suunto does not reflect this in practice. That's confusing...

Does this mean that Suunto are dumbing down the model as it is displayed to the diver?

I can understand that for emergency decompression, the recreational diver might be better served by having a simplistic deco schedule... ascend shallow and wait..... but I'd expect no enforced simplicity in a computer that used a dual-phase model specifically for technical divers doing calculated decompression.

I am interested in your point about how an algorithm selects a stop below the ceiling. Surely the ceiling is the shallowest depth allowed by the limiting compartment and so the stop just has to be below that? Obviously the particular m value to use depends on the interpolated gf for the depth or whatever m value generation scheme is in place. Other than that it is rounding to a convenient depth and not exceeding the ascent rates. Of course I could easily be missing something.

This is where, I think, many technical divers prefer the flexibility to influence their schedule. Of course, we're talking about Gradient Factors in relation to hard ceilings. The subtlety is whether an algorithm varies the M-value itself to adjust conservatism, or varies the conservatism below a constant m-value calculation.

On a technical dive, I like to know both factors... I like to know the m-value/ceiling... and I want to know my schedule to come up at a pre-designated point below that m-value. This gives me intelligent options to cope with varied contingencies.

For instance, on Petrel, I like the GF99 display (in addition to my desired GF setting that dictates the ascent). GF99 is my worst case scenario ascent.... when I might have to 'ride the ceiling' for some serious reason or other...




---------- Post added January 7th, 2016 at 09:56 AM ----------

... as something of a theoretical argument. Aren't all improvements and developments begun as an act of departing from the standard way of doing things?

Yes, they are. Technical diving is very pioneering. There's risk in that... trial and error. Errors have severe consequences.

Generally speaking, there are varied principles that apply in both technical and overhead (cave/wreck) diving. Those principles were developed over time... and have stood the test of time. Developments and improvements tend to conform to those principles, even if technology changes. The principles are pretty broad really...

For a development to fly in the face of an accepted principle and be accepted by the community, it'd need considerable testing and debate.

Sidemount is the best current example of this. It doesn't break any of the principles, but it does break protocols. That's caused some division in the tech community. If you've not guessed.... there's always division on the tech community LOL. Small things matter.. Other examples are CCR training... and the development of decompression algorithms (you can see that on this thread also...)

That said, providing the division is based on principles and safety, it's warranted. At no time is it based on "do whatever you please, because who gives a crap? There's no authority...".

Something new gets tried. People argue about it hypothetically. Time proves who is correct in reality. Sometimes tech divers pay a steep price for that. Provided an individual understands the potential risks and consequences, they are free to make an informed decision on what sort of pioneering they want to do.

What doesn't make sense is pioneering in areas that are already known or predictable.

AI technology might prove useful to recreational divers. It's convenient. But recreational divers aren't dealing with multiple cylinders and multiple gasses. They won't die if they misread, or mis-program one of multiple cylinders into their AI computer. They don't have to switch between transmitters as they switch gasses.... adding complexity to a gas switch that'll kill them if they get distracted and mess up. They (probably) won't get bent if they forget to change a gas... and doing so screws up their computer inert gas tracking... or tox because they exceed their CNS/OTUs for the same reasons...

To a recreational diver, AI technology makes things simpler, easier and more convenient. Technical diving is different. The same technology just adds complexity... more steps... more chances for human error.... more chances for electronic failure.

I see this when training novice tech divers - even just with tech computers versus bottom timers. Sometimes task loaded students forget to change their computer gas selection when they do gas switches. Sounds silly, but isn't - given the task loading they face in the early stages of training. Then their computer becomes defunct because it's no longer accurately tracking the gasses they're breathing... potential for bent exists. If they were using slates and bottom timers they'd have nothing to change... no mistake to make... this gas, at this depth, for this time... move up, move onto the next line on the table. Simple... no room for that human error to screw things up.

Will AI and greater digital technology play a greater role in future tech diving... for sure. But, for now, I don't see the capability. AI would have to make technical diving easier, not more complex. To date, it doesn't achieve this benefit (IMHO). The principle of simplicity applies... and it's valid.

As for reliability... my movie playing SS-HDD glitches as often as my old DVD player... which glitched as often as my VHS player did before that.
 
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Perhaps I'm mistaken but doesn't the HelO2 just provide the ceiling and ascent time and it's up to you to curve your ascent? I

However, RGBM did stem from dual-phase. Wienke was integral to bubble model development (and an advocate of VPM until he wrote RGBM). RGBM is supposed to provide very similar schedules to VPM. But from what you say, the Suunto does not reflect this in practice. That's confusing...

When the HelO2 first came out, my buddy (a dive shop owner) got one as a demo and said he wanted to take it along on our dives to see what it would do. For the first day, we planned the dive with V-Planner at +2, using bottom timers only, and he said he played with the options to get it as close to that as he could. On that dive, he made us abandon our V-Planner profile and follow the HelO2 instead. It wanted us to stay deeper longer. We ended up doing more than 15 minutes more deco than we had planned with V-Planner. Everyone else was on the boat when we finally surfaced, and they were pissed. On the second day, my buddy agreed we would just follow the v-Planner schedule no matter what. We followed that plan perfectly, even though the HelO2 did not like it one bit. During the 30 foot stop, the HelO2 finally refused to play any more and went into gauge mode.
 
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