DIR, s-drills, consistency, and AI computers

[LiteHedded]

Do you know for a fact that he never looked at it, not even once? Why install the transmitter if they weren't going to use it? Or did they do so to have the data for evaluation later?

I've never argued that AI was necessary, merely that it is convenient to have all data available in one accessible location.

Guy

He does know.

and it was connected to backgas that never gets touched. why would he use it?
as I understand it the project has a relationship with scubapro and tests things like this all the time.

 

[TSandM]

WARNING: THE FOLLOWING IS PERSONAL OPINION and not DIR "doctrine", if there is any on the subject.

You know, I don't think there is anything WRONG with a wrist gauge that shows your backgas pressure. It's sort of marginally useful, but if the transmitter is oriented so it can't impact the roof of the wreck or cave, it's no more of a failure point than the port plug it replaced. If you still have your B&G SPG, you have lost nothing and perhaps gained a little. However, the wrist gauge with the digital display is NOT the way to communicate with your teammates, assuming that you for some reason need to show your pressure to someone else (which GUE-trained divers don't do; this is a UTD thing). That was the OP's original question, and the answer is that there IS something wrong with doing it, because it's harder for the viewer to gain and understand the information you are trying to convey to him. Further, unless you have developed this as a specific procedure unique to your team (which is in violation of the DIR concept of standardization) your teammates will not be expecting to look at your wrist gauge and trying to wrest the information from it.

Any "DIR" answer you get should have solid, cogent reasons behind it. Other than cost, I don't have a good one for why one shouldn't use a transmitter, assuming that one still has the analog SPG. But I have good reasons why one should not show the wrist gauge in the event that your teammates need to know your remaining pressure.

 

[Guy Alcala]

Glanced at? Ya, def. Used to monitor the untouched backgas? Nope. And ya, I do know. The project tests things all the time, and testing an item does not make it DIR.

Having an AI computer along for the dive isn't a big deal and adds little (if and) real risk. The point is that its not needed, and it costs a ton, isn't standard equipment, leads to confusion (the fact that the display info even had to be explained is indicative of this), and is otherwise pointless is why its not DIR.

I will take exception with two points:

First, that the display "leads to confusion." I think what you mean is that THAT display leads to confusion, when all the DIR-types are using analog SPGs with a dial and pointer. That's a matter of acculturation; if we were all used to seeing purely digital displays we'd undoubtedly find reading a pointer on a dial equally confusing at first. And as I pointed out in another post, just because the Galileo displays pressure in digits doesn't mean all computers must do so (the UEMIS uses both methods).

Second, it's not pointless (it's unquestionably more convenient to have all the data on your wrist), it's just not considered sufficiently valuable by the DIR-trained crowd to outweigh the other objections you raise. At least, not yet.

Guy

 

[PfcAJ]

I've got a simple reason. An spg that is not falling as expected is indicative of a left post roll off or closed isolator. Your right post transmitter wouldn't show that.

 

[Sloth]

Guy I think you may be missing a piece of the equation as to why it's safe to say that an AI computer will probably never be considered a foundational piece of "DIR" gear. GUE (and I imagine UTD) trains you from the get go to use your brain as your primary pressure gauge. What does that mean? In a nut shell you are expected to have a rough idea of how much gas you have at any time during a dive.

You mentioned using an AI computer to better calculate your SAC but do you really need an accurate SAC? How granular does your SAC calculation need to be for safe gas planning? I would say its easier to have a SAC range then a nailed down SAC number.

In Hawaii I was diving double 80s on 90% of my dives. I calculated a SAC range for me from .5 to .75. You know what the difference in PSI of a SAC range of .5 and .75 at 100 feet on double 80s is? 20 PSI. So depending on what my SAC rate is for a given dive I am burning between 200 or 300 PSI every 5 mins at 100 feet.

Now for gas planning I take a swag at knowing what my SAC is going to be before the dive. If I was diving all the time I know I would be closer to .5. If I hadnt been in the water for a while I'd plan for .7 SAC. Beautiful thing about using my brain to track my gas is all I have to do is check my pressure gauge every 5 mins until I was confident that I knew where my SAC actually was for that dive. From that point on I wouldnt have to check my PSG because I would be able to pretty painlessly guess within 100 PSI to how much gas I had at that time and at that depth. The next time I would need to check it would be when I knew I was getting close to min gas or if my buddy wanted to know how much gas I had.

I wish I could claim coming up with all this but I'm not really that smart. It was first introduced to me in GUE fundies but being the thick headed person I am it didnt stick. Sadly the light bulb didnt turn on until my Tech 1 class.

The only two pieces of information that is critical to have right in from of you as a "DIR" diver is depth and time. Everything else is just more crap on your gauge. AI computers are really cool, the Gaileo is really cool. If I had the money I might buy one. As cool as an AI computer is, it is from a "DIR" definition a toy.

 

[mikeguerrero]

I own the Galileo Sol and like it for it's very large numbers, I had the VT3 Oceanic before and found the digits too small for my taste.

Since completing Essentials, I've learned more about planning my dive and diving my plan. And what I found or learned is calculating your Rock Bottom, understanding the mininmal gas needed to safely return from a PLANNED depth.

This takes into consideration the tanks being used by all members of the dive. The one feature that I like with my Galileo is the ability to tell the computer to give a simple reminder via alarm when rock bottom has been approached.

Nothing like having a simple addition for alerting me even though I keep and frequent the SPG on the D-ring.

Hey since I have the darn computer, might as well use it, the digits are large and that's why I like it. (JUST MY OPINION TO THE GALILEO SOL).

 

[rjack321]

However, the wrist gauge with the digital display is NOT the way to communicate with your teammates, assuming that you for some reason need to show your pressure to someone else (which GUE-trained divers don't do; this is a UTD thing).

"Don't do" might be a little strong. I am GUE and UTD trained and I occasionally ask my buddies how much gas they have and they ask me sometimes too. Its not a verboten topic UW because sometimes (probably most dives actually) plans change in a fluid manner and its better to be 100% on the same page than make assumptions.

The only reason I have never asked you is because you always have more gas than me anyway.

Hey since I have the darn computer, might as well use it, the digits are large and that's why I like it. (JUST MY OPINION TO THE GALILEO SOL).

Large digits are great as long as the display isn't cluttered with needless numbers. Not AI/SPG related really but I have done ascents sharing a depth gauge and it really is easier to put the diver with the broken gauge on the left of the gauged diver - they can look across and see the depth numbers and there's alot less handwaving.

 

[Guy Alcala]

WARNING: THE FOLLOWING IS PERSONAL OPINION and not DIR "doctrine", if there is any on the subject.

You know, I don't think there is anything WRONG with a wrist gauge that shows your backgas pressure. It's sort of marginally useful, but if the transmitter is oriented so it can't impact the roof of the wreck or cave, it's no more of a failure point than the port plug it replaced. If you still have your B&G SPG, you have lost nothing and perhaps gained a little. However, the wrist gauge with the digital display is NOT the way to communicate with your teammates, assuming that you for some reason need to show your pressure to someone else (which GUE-trained divers don't do; this is a UTD thing). That was the OP's original question, and the answer is that there IS something wrong with doing it, because it's harder for the viewer to gain and understand the information you are trying to convey to him. Further, unless you have developed this as a specific procedure unique to your team (which is in violation of the DIR concept of standardization) your teammates will not be expecting to look at your wrist gauge and trying to wrest the information from it.

Any "DIR" answer you get should have solid, cogent reasons behind it. Other than cost, I don't have a good one for why one shouldn't use a transmitter, assuming that one still has the analog SPG. But I have good reasons why one should not show the wrist gauge in the event that your teammates need to know your remaining pressure.

Lynne, I agree with all the above, but would like to ask you what you think the best display would be? While we're all used to a dial and pointer, I'm thinking that the most intuitive display would be a vertical tank symbol shown full, part full or empty. Appropriate index lines would be present, I'd have a direct digital readout of the exact pressure nearby (probably directly below, as with the UEMIS), and I'd also color code the 'fill'; Reserve capacity would be red (and this should be settable for Rock bottom, thirds or what have you, if not directly computed for depth); 'return gas' would be in yellow or orange, and outbound gas would be in green. All values could be set, or default to a standard. See the right hand part of the UEMIS pressure display, and imagine that larger and in the same colors as the dial display to the left:

http://www.uemis.com/en/products/uemis_zurich/functions/during_the_dive/extras

And it occurs to me that the only reason we use pressure is because a mechanical SPG would have to be a lot more complex to deal with different size and pressure tanks, whereas an electronic SPG could either be set with the appropriate max. pressure and volume manually, or even just read the tank data electronically (say an RFID chip in/on the tank). Naturally, checking that the indicated volume 'makes sense' would be part of your pre-dive inspection (undoubtedly there would be people who'd forget to set it or mis-set it; the RFID chip idea is aimed at them). That way the gauge could give current tank capacity directly, in liters, cu. ft. or what have you, eliminating one level of math.

I imagine you'd need to temperature compensate the reading -- the largest temperature-related pressure drop I've seen between shore and descent was about 200PSI, and I've seen it increase on a few occasions too. Whether using the temperature of the wrist unit would be adequate or you'd need a tank-mounted temperature sensor, I couldn't say.

Of course, since I refuse to rely on any electronic device underwater without at least one backup, I'd need to have a wrist unit and either an electronic SPG on a hose, or else two separate wrist units/transmitters to fully implement this (i.e. same display on both units). Retaining the current mechanical SPG would allow just a single wrist unit and transmitter; only the display would need to be changed to conform to the SPG.

Guy I think you may be missing a piece of the equation as to why it's safe to say that an AI computer will probably never be considered a foundational piece of "DIR" gear. GUE (and I imagine UTD) trains you from the get go to use your brain as your primary pressure gauge. What does that mean? In a nut shell you are expected to have a rough idea of how much gas you have at any time during a dive.

Nope, not missing that at all, indeed I've always dived that way, and always will. And navigated on land and in the air, too, which is why I get so infuriated at people who rely on a GPS but lack basic map and compass skills and don't stay oriented; when the magic box craps out they're SOL. I keep my brain engaged so that I never become dependent on a magic box, but when appropriate I'm perfectly willing to make use of them. How many boat dive sites would be easily accessible now, in almost any surface visibility conditions, if captains had to rely on nothing but visual lineups or dead reckoning to find them, instead of using fathometers, GPS and/or Loran?

You mentioned using an AI computer to better calculate your SAC but do you really need an accurate SAC? How granular does your SAC calculation need to be for safe gas planning? I would say its easier to have a SAC range then a nailed down SAC number.
In Hawaii I was diving double 80s on 90% of my dives. I calculated a SAC range for me from .5 to .75. You know what the difference in PSI of a SAC range of .5 and .75 at 100 feet on double 80s is? 20 PSI. So depending on what my SAC rate is for a given dive I am burning between 200 or 300 PSI every 5 mins at 100 feet.

Now for gas planning I take a swag at knowing what my SAC is going to be before the dive. If I was diving all the time I know I would be closer to .5. If I hadnt been in the water for a while I'd plan for .7 SAC. Beautiful thing about using my brain to track my gas is all I have to do is check my pressure gauge every 5 mins until I was confident that I knew where my SAC actually was for that dive. From that point on I wouldnt have to check my PSG because I would be able to pretty painlessly guess within 100 PSI to how much gas I had at that time and at that depth. The next time I would need to check it would be when I knew I was getting close to min gas or if my buddy wanted to know how much gas I had.

Same basic procedure I follow, but I'm probably a bit more anal about it. Since I do a lot of long range compass nav. dives in limited vis, I record location, pressure, dive time, depth, temp, course and (when I know it) distance at every nav. waypoint on my wrist slate. Since I may do the same dive a number of times (I've got one favorite nav. dive I've done over 30 times), I've got a wealth of data on how my SAC/RMV varies with conditions (current, surge, temp, vis, dry vs. wet, gear, solo or buddied, slow or fast, physical condition, diving recently or not etc.).

Now, that being said, when I plan a dive at an unfamiliar site I make a guesstimate that errs on the conservative side. For example, my regular buddy and I are planning to do a shore dive to a site that requires a descent at about 30 feet, a swim out on bearing and distance of about 1,530 ft. to a depth of 80-85 feet depending on the tide, at least 5 minutes to search for and spend time at the site, and return to our drop point with a 500 PSI reserve, and assuming an average depth of 55 feet: Total dive time minimum of 55 minutes.

I/we've done three practice dives to familiarise ourselves with the bottom features of most of the route and to choose waypoints; we've also dived the site itself from a boat. We've gotten out about 1,100-1,200 feet to around 70 feet in 19-20 minutes on each practice dive.

My initial planning prior to our practice dives assumed enroute RMV of .9 (locally I've seen it anywhere from 0.45 to 1.1 depending on what I was doing), 25 minutes enroute each way, .6 searching/at the site for 5 minutes, all at an average depth of 55 feet. On the three preparation dives, one buddied and two solo, I've had overall RMVs of 0.76 (buddied, average vis, moderate surge), 0.86 (solo, slightly below average vis, very heavy surge, somewhat difficult entry/exit and roughish surface conditions which boosted the stress level), and 0.72 (solo, good vis, moderate surge, easy entry and exit, faster swimming than other two dives; I'd normally expect to see a drop of about 0.10 solo compared to the same dive with a buddy), at average depths right around 40 feet, and that's all spent swimming. So, planning 0.9 gives me some cushion; I've seen RMVs of 0.32-0.54 in local conditions while idling at a site, so 0.6 is also conservative.

I wish I could claim coming up with all this but I'm not really that smart. It was first introduced to me in GUE fundies but being the thick headed person I am it didnt stick. Sadly the light bulb didnt turn on until my Tech 1 class.

Fortunately, I was already used to doing this, having taught map and compass and orienteering as well as doing a lot of navigation in the backcountry (and some flying); there's nothing like having to move cross-country in a blizzard or a whiteout to convince you that failure to keep your head out of your ass, stay oriented and think can quickly lead to you being dead

The only two pieces of information that is critical to have right in from of you as a "DIR" diver is depth and time. Everything else is just more crap on your gauge. AI computers are really cool, the Gaileo is really cool. If I had the money I might buy one. As cool as an AI computer is, it is from a "DIR" definition a toy.

Certainly agree about the two most critical pieces of info, which is why I've always liked the Uwatec Smart Tec display layout: Unless your native language is hebrew, arabic or some other, you've learned to read scanning from left to right before moving down and repeating. Whoever designed Uwatec's display interface arranged the information very well: Most important data on the top line in the biggest fonts, all depth data scannable vertically in the leftmost column, all time data ditto in the rightmost column. The Galileos violate this principle slightly in the Full display, but the supplementary data is clearly that and located outside of the main data area, which does follow the optimal pattern. Now all I have to do is wait until they put out the next generation Galileo (Mars?), which I expect will be color. In five years I imagine it will be difficult to find a computer/BT that isn't.

As to more data being unnecessary or a toy from the DIR perspective, it was only a few decades ago that people were saying the same thing about SPGs -- after alll, _real_ divers knew how much gas they had, J-valves were good enough for them, and they didn't need these new-fangled SPGs that were only for the poorly-trained vacation diver. Harrumph!*
The same thing was also said about single hose regs, redundant second stages (_real_ divers buddy breathe), BCDs (what, you can't control your buoyancy with your lungs?), and ISTR reading that early on in the DIR world dry suits were looked on with horror - why, they're costly, complicated and unnecessary, and introduce multiple failure points with no advantages. Clearly, those weird vintage divers ("Don't worry, he's not that desperate") are the true DIR divers.

So I wouldn't be too sure that Wrist AI will never be DIR.

Guy

*Bret Gilliam describes these types eventually coming 'round, saying that watching them come into the store to buy an SPG was identical to watching a teenager buying condoms at a pharmacy for the first time. You know how it goes, "gimme three of these, 2 of them, 6 of this here and oh, yeah, throw in one of those."

 

[Guy Alcala]

Not AI/SPG related really but I have done ascents sharing a depth gauge and it really is easier to put the diver with the broken gauge on the left of the gauged diver - they can look across and see the depth numbers and there's a lot less handwaving.

Thanks for that; it makes perfect sense and I'm going to file it in my brain's "useful diving tips and tricks to remember" folder.

Guy

 

[Guy Alcala]

I've got a simple reason. An spg that is not falling as expected is indicative of a left post roll off or closed isolator. Your right post transmitter wouldn't show that.

Which is of course why I stated that I would always have a B&G (or at least an hosed or hoseless electronic SPG) on the left side/post, in addition to an AI on the right side/post. Did you think I wouldn't compare them? We members of the Department of Redundancy Department would never countenance such an oversight

Guy