underwasser bolt
Contributor
or we forget about NDL diving and teach decompression techniques, since every dive is basically a decompression dive???? That seems to be where this is going.
Wisdom Computers and new Rule of Halves
- Thread starter FritzCat66
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OP
Yup, that's exactly what it does, and it does calculate the safety stop time as part of the safe time display. That's one reason I got the computer, that's how I use it, and I don't really care what you call gas planning or not. I dive my computer, I stay open water, non-tech, 100' max, I don't do deco, I use the new rule of halves, and I get good dives without DCS. And I always carry a 19 cu.ft. pony with necklaced reg for bailout (which I do NOT count on for extra time, and have never yet needed).
If I started doing tech I would get a different computer, or go old-school with just tables and a bottom timer (maybe ditch my GPS and get a sextant while I'm at it, too); but I think the way I dive is just what computers like the Wisdom are made for, and its ease of use, air-integration, and large clear display are why I bought it. It's been a great computer for me.
Anyway, you guys can bring up your problems with NAUI's new rule on some other board, or go argue with NAUI itself - good luck with that. This is the Sherwood support forum and I'm here to ask Sherwood if they plan to implement the new standard on their computer that I own, not to discuss dive and deco philosophy.
>*< Fritz
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willembad
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Glad you like your computer. You've thought about how it applies to your diving and decided it works for you. I was only stating that you should think the new rule through some possible scenarios.
We all dive computers to get away from the limitations of following square dive decompression theory. All the algorithms in use in dive computers have shown statistically pretty much foolproof. Why not follow the computer if you chose it in the first place? I guess I don't get it. Anyways, you should probably switch to decaf.
Willem
P.S. All my certs are with NAUI. I have no issues with them, but I doubt they are the end all of deco theory.
Willem
We all dive computers to get away from the limitations of following square dive decompression theory. All the algorithms in use in dive computers have shown statistically pretty much foolproof. Why not follow the computer if you chose it in the first place? I guess I don't get it. Anyways, you should probably switch to decaf.
Willem
P.S. All my certs are with NAUI. I have no issues with them, but I doubt they are the end all of deco theory.
Willem
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Charlie99
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IMO, what would make a lot more sense for Sherwood (actually Pelagic) to implement would be either something along the line of Pyle stops or selectable gradient factors.
The NAUI half-depth stop works fine for a square profile dive, but lots of computer divers are doing multilevel dives and for those dives the Naui method is counterproductive. On a square profile dive, the NAUI half-depth stop primarily affects the 5-10 minute compartments, and has little effect on the medium and slow compartments. That's why on multilevel dives I set my ascent stops based upon the last 10 or 15 minutes of my dive before starting the ascent.
A computer can easily look at the average depth for the previous 15 minutes (let's call that the "fast average" and call for a stop halfway between the 20' shallow stop and the fast average. One can either explicitly push a button to tell the computer that you are starting your ascent, or the computer could just always display the depth halfway between the "fast average" and 20'. (Or halfway between the "fast average" and the surface if you want to have the same result as NAUI for a pure square profile dive)
The same way a safety stop time starts when you get to 20', a deep stop timer could start as soon as you hit that deep stop depth. For a perfect square profile the deep stop depth would 10' deeper than the NAUI half depth. For just about any other other, it would be at or a bit shallower than the NAUI half depth.
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My personal preference is actually to make 3 stops. For my normal diving, where even on 130' max depth dive my final ascent starts from no deeper than 100' or 80', my three stops are roughly 40', 30', and then a sliding 20' to 10' shallow stop, with each stop getting longer as you get shallower. This emulates what you get from a true bubble model deco program such as RGBM or VPM is you crank up the conservatism to the point that you start getting mandatory stops at depth. A dive computer could easily be programmed to do such a set of 3 stops, but there has to be some sort of way for the dive computer to either figure out the desired total time of ascent, or for me to tell it how many minutes I choose to take for my stops and ascent.
This sort of multistop profile can also be generated by a dissolved gas model such as used by the Wisdom through the use of gradient factors. By reducing the lo gradient factor enough, one can generate the desired stops, even on a nominally NDL dive.
The trick is to add this sort of feature while not making the computer unduly complicated.
Charlie Allen
The NAUI half-depth stop works fine for a square profile dive, but lots of computer divers are doing multilevel dives and for those dives the Naui method is counterproductive. On a square profile dive, the NAUI half-depth stop primarily affects the 5-10 minute compartments, and has little effect on the medium and slow compartments. That's why on multilevel dives I set my ascent stops based upon the last 10 or 15 minutes of my dive before starting the ascent.
A computer can easily look at the average depth for the previous 15 minutes (let's call that the "fast average" and call for a stop halfway between the 20' shallow stop and the fast average. One can either explicitly push a button to tell the computer that you are starting your ascent, or the computer could just always display the depth halfway between the "fast average" and 20'. (Or halfway between the "fast average" and the surface if you want to have the same result as NAUI for a pure square profile dive)
The same way a safety stop time starts when you get to 20', a deep stop timer could start as soon as you hit that deep stop depth. For a perfect square profile the deep stop depth would 10' deeper than the NAUI half depth. For just about any other other, it would be at or a bit shallower than the NAUI half depth.
-------------------------
My personal preference is actually to make 3 stops. For my normal diving, where even on 130' max depth dive my final ascent starts from no deeper than 100' or 80', my three stops are roughly 40', 30', and then a sliding 20' to 10' shallow stop, with each stop getting longer as you get shallower. This emulates what you get from a true bubble model deco program such as RGBM or VPM is you crank up the conservatism to the point that you start getting mandatory stops at depth. A dive computer could easily be programmed to do such a set of 3 stops, but there has to be some sort of way for the dive computer to either figure out the desired total time of ascent, or for me to tell it how many minutes I choose to take for my stops and ascent.
This sort of multistop profile can also be generated by a dissolved gas model such as used by the Wisdom through the use of gradient factors. By reducing the lo gradient factor enough, one can generate the desired stops, even on a nominally NDL dive.
The trick is to add this sort of feature while not making the computer unduly complicated.
Charlie Allen
I love my Wisdom 2 computer. I like it that I have some control over dive notification limits (warnings) so that the computer can confirm or remind me of things that I should already know, for example, how much gas time I have left, how much NDL time I have left, or how much oxygen loading I have had.
When we dive in known waters, it is easier to create a plan and stick to it, taking into account all the variables mentioned by other posters. However, for many of us who travel to new dive destinations, trying out several new sites a day, the dive plan is usually pretty loose:
In other words, we wing it, relying upon our own and the dive guide's experience to create a profile that minimizes DCS risk.
For example, in Roatan we routinely spent the last 20 minutes of our dives on top of the reefs in 20 ft of water. We didn't have to make defined safety stops because they occurred automatically. Similarly, in Cozumel we often started at 60-80 ft, but then spent the next 40 minutes gradually ascending.
In such cases, defined safety stops at any depth might be overly conservative, and building them into the computer program might be unnecessarily confusing.
One feature that might help us all would be for the computer to let us know (perhaps on screen 2 or 3 in dive mode) what the "average depth" currently is. Right now, the only way I know to get that information is to download the data to my desktop. If I could know my running average depth, I could more easily determine in real time whether I want to make any extra stops.
When we dive in known waters, it is easier to create a plan and stick to it, taking into account all the variables mentioned by other posters. However, for many of us who travel to new dive destinations, trying out several new sites a day, the dive plan is usually pretty loose:
In other words, we wing it, relying upon our own and the dive guide's experience to create a profile that minimizes DCS risk.
For example, in Roatan we routinely spent the last 20 minutes of our dives on top of the reefs in 20 ft of water. We didn't have to make defined safety stops because they occurred automatically. Similarly, in Cozumel we often started at 60-80 ft, but then spent the next 40 minutes gradually ascending.
In such cases, defined safety stops at any depth might be overly conservative, and building them into the computer program might be unnecessarily confusing.
One feature that might help us all would be for the computer to let us know (perhaps on screen 2 or 3 in dive mode) what the "average depth" currently is. Right now, the only way I know to get that information is to download the data to my desktop. If I could know my running average depth, I could more easily determine in real time whether I want to make any extra stops.
OP
Great idea. Maybe we should start a thread here on the Sherwood forum on "Wisdom Improvement Ideas". I think having the average depth on one of the alt displays would be very useful.
Another thing I would definitely add (and I know others have said this before) is a louder alert. Doesn't help to customize the alarms if you can't hear them!
Oh, and clean up that dive log (the PC software)! Several annoying bugs, even on the latest release... like have you noticed that it won't necessarily remember the tank capacity if you key it in after a record has already been saved?
But I do like the Wisdom for the kind of diving I do... I wouldn't be wanting to improve it if I didn't, I would simply be shopping for another dive computer!
>*< Fritz
10-4 on the louder alert needed. Or maybe make the tone last a little longer so that it doesn't get lost in the sound of exhaled bubbles.
And, yes, I have noticed that tank capacity won't always stay put on the desktop version. At first I tried saving before I moved to the next record, but I found that if I move to the next or previous dive without saving, then a message comes up asking me if I want to save. Then when I answer Yes, it seems to work better. Weird sort of bug...
And, yes, I have noticed that tank capacity won't always stay put on the desktop version. At first I tried saving before I moved to the next record, but I found that if I move to the next or previous dive without saving, then a message comes up asking me if I want to save. Then when I answer Yes, it seems to work better. Weird sort of bug...
fisheater
Contributor
I have the same bug and can't hear any of the alarms with a 7 mm hood.
cjbikes
Registered
Guys...guys...
With all due respect to all here, however have we all forgotten what NDL stands for???
I too make a safety stop, either the new 3-1 or a simple 3min at 15 ft.
However...No Decompression Limit...doesn't require us to make any of those stops, they're simply precautionary, so please let's not make this more complex that it really is, all we need now is for some lawyer to get a hold of this and they'll be limiting us to 10 min at 100 ft and requiring dive boat operators to put tanks with regs every 15 ft on the line.
Later,
CJ
With all due respect to all here, however have we all forgotten what NDL stands for???
I too make a safety stop, either the new 3-1 or a simple 3min at 15 ft.
However...No Decompression Limit...doesn't require us to make any of those stops, they're simply precautionary, so please let's not make this more complex that it really is, all we need now is for some lawyer to get a hold of this and they'll be limiting us to 10 min at 100 ft and requiring dive boat operators to put tanks with regs every 15 ft on the line.
Later,
CJ
CJ,
We know that we are talking about optional stops here, but that begs the question of computer options.
The computer also knows that safety stops are optional, and there are no penalties for skipping one. Nevertheless, the Wisdom automatically starts a 3 min safety stop countdown upon ascending to 20ft whether or not you want it to.
We're just wondering whether it would be nice to be able to tell the computer at what depth (or depths) WE want to start a countdown.
We also wish that the computer would tell us "running average depth" -- which may be a more important variable than maximum depth -- so that we can factor that into our decision about whether to make or skip a stop (realizing that the standard conservative recommendation is to make one every time you can).
We know that we are talking about optional stops here, but that begs the question of computer options.
The computer also knows that safety stops are optional, and there are no penalties for skipping one. Nevertheless, the Wisdom automatically starts a 3 min safety stop countdown upon ascending to 20ft whether or not you want it to.
We're just wondering whether it would be nice to be able to tell the computer at what depth (or depths) WE want to start a countdown.
We also wish that the computer would tell us "running average depth" -- which may be a more important variable than maximum depth -- so that we can factor that into our decision about whether to make or skip a stop (realizing that the standard conservative recommendation is to make one every time you can).
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