Dive Computer Brawl

Greetings all. I am looking to buy a new computer. My Nu-Way tables are getting worn around the edges, and I have to wear reading glasses to see them, which of course floods my mask. (Its hell to get old) I have been looking at the Cochran Commander, and the Dive Rite Nitek. I want to be able to have a dive mix and deco mix. LET THE COMPUTER WARS BEGIN!
Any thoughts??

By the way, I have discarded the advise given to me by the late Capt. Bill Royal in '69. He told me "Just come up till you start to ache, then go back down 20' and wait till it stops". Oh Well, he didn't have Gatorade.

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Originally Posted by OFG-1

Greetings all. I am looking to buy a new computer. My Nu-Way tables are getting worn around the edges, and I have to wear reading glasses to see them, which of course floods my mask. (Its hell to get old) I have been looking at the Cochran Commander, and the Dive Rite Nitek. I want to be able to have a dive mix and deco mix. LET THE COMPUTER WARS BEGIN!
Any thoughts??

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I'd take a look at the Nitek Duo by Dive Rite, it's got a very large, easy to read display, you can set two gasses and it's relatively inexpensive.
If you can afford it, I'd get the Nitek He, that's what I use, it's friggin' awesome and you'll never outgrow it (PO2 alarms, seven gasses etc!!)
Also, if you're able to find a used Nitek 3 for a good price those are nice too, but not as easy to read as the Duo.....Hope this helps :)

Safe diving,

Rich

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Originally Posted by OFG-1

Greetings all. I am looking to buy a new computer. My Nu-Way tables are getting worn around the edges, and I have to wear reading glasses to see them, which of course floods my mask. (Its hell to get old) I have been looking at the Cochran Commander, and the Dive Rite Nitek. I want to be able to have a dive mix and deco mix. LET THE COMPUTER WARS BEGIN!
Any thoughts??

By the way, I have discarded the advise given to me by the late Capt. Bill Royal in '69. He told me "Just come up till you start to ache, then go back down 20' and wait till it stops". Oh Well, he didn't have Gatorade.

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Anyone of the Diver Rite computers would be a great purchase. Plus you can download the data to a computer. They are very affordable.

Remember that the computer screen will be 25 % larger under water.

My experience with Dive Rite has been excellent. DR has been known to replace out of warranty computers on a case by case bases. Not saying that they do it every time. But it's nice to know that thay have a product they stand behind 100%. I won't hesitate to purchase Dive Rite Items.

Plus, I'm a DR Reg tech.

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Originally Posted by OFG-1

I have been looking at the Cochran Commander, and the Dive Rite Nitek. I want to be able to have a dive mix and deco mix. LET THE COMPUTER WARS BEGIN!

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You may want to check eBay for a used Nitek 3. You could probably get one for a good price, and it will allow you to use 3 gasses from air to O2. If you do any trimix diving, you may want to look at the VR3 or Nitek HE. Be sure to ask those that own the HE how their computer deco compares with their tables, though... :roll:

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Originally Posted by Dwain

Remember that the computer screen will be 25 times larger under water.

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Wow....that's pretty impressive....25 times the size, huh? I don't think I like the idea of having to carry a billboard on my arm while diving... :lol:

Mike

I have no personal experience with this particular computer, but I have been hearing good things about the Suunto "Vytek". It is designed to be used as a hoseless air-integrated computer, but can be used as a standard wrist mount computer without buying the hoseless transmitter. It runs RGBM, 3-gasses, and has a good downloader and software (according to my sources). I'm a big DR fan too, but I must admit I'm looking real hard at this one. You might want to investigate it yourself. Oh yeah, and I have seen it list for about half the price of a Nitek He without the hoseless transmitter. Just food for thought, not a recommendation. :wink:

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Originally Posted by MikeH

[ Be sure to ask those that own the HE how their computer deco compares with their tables, though... :roll:
Mike

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Huh? I use tables as a back up, as the HE gets me out way quicker...it also really depends if you're into doing the deeper microbubble stops or not!! If you are, then the VR-3's the way to go but it's expensive....
If using V-planner obviously the tables will be way different since they're based on different algorithms, and the HE will penalize you for the deep stops, but I can mess with decoplanner enough to get it close...
Anyways, I don't really think the original question had anything to do with trimix, everybody has their own opinions on extended deco but I'd recommend the HE to anyone, you'll never "outgrow" it at least on open-circuit :wink:

Safe diving,

Rich

I think the nitek duo is a great computer, it was given a best buy from Rodales senior edition, for being easy to read. and it does two gases.

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Originally Posted by Rich

Huh? I use tables as a back up, as the HE gets me out way quicker...it also really depends if you're into doing the deeper microbubble stops or not!! If you are, then the VR-3's the way to go but it's expensive....

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Try this next time, Rich. Cut your tables and stick to the EXACT dive plan on the tables. Don't put 300' for 20 mins, then spend 2 mins at 300' and 18 mins ascending from 300' to 150' before starting your deco. If you put 300' for 20 mins, spend that long there. Put in realistic descent/ascent rates. I'd be willing to bet your HE will NOT get you out of the water quicker in this case.

Of course, I don't cut backup tables for max depth and run those profiles....I cut them for average depth(20ft intervals, 40ft each way of expected average). I've done quite a few mix dives with my VR3 with somebody else using an HE....and for the same profile...my VR3 always clears much faster. The Nitek series are too conservative. Call DR and ask them what the level of conservativeness is compared to their deco software....I think it's around 50%...I was told once, but don't recall the exact number. Granted, the VR3 has a bit longer runtimes than tables...but on a 250' 25 minute dive, it's usually within 3-5 minutes. The VR3 likes to deco longer at the deeper stops, and shorten the time at the shallower stops...til the 10' stop.

Mike

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Originally Posted by MikeH

I'd be willing to bet your HE will NOT get you out of the water quicker in this case.
Mike

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.....I'd be willing to bet you're right :)

If I run tables off V-planner and use those tables, it'll take ages to get out using the HE because I'll be penalized for the deep stops. However if I forgo the deep stops the HE gets me out usually about 2-3 mins faster than V planner.
I actually use whatever my buddies using...be it tables or the HE. Most of the people I go deep with are using HEs. If they're using a VR-3, I'll use V planner tables so we're somewhat together during deco, and if they're on tables so am I. That's why I back up the HE with decoplanner tables 'cause I can manipulate it.
But don't think I haven't thought about the VR3 :wink:

Safe diving,

Rich

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Originally Posted by OFG-1

and I have to wear reading glasses to see them, which of course floods my mask. (Its hell to get old)

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Try http://www.hs-eng.com

I have one, and the letters are nice and BIG : )

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Originally Posted by MikeH

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Originally Posted by OFG-1

I have been looking at the Cochran Commander, and the Dive Rite Nitek. I want to be able to have a dive mix and deco mix. LET THE COMPUTER WARS BEGIN!

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You may want to check eBay for a used Nitek 3. You could probably get one for a good price, and it will allow you to use 3 gasses from air to O2. If you do any trimix diving, you may want to look at the VR3 or Nitek HE. Be sure to ask those that own the HE how their computer deco compares with their tables, though... :roll:

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I love my Nitek 3. On a typical dive I will add in deeper stops from VPM-B and have never noticed that much of a penalty. Perhaps it would be noticable on much longer or deeper dives, but on 60-90 minute BT dives in JB I do not notice it keeping me down that much longer.

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Originally Posted by MikeH

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Originally Posted by Dwain

Remember that the computer screen will be 25 times larger under water.

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Wow....that's pretty impressive....25 times the size, huh? I don't think I like the idea of having to carry a billboard on my arm while diving... :lol:

Mike

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Just wait, you'll be old one day :roll:

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Originally Posted by DeWayne

I love my Nitek 3. On a typical dive I will add in deeper stops from VPM-B and have never noticed that much of a penalty. Perhaps it would be noticable on much longer or deeper dives, but on 60-90 minute BT dives in JB I do not notice it keeping me down that much longer.

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When I first got my VR3, I ran it side by side with my Nitek 3 for many dives....from 60 minute dives at Telford to 180 minute BT dives at Ginnie, and even a few 180' ocean dives. I never saw the Nitek penalizing me for deep stops on any of the dives under 120'...if it did, it was a negligible amount of time. It did, however, seriously whack me on the deep stops on the 180' dives. The biggest problem was that the Nitek 3 wanted to keep me in the water much longer than the VR3 and my tables(with 0 conservatism). On a 180min BT Ginnie dive, the Nitek wanted to keep me in the water another 45 minutes longer than the VR3(which wanted 80 mins deco). I ended up staying 20 after the VR3 cleared...then hung the Nitek on the end of a jump spool line at the bottom of the eye for another 30 mins...then pulled it out just as it cleared. I had already spent nearly 5 hours in the water....wasn't gonna spend another 30 mins.. :) Aside from that, the Nitek is a great computer...and on the shorter dives, the deco difference was not enough to bug me about doing the extra time.

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Just wait, you'll be old one day :roll:

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I may grow old, but I'll never grow up. Then again, if I get to the point I can't read my computer....I'll just have another laser eye surgery. :lol: They should have something by then that will make me have superhuman vision both near and far, and be able to see everything perfectly in the dark as well(like NVG's with active IR), so I won't even need lights for diving then!

Mike

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Originally Posted by MikeH

I may grow old, but I'll never grow up. Then again, if I get to the point I can't read my computer....I'll just have another laser eye surgery. :lol: They should have something by then that will make me have superhuman vision both near and far, and be able to see everything perfectly in the dark as well(like NVG's with active IR), so I won't even need lights for diving then!

Mike

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LOL, ain't technology wonderful 8)

lol, you go on your buddy's computer, Rich? Not when I had an extra hour of deco using the Suunto... ;)

I've been trying to figure out which computer to go for recently as well. Not sure about the Vytec, but I've got a Suunto Stinger. Okay, it's a single gas computer, but both the Stinger and the Suunto Favour Air Lux (air integrated) suck for anything halfway technical. It doesn't understand deep diving, and adds loads more deco than the Aladdin. And while "conservatism" is a nice concept, it loses its appeal somewhat when you've got half an hour's deco after a 40 minute dive at around 30m/100ft, especially when the water's about 13 degrees C. :-D So for single gas diving, I'd go for the Aladdin, and from what I hear you're best to try to get an older one from eBay. However, I'm looking to use deco gas as well.

I'm going to be back in Florida next month (got about a 3 month window where I can stand the temperatures - it's called "winter") and the first thing I'm expecting to do is get either a Nitek Plus or a Nitek 3. The Plus doesn't look daft when you figure that it'll do in place of a watch, and while I expect to do deco stops, I don't expect to use a travelling gas so really can't see much benefit from having 3 mixes available. Especially when people are saying above that it's harder to read. Personally, I'm not going for an He because I don't think I'll ever use Trimix, and it's too much of an investment to get it if I don't.

There's also an interesting article on diverite.com just now regarding stop lengths on tables vs their computers: http://www.diverite.com/tec_talk/conservatism/index.htm

I second Rich's vote for the Nitek He. It will penalize you for the deep stops, but if you work it right it is not really that bad. The He is very easy to use, has a nice display, is intutive (at least to me), and does not add any task loading underwater. The VR3 is a very nice computer, but to me seems overly complicated (even though a couple of my friends that have them say I am nuts...). The only thing i wish the He did is to keep the backlight LED on longer. When you press the button to fire up the backlight it only stays on for about 3 seconds and then bam....goes off.

A word of caution about the VyTec. It is a Suunto RGBM model, not necessarily the Bruce Wienke RGBM model. It starts deco usually shallower than my He, and generally extends the stops from 20-10 feet for longer. In my experience on a 140 foot dive for around 25 minutes I get a ceiling of less than 20 feet for my first deco stop. The He would be giving me a first stop at 40 feet, and V-Planner would be stopping at 70 or 60 feet. It basically seems to add extra deco for doing stuff that is generally considered bad decompression practice. It also penalizes you a lot for a repetitive dive by having a lot more nitrogen retention that most other computers.


Dive Safe,

Ryan

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Originally Posted by Stu

lol, you go on your buddy's computer, Rich? Not when I had an extra hour of deco using the Suunto... ;)

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Stu!!

What's up you animal, can't wait to see you next month!! Hey, I have an old Nitek3 you can use, and I'll cut you a great deal on the DUO if you'd like.....See ya soon :twisted:

Safe diving,

Rich

P.S. Your pass has an extra month on it now, even more of an excuse to come back again in the spring :-D

Both the Dive Rite Nitek 3 and He are great for air and Nitrox dives with the ability to switch gasses. However, If you plan to use the Nitek He for trimix - Don't! It is far too conservative particularly on the O2 stop. It is worse on deeper Hypoxic mixes. If you plan on diving mix, I would recommend the VR3.

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Originally Posted by jpdiver

. If you plan to use the Nitek He for trimix - Don't! It is far too conservative particularly on the O2 stop.

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You're misinformed, I dive in the 200 - 300' range all the time with mine and it gets me out faster than V-planner. I'm not familiar with the VR3, but they're expensive and when you work for a DR dealer.... :-D
Most of the people I dive deep with on a regular basis use them...anyways just my O2 :D

Safe diving,

Rich

Rich is correct, deep helium dives are very easily done on the He. If you find it too conservative, you are expecting different algorithms to behave in the same manner. Cut tables using Buhlmann and actually dive what you planned and the He will track to the minute.

Jerry

You're misinformed, I dive in the 200 - 300' range all the time with mine and it gets me out faster than V-planner. I'm not familiar with the VR3, but they're expensive and when you work for a DR dealer....
Most of the people I dive deep with on a regular basis use them...anyways just my O2

Safe diving,

Rich


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Not misinformed. I have both a Nitek He and VR3 and have run them both together. The He is more conservative. I understand it becomes more conservative if you insert deep stops but I strongly believe in doing them.
I am not familiar with V-planner tables I use DecoPlanner. The VR3 tracks closely to them just slightly more conservative at the 20' stop. After 2 years of deep mix dives with the VR3 as backup, I now dive it and carry tables as backup.

I agree it is more expensive with a longer learning curve. I also like the Big Graphics mode and ability keep the backlight on during the dive. Easy to read on dark Northeast Wreck dives in bad vis.

"I understand it becomes more conservative if you insert deep stops but I strongly believe in doing them."


...and there you have it! Everybody has different opinions which is as it should be, I just try to be flexible...if my buddy's doing deep stops, I'll do them with him/her and use tables etc, there's not that much difference anyways so long as you know what you're doing :-D

Safe diving,

Rich

Ya know...conservatism ain't a bad thing considering what happens when we ain't conservative enough.... :-D

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Originally Posted by REastman

Ya know...conservatism ain't a bad thing considering what happens when we ain't conservative enough.... :-D

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Of course I might not take advice on dive computers from someone who really thinks "ain't" is a word... :-D

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Originally Posted by REastman

Of course I might not take advice on dive computers from someone who really thinks "ain't" is a word... :-D

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Back where I moved from "ain't it" is considered a whole sentence and/or commentary :D

Safe diving,

Rich

I dive/fly a Nitek 3 and absolutely love it. My girlfriend has the Duo and thinks it is great. For deeper dives I plan everything on tables and software and the computer makes a great reference point. Then again I am not pulling the type of dives that others are around here so my experience is limited to Extended Range. Gee, guess i need to take that class. :roll:

I am hopeful that soon we will see computers that will allow the divers to make a series of selections similar to software to better meet the needs of divers. IE – pick your algorithm, micro bubble, deep stops, and follow the work done by people like the vr3 and Hs Explorer. There is a lot of work left in the field of computers and the high end units are limited in price and who sells them. Well at least I can dream.

Andrew

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Originally Posted by REastman

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Originally Posted by REastman

Ya know...conservatism ain't a bad thing considering what happens when we ain't conservative enough.... :-D

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Of course I might not take advice on dive computers from someone who really thinks "ain't" is a word... :-D

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Beer, BBQ, and Blue Bell - Texas Dinner.
Ain't that grand~! :-D

Andrew

I agree with jpdiver in the fact that the HE is more conservative than the VR3 (with the VR3 conservatism set to 0). I found this out while diving with both computers.

Some facts to keep in mind when choosing a new dive computer are features (capability, user replaceable batteries, decompression models, computer upload / download, ... ), reliability, cost and support. You might also keep in mind; opinions may differ biased upon the computers firmware version (Ni Tek 3, VR3, Hydrospace Explorer ...).

I really like my NiTek 3, but I am concerned about computers that are manufacturer discontinued. The NiTek 3 works great for technical dives and it’s a very popular computer. It’s very easy to use and supports multiple gasses up to 99% oxygen. However, be cautious of buying used computers. Some older models have some unexpected features. One firmware model resets its gasses after a 10 minute surface interval. Another firmware model resets itself at midnight. I had the reset at midnight feature. I contacted Dive Rite and they replaced it. Dive Rite has excellent customer service, but I don't know if their warrantee is transferable. Dive Rite recommends you send the NiTek back to them, to get the battery replaced (it’s a good thing the battery lasts a long time). The NiTek He is a great trimix computer and it’s a spin-off of the NiTek 3, but designed with more functionality.

I really like the VR3, but its very confusing to navigate it’s menus in the beginning and you have to send it to the UK to get the computer serviced. If you buy a VR3, it might be useful to have another VR3 user help you learn how to operate the computer a little quicker. The VR3 works for open circuit and closed circuit diving, it handles air to trimix gasses. The VR3 also allows you to change the conservatism setting (this adds deep stops). The VR3 eats AA batteries, but they are user replaceable. Some users of older firmware VR3s have had problems. Some newer versions of the VR3 firmware have a BIG LETTER option. The VR3 is a computer which is capable of having its firmware changed, by the manufacture, to add new features and functionality. If you don't need all the features of the VR3, you may consider the VR2.

The HydroSpace Explorer is another feature rich trimix computer. Some older versions of the firmware had problems, but I really like the true RBGM model. The HydroSpace Explorer also allows open and closed circuit diving. It’s capable of gasses from air to trimix. The Explorer allows you to change its conservative setting and decompression models. It also has user replaceable battery capability, although it doesn't use standard AA batteries. HydroSpace is located in Florida and they have been very good about supporting their computers. The HydroSpace Explorer is a computer which is capable of having its firmware changed, by the manufacture, to add new features and functionality. You can find a HS Explorer simulator and user manual on the HydroSpace web site.

Suunto also makes very nice dive computers, but they are well known for being very conservative. As REastman pointed out - the Vytek uses the Suunto RBGM. Suunto has some of the best personal computer dive log books, which integrate with their dive computers. Some of their computers are feature rich and allow you to tweak parameters to customize the decompression model to fit closer to an individual user. The Vytek isn’t a trimix computer. You can find a user manual on the manufactures web site.

For a trimix computer, which meets my needs, my first choice would be a VR3, followed by the HyrdoSpace Explorer and then the NiTek He.

If you only plan on using nitrox or oxygen, for open circuit technical diving, the NiTek 3 would be my first choice.

In addition to the posts you might want to check the archives (for more opinions on dive computers), the manufactures web sites, or other web sites to find out additional information on the computers that interest you. Here are some links which might help:

For comparisons:
Check on this forum under Resources, Gear, and then Computers
http://www.hs-eng.com/Comparison.htm

Some dive computer manufactures:
http://www.dive-rite.com/products/nitek/index.htm
http://www.vr3.co.uk
http://www.hs-eng.com
http://www.suunto.com

Chip great posting sir. Did you ever read about Dr. Mayo and his dive that he was bent on? That was 0% conservation on his vr3. Story can be read at: http://www.snoopyloop.com/Exped%20Go...ed%202003.html

When I was at DEMA the folks at VR3 commented that the computer should have a few new features added to it. As you know they have the bigger letters, plus multi colored segments of the screen and there was talk of revising the menu layout for easier access and learning. If a certain programmer is lurking he probably could say more- Ethan?

There is a topic section in Resources which we made a comparison chart.
http://www.cavediver.net/archives/co.../computers.htm

Other computers not mentioned are the Nexus from Inspiration group and it is a rather outdated style of three touch points, and tapping the screen for gas changing. However, I have seen them cheap. I believe this was produced by the Benthic group out of Europe.

Cochran has a few computers and people like them or hate them. I try to like them as much as possible but they just have not grown on me. Updates to there line has included some new features and software changes. This group has been one of least cooperative about their algorithm and they will not talk about it. Howard Hall probably one of their better known users has recent gone to the VR3.

Has anyone considered starting a consortium and designing a totally new computer?

[left click] [right click] {both click} I [right click] absolutely {both click} love the [right click] [left click] VR3!!

{both click} {hold both}

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Originally Posted by crazyduck

Chip great posting sir. Did you ever read about Dr. Mayo and his dive that he was bent on? That was 0% conservation on his vr3. Story can be read at: http://www.snoopyloop.com/Exped%20Go...ed%202003.html

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You failed to mention the fact that he was telling the VR3 the Helium content on his deco gases was much less than it actually was, "to prevent being penalized too much". He obliterated any deco schedule the computer gives to him when he started lying to the computer. Also notice that under Epilogue, he stated that next time they will use "VR3 pre-programmed gas 50/25 and 35/35 instead of pre-programmed 50% and 35/20".

Mike

Thanks for the complement crazyduck. No, I haven’t read about Dr. Mayo and his dive that he was bent on. I plan on reading it in the near future. Thanks for turning me on to another good diving website.

I am not recommending that anyone dive with 0% conservatism. That’s an individual’s personal decision. I just happened to be running the VR3 in that mode. I usually add extra deep stops and other safety margins, if I run the VR3 with 0% conservatism. Also, I usually dive my VR3 with an external oxygen sensor in closed circuit mode. I am using the firmware version prior to the BIG LETTER upgrade.

Yes, I heard about the new VR3 upgrade and mixed user reactions to it, on a rebreather news list. Sometimes new features have bugs, which need to be corrected. I have a lot of confidence in Kevin G. It might also be good to mention the VR3 is based upon ProPlanner.

I also dive a Buddy Nexus. It is a very good nitrox computer made by A. P. Valves. Its easy to program and has both a close circuit and open circuit mode. It has a conservative setting; called dive conditions selection function, although it is limited to two options (a 0 or 1, with 0 being a normal setting and a 1 being the short table setting). Another great feature of the Nexus is that it has an auto switch depth selection function (it can be turned on or off). This feature automatically switches your oxygen setpoint in closed circuit mode, or your gas in open circuit mode, depending upon what user switch depth is programmed into the computer. You have two switch depth settings (one for descent and one for ascent). You can also override the switch depths manually. For open circuit, gas 1 is defined to be 21% - 50% and gas 2 is defined up to 100% oxygen.

I agree with you about your love / hate statement on the Cochran dive computers. I have a Nemesis IIa Nitrox dive computer. It’s a three gas nitrox dive computer. It can be programmed with a field programmer or by a personal computer. It’s capable of decompression mixes up to 99% oxygen. One of the selling points of the Nemesis IIa is its ability to be integrated wirelessly into a Cochran heads up display (HUD), which was to produce a computer screen like display inside a Cochran HUD mask. The Nemesis IIa has a large wireless transmitter, which hooks up to a high pressure port on a diver’s first stage. This sends a signal to the wrist computer. The Nemesis IIa automatically detects when you quit breathing your first gas source and it then switches to your second mix. It also has a programmable depth auto switch feature for your third gas mixture.

Cochran has a very feature rich dive computer log book and programmable interface for their dive computers called Analyst. Using Analyst you can program your dive computer with your gas mixes, switch depth and custom user parameters to tweak your individual decompression profile.

Another interesting point is a dive comparison between a VR3 and an Explorer with RBGM. The RBGM Explorer gives lots of additional deep stops (more dive table like), as opposed to the VR3 (with 0%). It takes the Explorer longer to process its RBGM computer model, so it shows a greater total time to surface. Eventually the RBGM Explorer clears before the VR3 on the shallower stops. I saw a caution about diving the RBGM Explorer on repetitive dives, on the same day, using the RBGM model.

If we venture further away from the original post, we could talk about rebreather dive computers. The Hammerhead can be used as a separate open circuit dive computer, but its primary use is to be attached to a closed circuit rebreather (CCR). It’s a trimix dive computer, which monitors three oxygen sensors and takes an average, to control the firing of a solenoid, to maintain a user defined set point (which can be changed during the dive). It has a primary and a secondary handset. The primary contains a trimix computer and the secondary controls the diva (a vibrating HUD). The Hammerhead has a user defined custom gradient factor for computing decompression. The Hammerhead can be used on many different rebreathers (Inspiration, Kiss, Mark 15, Mark 16 and the new Dive Rite CCR) and the handsets are designed to be interchangeable between different rebreathers.

I don’t know if anyone has considered starting a consortium to design a totally new dive computer. I do know many of the new trimix dive computers are evolving while I am typing on my computer. I work on computers and programming for a living. My obsession with diving (like so many others on this list), dive technology and dive computers has turned me into a divecomputeraholic. I haven't found a dive computer yet, which has all the features which I desire!

It looks like Widiver_Paul already has learned the VR3 and Mike H. has a very good point about programmable dive computers. Garbage in equates to garbage out. This is a general statement about programmable dive computers and I haven’t read Dr. Mayo’s report, so my comment doesn’t refer to his situation.

I hear a lot of people complain about the cost of dive computers (myself included). Dive computers are used for life support and most models cost less than a personal computer. How much is your life worth?

Dive safe, dive often and have fun … Chip

Correction-
The gentlemans name at snoppyloops is "Dr Jerome Meynie." My fault for not double checking. No harm was intended towards Mr. Meynie or his group.

Regards, Andrew

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Originally Posted by crazyduck

When I was at DEMA the folks at VR3 commented that the computer should have a few new features added to it. As you know they have the bigger letters, plus multi colored segments of the screen and there was talk of revising the menu layout for easier access and learning. If a certain programmer is lurking he probably could say more- Ethan?

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Somehow I have a suspicion that you're talking about me. :D I can't really say anything about the new "version 3.0" - I don't have mine yet and I don't get inside information. Documentation on the new features is available here:

http://www.vr3.co.uk/downloads/flyer...Guidelines.doc
http://www.vr3.co.uk/downloads/manua..._V3_manual.pdf

The menus in the VR3 really aren't that bad. At first, I had a lot of trouble with them, but then I played with it for a couple hours during a long car drive. After that, it's very intuitive - working through the menu structure becomes second nature. Everything is placed logically - once you set it up on the surface before the dive, interaction in the water is mainly "confirming" gas switches.

If anyone is considering purchasing the VR3 but is intimidated by the menus, Delta P (the manufacturer of the VR3) now has a simulator available. Note that it is intended as a "user interaction" simulator to let you get the feel for the menus and behavior. You can set it up and then go through a simulated dive and deco (in real time or at 10x speed). The only requirement is that you have a web browser that supports Java applets.

VR3 Simulator

Ethan

lol, the lesson being that if you really want to make the VR3's menus second nature, then start using it while driving - if you can avoid getting your car bent while working on the VR3, you can probably avoid getting bent yourself as well :)

(couldn't resist)

For what it's worth, I managed to get bent on one of those ultra-conservative Suuntos. Dived to plan, took the extra 11 mins of deco that the computer gave me over what I'd have done from tables on a 20 minute bottom time dive, and still got bent. I was dehydrated before starting that dive, which is probably the main reason. Sometimes, it's just going to happen.

Quote:

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Originally Posted by Stu

lol, the lesson being that if you really want to make the VR3's menus second nature, then start using it while driving - if you can avoid getting your car bent while working on the VR3, you can probably avoid getting bent yourself as well :)

(couldn't resist)

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Thats how they tested it- NASCAR! Oval track at 200 MPH, and no gators.
:twisted:

Just joking, the altertive requires cave line lots of trees and hanging beer bottles. After every bottle you have to confirm your gas, and hang the bottle. You cannot move back or forth more than 3ft. If so you are penlized and have to drink another beer. Renmenber 30 feet per minute between stops. IF you want to get mean blind fold the partipants and run it through a area with stumps. :-D

Later, Andrew

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Originally Posted by Chip

I really like the VR3, but its very confusing to navigate it’s menus in the beginning and you have to send it to the UK to get the computer serviced.

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Chip, thanks for the really informed info on here about the computers. I'm sure by the time I get writing this, there will be a firmware change or a new computer out there!

Just thought I'd comment that I know for a fact that Kevin G. is working hard to make the company more U.S. friendly, including (censored)--------------------------------------------------------------- It's second best to having manufacturing over here, but after what happened with Abyss, I don't blame them for wanting to stay at LEAST 1000 miles away from any American attorney on his home turf.

They've also changed their pricing structure so that you're not at the whim of the International monetary exchange rates, you can now purchase with your credit card without getting penalized like you used to with an exchange fee, etc. from your CC company. They've got the new color LCD's out now (very pretty, can you see color at 300'?) and the best new feature i've been waiting for is finally on the way in, (censored)------------------------------------------------------------------------------------------- Along with some menu changes and all the other features it looks like they're at least interested in perfecting near-perfection. Now if only they could drop the price by half and include all the upgrades!! I know, i'm asking way too much. But I can dream. I'll be selling at least one of my children on E-bay (probably the mouthiest one first) and buying one this year, i'm tired of my Uwatec going into "Oh, hell no! Now you've gone and really done it this time, you idiot!" mode after doing mixed gas dives...

-Paul

Does anyone know WHEN the VR3 is going to have VPM in it? And will it be original VPM, or VPM-B?

Email to the VR3 folks over on the other side of the pond has gone unanswered.....

Anyone use the download and Prolog divelog for the VR3?
I'm looking for any info on Prolog - opinion/ screenshots/ anything.

How about the dive rite download software?

Thanks

Quote:

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Originally Posted by MikeH

Try this next time, Rich. Cut your tables and stick to the EXACT dive plan on the tables. Don't put 300' for 20 mins, then spend 2 mins at 300' and 18 mins ascending from 300' to 150' before starting your deco. If you put 300' for 20 mins, spend that long there. Put in realistic descent/ascent rates. I'd be willing to bet your HE will NOT get you out of the water quicker in this case.

Of course, I don't cut backup tables for max depth and run those profiles....I cut them for average depth(20ft intervals, 40ft each way of expected average). I've done quite a few mix dives with my VR3 with somebody else using an HE....and for the same profile...my VR3 always clears much faster. The Nitek series are too conservative. Call DR and ask them what the level of conservativeness is compared to their deco software....I think it's around 50%...I was told once, but don't recall the exact number. Granted, the VR3 has a bit longer runtimes than tables...but on a 250' 25 minute dive, it's usually within 3-5 minutes. The VR3 likes to deco longer at the deeper stops, and shorten the time at the shallower stops...til the 10' stop.

Mike

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Not to criticize or anything, but I;ve never understood why everyone is so intent on geting out of the water so fast. Perhaps conservatism is a good thing. :-D

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Originally Posted by Widiver_Paul

Chip, thanks for the really informed info on here about the computers. I'm sure by the time I get writing this, there will be a firmware change or a new computer out there!
-Paul

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You are welcome! Wow, a blast from the past.

Your timing is very bizarre, because I went to visit Gene Melton with Hydrospace Engineering on Sunday. I upgraded my Explorer to a model O and I checked out his new rebreather kit.

Quote:

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Originally Posted by Gary

Anyone use the download and Prolog divelog for the VR3?
I'm looking for any info on Prolog - opinion/ screenshots/ anything.

How about the dive rite download software?

Thanks

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Gary,

The VR3 interfaces with a PC by using an IR link, which is located towards the top of the VR3 display.

I have Prolog for the VR3 and it's really neat. It opens up under my name (which I defined) and it contains a dive log, gas blends and dive locations. The dive log contains my downloaded dives in the following format:
"Dive on 1/8/05 at 13:58", "Dive Log Number", "Date", "Location" and "Site".

When you double click on the dive name it pulls up a three tab page. The tabs are "General", "Profile", Gas" and "Series". The “General” tab has date, log, dive name, time down, time up, max depth, duration, buddy, location, site and dive notes. The “Profile” tab has a plot of your dive with the time, depth, average depth, max descent, max ascent, max PO2 and CNS. This page has a feature to zoom in or out and you can pinpoint a location in the plot and it will tell you the time and depth. It also has point properties, area properties, an ascent rate plot and PO2 plot. The “Gas” tab contains the mix or mixes you used on the dive. Finally, the “Series” tab gives you all the dives in that dive series.

Under “Gas Management” you can select or define gasses and setup gas profiles. These gasses can then be uploaded to the VR3. The “Locations” is an area where you setup your dive locations to be used in your dive log.

You might want to check out the Delta P Technologies web site http://www.vr3.co.uk/ because they announced “New for 2005!! The new VR PC Link Software Suite available NOW!! Click for further details”. This looks very interesting.

I also have used the Dive Rite download software called NiTek Logic version 3.03 http://diverite.com/products/nitek/logic.htm (the latest version is 3.06). It's a logbook program that downloads and stores dives from several of the Dive Rite computers (NiTek, NiTek 3 and the NiTek He). NiTek Logic interfaces with a PC through a docking station with a serial interface. You can download NiTek Logic from the Dive Rite web site to get a flavor for what it’s like.

NiTek Logic opens up into a logbook with download dive series under the main logbook. The content of each dive series contains a listing of the following information:
“Name”, “Description”, “Date”, “Time In”, “Bottom Time” and “Computer Type”. Double clicking on the “Name” brings up the dive profile in a 3D plot with the following information: Date, Orig Date, Time In, Time Out, Dive Time, Max Depth, Avg Depth, Temp, Sample rate, Mix, Decompression Dive, Deco Stop Violation, Ascent Rate Warning, Out-of-Range Error, Max Deco Violation, OLI Violation, Nitrox Range Violation, Freshwater, Gauge Mode, Safety Factor, Buddy(s) and Equipment. NiTek Logic also has an interface for the Voyager dive planning software.

Both logbooks are very nice, so it really depends upon your dive computer!

Quote:

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Originally Posted by REastman

Not to criticize or anything, but I;ve never understood why everyone is so intent on geting out of the water so fast. Perhaps conservatism is a good thing. :-D

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Ryan,

My take is ... I want to know the soonest that I can get out of the water and I usually add a safety margin on top of that. My safety margin is a combination of things, but it usually consists of waiting for my open circuit buddies to clear their dive computers. :)

Some ProLog screen shots and free getting started with Prolog Guide at

http://www.vr3.co.uk/vr3/main.php?content=prolog

I will try to post some screen shots of ProLog and NiTek Logic in the near future.

The VR3 logbook has an interactive display with the dive plot. If you loose battery power in the dive computer, you will loose your downloadable dive information. I replace my VR3 battery quite often, but I have never had to replace a battery in a NiTek 3 or He.

Quote:

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Originally Posted by Chip

I will try to post some screen shots of ProLog and NiTek Logic in the near future.

The VR3 logbook has an interactive display with the dive plot. If you loose battery power in the dive computer, you will loose your downloadable dive information. I replace my VR3 battery quite often, but I have never had to replace a battery in a NiTek 3 or He.

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Great information Chip - thanks.

So which computer do you prefer - the HE or the VR3?

I've got 1000 dives stored in Bridge dive logs that I can't seem to import anywhere else and I plan on changing over to something at the 1000 dive point that will last me the next 1000 dives.

Anyone know of any dive logs that can import CSV or tab delimited values? (or any other data format for that matter.)

(and please do post more screen shots - it seems that those 3 are hardly the whole story)

I've dove both computers you're looking at and have a word to say about each.... I first owned a cochran, and still do, it makes a great paper weight. I bought it because it was a cheaper option for a two gas nitrox computer and I got it used. I dove it for about a year and then one day before doing a dive for work, my boat captain got on the topic of dive computers and how he hated Cochrans... I walked into the bridge and quietly said.... "I dive a cochran....and I love it... i think".... believe it or not....no crap, the computer died on that very dive..... it didn't turn on when I hit the water and I noticed it about 20' down...i played with the contacts and got it to turn on, then it immediatly turned off and continued to go on and off for the whole dive... I changed the battery when I got home and it still doesn't work to this day. cochran was really crappy about helping me in any way... they said they would upgrade me to a new one for a few hundred bucks, but I figured why would i want another after this one died on me?
I bought a nitek duo (watch style two gas nitrox computer) shortly after that dive without knowing much about them. I absolutly love this computer. I put over 300 dives on it this summer season working as crew on a dive boat and I couldn't ask for a better computer for what I do. Easy to switch gases, easy to use, easy to read, and very very reliable. The only trouble i've had with it is that the temperature guage on occassion would read 32 degrees... I sent it in this past fall after our dive season was over and I got a brand new one back two weeks later. Great product, great company!
Good luck on your search, there are a lot of them out there!
-Matt

Quote:

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Originally Posted by Gary

So which computer do you prefer - the HE or the VR3?

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The VR3, no question about it! Most of my dives are closed circuit and the HE only does open circuit. You can use the HE to model your gas profile, and do lots of gas switches in close circuit mode, but why. The VR3 also has an option for an external oxygen sensor connection, which I use. With this, the VR3 calculates decompression based upon the gas in my loop. It also serves as a backup PO2 monitor. The VR3 is software upgradeable, it supports 10 gas mixes (which can be changed underwater) and the list goes on.

The NiTek He is a nice trimix computer, but it's not a VR3. It will be very interesting to see if Dive Rite comes out with a close / open circuit trimix dive computer in the near future. Their new closed circuit rebreather will use the Hammerhead electronics (built-in trimix computer), but will the NiTek He evolve?

Quote:

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Originally Posted by Genesis

Does anyone know WHEN the VR3 is going to have VPM in it? And will it be original VPM, or VPM-B?

Email to the VR3 folks over on the other side of the pond has gone unanswered.....

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I've been waiting to hear something more definitive on that as well. Rumor mill says VPM-B due out this spring but then they say check with the folks across the pond to be sure. Would definitely like to have one if they do put the VPM-B in it any time soon.

I'd buy one tomorrow if it had VPM-B in it.

Even if I go to the dark side (CCR) this spring when DR comes out with their unit, it's still useful as a backup decompression computer, and VPM is my preferred algo for deco - at least so far :D

Quote:

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Originally Posted by Gary

Anyone use the download and Prolog divelog for the VR3?
I'm looking for any info on Prolog - opinion/ screenshots/ anything.

How about the dive rite download software?

Thanks

---

The NiTek He is a very nice trimix computer. It allows you to dive with air, nitrox, heliox, trimix and / or oxygen. You can set up to seven different gas mixes per dive and it can also be used in gauge mode. The FO2 can be set for 8% to 99%. The NiTek He displays your current PO2 during your dive. It comes with excellent customer service from Dive Rite, for original owner warrantee work (I’m not sure if the warrantee transfers for used computers). The NiTek He has a battery which lasts for a long time, and it’s easier to setup and use, because it doesn’t have as much functionality as the VR3.

Dive Rite Dive Computer Comparison Chart:

http://diverite.com/products/nitek/compare.htm

Free NiTek Logic download:

http://diverite.com/products/nitek/logic.htm

You have the option of downloading the full version of NiTekLogic 3.06 (1.6 meg), or the update - to upgrade your existing version of NiTekLogic to Version 3.06 (1.5 meg).

I originally downloaded the update and it didn’t convert my log files properly, so I downloaded the full version. Since I couldn’t get my log files converted, I just downloaded the current dives off my NiTek 3 and NiTek He to use for the screen shots.

NiTek Logic Version 3.06 works with the following dive computers:

Bridge II
Nitek (first generation)
Nitek 3
Nitek Plus
Nitek He
NiTek Plus USB

Requested screen shots:

http://cavediver.net/photopost/showp...medium&cat=501
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
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http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
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http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2
http://cavediver.net/photopost/showp...cat=500&page=2

Thanks Chip. Awesome really.

Dive Rite allows free download and has fairly good display of their software online. Truely it is the VR3 "Prolog" screenshots that would be of the most use since they have very little about thier software even in the directions for use.


And someone was asking: I saw that David Shaw's webpage had rumored a VPM model of the VR3 comming spring 2005.

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Originally Posted by Gary

Truely it is the VR3 "Prolog" screenshots that would be of the most use since they have very little about thier software even in the directions for use.

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VR3 features:

http://cavediver.net/photopost/showp...cat=501&page=1

ProDive (also known as Prolog) features:

http://www.mssystems.co.uk/prodive/pdpromo1/

VR3 ProDive download software screen shots:

http://cavediver.net/photopost/showp...cat=501&page=1
http://cavediver.net/photopost/showp...cat=501&page=1
http://cavediver.net/photopost/showp...cat=501&page=1
http://cavediver.net/photopost/showp...cat=501&page=1
http://cavediver.net/photopost/showp...cat=501&page=1
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http://cavediver.net/photopost/showp...cat=501&page=1
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I've been using a Nitek 3 for about five years and have never had a problem with it. My only criticisms are that it is bulky compared to the duo, and for most of the diving I do, I'm only using two gases anyway, so I could have really gone with that one. My second criticism is that for wreck diving, where the line is jumping up and down four or five feet when it's rough, it's really hard to get it to switch to 0-2 when it's showing you a twenty foot stop. A Dive Rite rep told me to set the 0-2 percentage to 90 rather than 99, but that bothers me on some level.

As far as the VR-3 goes, I don't own one yet but have played with it a bunch and one of the features I like best is the ability to run out tables with it. That's important when your dive destination gets changed and you need to prepare backup tables away from home, very handy.

I'd like to see it available with RGBM, that's what I'm really waiting for.

I asked Kevin Gurr, with Delta P Technology, if the VR3 is going to be released with VPM, VPM-B or RBGM and if so, when. His response was that they have VPM programmed right now and they are running trials. It’s probably 3 months away from being released. I also asked him if it was OK for me to post the ProDive screen shots and he gave me permission.

Quote:

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Originally Posted by Chip

I asked Kevin Gurr, with Delta P Technology, if the VR3 is going to be released with VPM, VPM-B or RBGM and if so, when. His response was that they have VPM programmed right now and they are running trials. It’s probably 3 months away from being released. I also asked him if it was OK for me to post the ProDive screen shots and he gave me permission.

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So that's VPM and NOT VPM-B?!

Oh well... there goes my rationale for buying one, especially if its VPM (original) IN PLACE of what's there now, instead of ALONG WITH it.

WHY would they do something like that? Makes absolutely ZERO sense to me!

I didn't ask him the technical details about how they were going to implement it. Hopefully, they will provide an option to choose a decompression model. I like the current VR3 decompression model, but having other choices would be desirable. Yes, it would be nice to have VPM-B instead of VPM.

My uninformed opinion is that the VPM-B is so new and dependant on the ongoing feedback is that in it's somewhat "untested" state there may be not enough data to make it reliable for something as dependable as the VR3. I know RGBM is still looked at suspiciously in some circles; I think it's fortunate that Kevin is willing to invest his trust in the VPM algorithm where others just jump in the same boat with the other manufacturers in sticking with only Buhlmann tables (that were experimental themselves not so very long ago). Kudos to Delta P for being vanguards and trying to make diving safer for us. I know lots of divers that were waiting for just this change in a dive computer. It's great we won't have to buy some cheap recreational model to reap the benefits.

I guess I'll have to wait until someone has one I can look at before plunking down the money....

This much I know for sure - I ain't buying the current model with this one around the corner, given that there's no US-based way to get it updated, and I think its reasonable to assume that the updates won't be free!

I disagree on the VPM/VPM-B point of view. There's nothing at all to stop them from having both available - the current Vplanner code does - and that would make the decision one for the diver to make.

Hopefully they'll put VPM/VPM-B/Buhlmann+GF in there, so you'll have what they've got now, plus the two VPM varients you can choose from. THAT would be nice.

Quote:

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Originally Posted by Widiver_Paul

My uninformed opinion is that the VPM-B is so new and dependant on the ongoing feedback is that in it's somewhat "untested" state there may be not enough data to make it reliable for something as dependable as the VR3. I know RGBM is still looked at suspiciously in some circles; I think it's fortunate that Kevin is willing to invest his trust in the VPM algorithm where others just jump in the same boat with the other manufacturers in sticking with only Buhlmann tables (that were experimental themselves not so very long ago). Kudos to Delta P for being vanguards and trying to make diving safer for us. I know lots of divers that were waiting for just this change in a dive computer. It's great we won't have to buy some cheap recreational model to reap the benefits.

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How do you figure it to be untested? IANTD has been using VPM-B based tables for some time now.

Quote:

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Originally Posted by DeWayne

How do you figure it to be untested? IANTD has been using VPM-B based tables for some time now.

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Just a matter of which one's been around the longest. Up until the last decade we were still using Haldanean models, which are almost 100 years old because they were tried and true...

Quote:

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Originally Posted by DeWayne

How do you figure it to be untested? IANTD has been using VPM-B based tables for some time now.

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A link for V-Planner VPM-B: http://www.hhssoftware.com/v-planner/

Information on the VPM-B model:
(The information listed below is from
http://www.hhssoftware.com/v-planner/vpmdetail.html ):

VPM-B is a revision by Erik Baker to his original work and the model described below. The change was to include Boyles Law compensation to the ascent gradients that determine ceilings and times of stops. This one additional set of calculations in the model, corrected a number of concerns about plans from the Original model.

The output from a VPM-B profile is a plan that retains both deep stops, and modest amount of time in the shallow areas. A significant amount of diver feedback has confirmed that the VPM-B model is valid across a wide range of dive profiles. From a gentle NDL dive, to a normal double tank deco dive, or a deep CCR dive.

VPM-B is the newest and most accurate bubble model available. The VPM-B model on it's own, produces consistent decompression plans for the entire range of dives, and accurately intercepts the NDL limits as well. VPM-B does not require any modifiers or factors or other mathematical hacks on the input parameters, etc. i.e. no GF's or pfac, bfac, factors, or other trimming methods to arrive at the "right" result.

2002
VPM use in recreational tech diving grows. Model is adapted for use with CCR planning. Diver feedback and documented experiences grow. Initial data suggests the model is valid, but is somewhat range bound. Erik Baker starts work on a revision to the original model (described above). This results in a change to calculating ascent ceilings by including a Boyles Law compensation. Revised model is named VPM-B.

2003
February: V-Planner with VPM-B released at the NAUI Deep Stop conference.
IANTD includes VPM-B tables into all new training courses.
VPM enters commercial work as an approved decompression program with the Danish Maritime Authorities.
V-Planner program further developed to include many of the current tech diving planning features and practices.

I've researched the math behind both VPM and RGBM beofre deciding which to trust. The mathematical modeling in VPM is much cleaner and progressive while Bruce relies on older analysis models, which is indeed typical for most physicists. I have found small glitches in RGBM, true it would take a lot of deco time for them to ever make their pressence known, but they are there. Have yet to be able to make the VPM model fail that way. My background btw is in theorectical mathematics, noncommutative algebras and quantum groups.

More information on VPM and other decompression models:

VPM Decompression Site:
http://www.decompression.org/maiken/...m_Site_Map.htm

RBGM:
ftp://decompression.org/pub/Wienke/

Decompression information:
http://www.deepocean.net/

Decompression model comparisons:
ftp://decompression.org/pub/Maiken/
ftp://decompression.org/pub/

Quote:

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Originally Posted by Genesis

So that's VPM and NOT VPM-B?!

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I got a response from Kevin about the future VR3s. When you buy a new VR3 you have a choice of the current decompression model (derivative of the Buhlmann ZH-L16 algorithm (includes microbubble stops), the exact same derivative used in the Proplanner decompression software) or VPM. If you upgrade, you can swap to VPM. So it appears that each VR3 will only have one onboard decompression model.

But WHICH VPM?

Sounds like I'm out of the market on this one..... barf. (no simulator aka Proplanner for the VPM version either?!)

Somehow I need to be able to cut backup tables that MATCH the computer's profile! These guys have to understand that... no?

Quote:

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Originally Posted by Genesis

But WHICH VPM?

Sounds like I'm out of the market on this one..... barf. (no simulator aka Proplanner for the VPM version either?!)

Somehow I need to be able to cut backup tables that MATCH the computer's profile! These guys have to understand that... no?

---

I specifically asked about VPM, VPM-B or RBGM. The answer I got was VPM.

I agree - you need software to cut bailout tables which MATCH! The VR3 has the built in ability to cut future tables, biased upon your past dive, but I don't know if they are going to offer a VPM version of ProPlanner.

You can download VPM dive planning software, but I don't know if it will be an exact match for the VR3 (it should match, unless they modify VPM).

Trimix Computer Deco Models & Dive Planning Software:

VR3 - derivative of the Buhlmann ZH-L16 algorithm (includes microbubble stops) (free user’s manual at http://www.vr3.co.uk/vr3/main.php?content=manual )

HS Explorer – 10 decompression models (free user’s manual at http://www.hs-eng.com/manuals.html )
CF 0 = RBGM, F=100, -light work, warm water
CF 1 = RBGM, F=97, moderate work, cold water
CF 2 = RBGM, F=94, -heavy work, cold water
CF 3 = ZH-L16C Computer, Dr. Buhlmann’s Computer Model
CF 4 = ZH-L16C Computer, Asymmetric 118, RBGM light work, warm water
CF 5 = ZH-L16C Computer, Asymmetric 118, RBGM moderate work, warm water
CF 6 = ZH-L16C Computer, Asymmetric 118, RBGM heavy work, warm water
CF 7 = ZH-L16C Computer, Asymmetric 135, RBGM light work, cool water
CF 8 = ZH-L16C Computer, Asymmetric 135, RBGM moderate work, cold water
CF 9 = ZH-L16C Computer, Asymmetric 135, RBGM heavy work, cold water

NiTek He – modified Buhlmann ZH-L16 algorithm (free user’s manual at http://diverite.com/products/nitek/nitek_he.htm )
Conservatism and the NiTek He http://diverite.com/tec_talk/conservatism/index.htm

Dive planning software links:
http://www.therebreathersite.nl/soft...ebreathers.htm
http://www.hs-eng.com/simulators.html
http://www.vr3.co.uk/vr3/main.php?content=simulator

I have VPlanner, which sports VPM capability as well.

For most of the "low-level" deco dives I do, VPM (orginal) is MORE conservative, in that it starts your stops deeper and takes longer to get you out.

However, this only holds for 'light' deco dives on Nitrox. The plans tend to converge around the 200' mark, and from there I understand that for really deep stuff VPM tends to underestimate the required deco.

Without knowing exactly what figures they've got in the algorythm, there's no way to know exactly what it produces, or if it can be reproduced with a table generator. If I can cut tables with VPlanner, and the VPM model they're using offers some form of 'tweaking' to get added conservatism if I'm not happy with the original, then it might be ok.

I still haven't gotten any response back whatsoever to my query to Delta-P on all of this however.... and buying a "serious" diving computer is not quite the same thing as buying a recreational computer for no-stop diving! I live with the "no real answers", or even what I consider misleading answers, from the rec computer folks - that simply won't do though when we're talking about a computer for this sort of use.....

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Originally Posted by Genesis

Without knowing exactly what figures they've got in the algorythm, there's no way to know exactly what it produces, or if it can be reproduced with a table generator. If I can cut tables with VPlanner, and the VPM model they're using offers some form of 'tweaking' to get added conservatism if I'm not happy with the original, then it might be ok.

I still haven't gotten any response back whatsoever to my query to Delta-P on all of this however....

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The beauty of VPM-B is that it shouldn't require tweaks (at least in theory).

I will ask Kevin some more questions. Hopefully, I will be able to get the answers for you.

Thanks....

In theory VPM shouldn't require any "tweaks" either. In practice it bent a bunch of people, which is why there's a "B" model, and even the "B" model is known to be a bit squirelly for truly extreme exposures... 8)

The thing is, Vplanner allows you to set the algorythm parameters, provided you know what to set them to. Toying with those constants is unwise in the extreme unless you do know what you're doing, of course, but I find it difficult to believe that Delta-P doesn't know that VPM tends to underestimate deco for deep dives, which would mean they did something to get to an acceptable end result, given their intended customer for the unit.....

This is the unfortunate reality of 'black box" computers and deco software - nobody wants to talk about what's really behind the curtain, and lack of that knowledge can hurt you. Hopefully this is changing - even if just a bit.

The open nature of Vplanner and how it "exposes" these constants where you can see them, and leaves the actual code out in the open where you can look at it, is one of the attractions from my perspective. None of the other algos or computers out there - none - do this. Not even the RGBM stuff.

I still hold a glimmer of hope that the new VR3 model is a computer that I can actually have some confidence in purchasing for this sort of diving - but Delta-P has some work to do in terms of available support for those of us in the US, and also in terms of getting out there exactly what's available and when. For instance, their web page still is mute about the upcoming VPM algo availability - yet you said that it was available now if one ordered a new unit.

It is a bummer that the original algo is not still available with the VPM one though - that would be very nice, as it would permit simple comparisons.....

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Originally Posted by DeWayne

I've researched the math behind both VPM and RGBM beofre deciding which to trust. The mathematical modeling in VPM is much cleaner and progressive while Bruce relies on older analysis models, which is indeed typical for most physicists. I have found small glitches in RGBM, true it would take a lot of deco time for them to ever make their pressence known, but they are there. Have yet to be able to make the VPM model fail that way. My background btw is in theorectical mathematics, noncommutative algebras and quantum groups.

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Wienke, B.R., Decompression Theory (ftp://decompression.org/pub/Wienke/ file named deco.pdf, pages 76 - 77):

“The RBGM has its roots in the earlier work of the Tiny Bubble Group at the University of Hawaii, drawing upon the so-called Varying Permeability Model (VPM) to multidiving, altitude, and mixed gas applications. While certainly not radical, the RBGM is both different and new on the diving scene. And not unexpectedly, the RBGM recovers the Haldane approach to decompression modeling in the limit of relatively safe (tolerably little) separated phase, with tolerably little a qualitative statement here.



Here, our intent is to (just) look at the underpinnings of both meter and diveware implementations of the RBGM algorithm, one with extended range of applicability based on simple dual phase principles. Haldane approaches have dominated decompression algorithms for a very long time, and the RBGM has been long in coming on the commercial scene. With recent technical diving interest in deep stop modeling, and concerns with repetitive diving in the recreational community, phase modeling is timely and pertinent. And, of course, since the RBGM extends the VPM, much of the following applies to the VPM directly.”

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Originally Posted by Genesis

For instance, their web page still is mute about the upcoming VPM algo availability - yet you said that it was available now if one ordered a new unit

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VPM isn't available for the VR3 yet, my words said the "future VR3s". The VR3 VPM release is “probably” 3 months away!

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Originally Posted by Genesis

It is a bummer that the original algo is not still available with the VPM one though - that would be very nice, as it would permit simple comparisons.....

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I agree, it would be very nice to have both (the original and VPM), but to do that you will need 2 VR3s.

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Originally Posted by Chip

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Originally Posted by Genesis

Without knowing exactly what figures they've got in the algorythm, there's no way to know exactly what it produces, or if it can be reproduced with a table generator. If I can cut tables with VPlanner, and the VPM model they're using offers some form of 'tweaking' to get added conservatism if I'm not happy with the original, then it might be ok.

I still haven't gotten any response back whatsoever to my query to Delta-P on all of this however....

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The beauty of VPM-B is that it shouldn't require tweaks (at least in theory).

I will ask Kevin some more questions. Hopefully, I will be able to get the answers for you.

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Ask him if they are close to having a date set for implementation. It will be very interesting to see what is finally released.

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Originally Posted by Chip

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Originally Posted by DeWayne

I've researched the math behind both VPM and RGBM beofre deciding which to trust. The mathematical modeling in VPM is much cleaner and progressive while Bruce relies on older analysis models, which is indeed typical for most physicists. I have found small glitches in RGBM, true it would take a lot of deco time for them to ever make their pressence known, but they are there. Have yet to be able to make the VPM model fail that way. My background btw is in theorectical mathematics, noncommutative algebras and quantum groups.

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Wienke, B.R., Decompression Theory (ftp://decompression.org/pub/Wienke/ file named deco.pdf, pages 76 - 77):

“The RBGM has its roots in the earlier work of the Tiny Bubble Group at the University of Hawaii, drawing upon the so-called Varying Permeability Model (VPM) to multidiving, altitude, and mixed gas applications. While certainly not radical, the RBGM is both different and new on the diving scene. And not unexpectedly, the RBGM recovers the Haldane approach to decompression modeling in the limit of relatively safe (tolerably little) separated phase, with tolerably little a qualitative statement here.

The Suunto VYPER is an RBGM-based decometer for recreational diving (plus nitrox), while ABYSS/RBGM is a licensed Abysmal Diving software product. On the Internet, the sites http://www.suunto.fi/diving.index.html and http://www.abysnal.com/index.html can be visited for information and description. Both are first-time-ever commercial products with realistic implementation of a diving phase algorithm across a wide spectrum of exposure extremes. And both accommodate user knobs for additional conservatism.

Here, our intent is to (just) look at the underpinnings of both meter and diveware implementations of the RBGM algorithm, one with extended range of applicability based on simple dual phase principles. Haldane approaches have dominated decompression algorithms for a very long time, and the RBGM has been long in coming on the commercial scene. With recent technical diving interest in deep stop modeling, and concerns with repetitive diving in the recreational community, phase modeling is timely and pertinent. And, of course, since the RBGM extends the VPM, much of the following applies to the VPM directly.”

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I corresponded with Bruce while I was looking into both models. From a practical application point of view what he has is great. From an anal mathematician's point of view, I found the VPM model to be cleaner and easier to work with and less prone to failures. Keep in mind that the runs I did to produce a failure far excede what any human would ever be capable of, and were infact quite minor at that point. Both have been great as a platform for looking at an even more inclusive model that perhaps one day I will be able to work the kinks out of.

Man, am I sorry that I asked this question. I have decided to construct my own computer. I am sealing a small cat inside a 1 gallon Mason jar, hooking up a second stage to the lid so the cat is in ambient pressure, and breathing the same gas that I am. Then as I ascend, when the cat starts to look really uncomfortable, I will stop until it calms down. Plans for this computer will be available on PETA's website under the extreme cruelty to animals section by late next month. I refer to this as the T.V. algorithim (Tender Vittles). Naturally, if you are not careful during the dive, and break the "lens", you would have a cat-a-strophic computer failure. Ther only real design issue left is how to get a litter box in the jar.
Cat Diapers. Thet's the answer.

The scary part of the cite you provided above from BRW's paper is that its not actually true.

The Vyper is NOT a true RGBM meter, nor is any other Suunto. They all run a Buhlmann/Haldane-style algorythm with a "folded" RGBM piece of code on top of them. NONE of them produce deep decompression stops.; indeed, all show ceilings that, if followed, produce a straight Buhlmann/Haldane-style decompression curve! The decompression ceilings they display produce profiles that are wildly at odds with the current thinking regarding deco. Near as I can tell (Suunto won't disclose specifics) the ONLY influence the "RGBM" stuff has in there is to produce reduced no-stop times for repetitive diving.

You CAN dive them with a modern decompression curve, but YOU have to do it manually - the computer sure won't. I own three of Suunto's products, by the way.... and have a LOT of dives on them - I know exactly what kind of decompression "suggestions" they produce.

This is what I call "math meets marketing", or, to perhaps be a bit rude, "math meets money." More to the point, it entirely removed my interest in RGBM; I expect straight answers to questions when it comes to software like this - and this sort of statement is IMHO a credibility-destroyer.

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Originally Posted by Genesis

The scary part of the cite you provided above from BRW's paper is that its not actually true.

The Vyper is NOT a true RGBM meter, nor is any other Suunto. They all run a Buhlmann/Haldane-style algorythm with a "folded" RGBM piece of code on top of them. NONE of them produce deep decompression stops.; indeed, all show ceilings that, if followed, produce a straight Buhlmann/Haldane-style decompression curve! The decompression ceilings they display produce profiles that are wildly at odds with the current thinking regarding deco. Near as I can tell (Suunto won't disclose specifics) the ONLY influence the "RGBM" stuff has in there is to produce reduced no-stop times for repetitive diving.

You CAN dive them with a modern decompression curve, but YOU have to do it manually - the computer sure won't. I own three of Suunto's products, by the way.... and have a LOT of dives on them - I know exactly what kind of decompression "suggestions" they produce.

This is what I call "math meets marketing", or, to perhaps be a bit rude, "math meets money." More to the point, it entirely removed my interest in RGBM;

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My comment was in regards to Dewayne’s statement about RBGM. I thought about leaving out the paragraph about the Suunto and Abyss computers, but I left it in. Both web links don't work and the Suunto is a modification of RBGM (Suunto RBGM).

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Originally Posted by Genesis

I expect straight answers to questions when it comes to software like this - and this sort of statement is IMHO a credibility-destroyer.

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I'm only trying to help here! I posted some of what was written on RBGM and I'm sorry if you didn't like it.

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Originally Posted by OFG-1

Man, am I sorry that I asked this question. I have decided to construct my own computer. I am sealing a small cat inside a 1 gallon Mason jar, hooking up a second stage to the lid so the cat is in ambient pressure, and breathing the same gas that I am. Then as I ascend, when the cat starts to look really uncomfortable, I will stop until it calms down. Plans for this computer will be available on PETA's website under the extreme cruelty to animals section by late next month. I refer to this as the T.V. algorithim (Tender Vittles). Naturally, if you are not careful during the dive, and break the "lens", you would have a cat-a-strophic computer failure. Ther only real design issue left is how to get a litter box in the jar.
Cat Diapers. Thet's the answer.

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This is the damn funniest thing I have read in months!

YOu need to send this to Overhead TImes under the Humor Section.

OH MY GOD! Here is your sign.

PS- someone needs to add an alert warning. I sprayed my keyboard and I am not a CAT.

Andrew

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Originally Posted by Genesis

I expect straight answers to questions when it comes to software like this - and this sort of statement is IMHO a credibility-destroyer.

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I seriously hope that you are referring to distribution channels and manufactures and not all of the hard work that Chip has done by bringing this all together. A little clarification here would be a good thing! :evil:

For those of us that have been battling with manufactures over the release of information, this has been a great thread. I wish that we could bind this kind of material and hand it out to friends who are buying new dive computer. Some people have no idea all of the things that go into these little jewels.

Andrew

I understand Chip, and please be aware that I'm NOT in any way attacking you or what you're doing here, but to me, at least (and I hope to others!) marketing hype is a major problem when it comes to stuff like this.

After all, we're expected to trust that these implementations won't turn us into pretzels. Its just a wee bit more important than most of the other marketing hype out there...

I understand what you were doing, but in doing so you illustrated one of the problems in the industry when it comes to meters and software - its not exclusive to RGBM, but this just happens to be one of the screaming examples of hype over substance.

RGBM in general is one of the wildest examples of this. Find the various meters and programs out there that claim to be "RGBM", plug in a given dive, and note something nasty - they all spit out different profiles. Which one is "true" RGBM? Who knows! This is the general problem with not knowing where the "knobs" are set, and there being no proclaimed "correct" place to twist them to point.

I'd LOVE to find just ONE meter intended for technical diving where its ALL laid on the table, where the deviations from the model's designer are documented, and where you can twiddle them back to the designer's intended settings (or to other settings as the designer changes his/her mind - or mathematics!) change.

The VR3 is uniquely suited to this possibility, since it CAN be reprogrammed. Delta-P has not seen fit to make it possible to do without returning to them (perhaps for liabiltiy reasons, or perhaps for business reasons) but the capability, when the VR3 was first announced, excited me - simply because for the first time "its all hardcoded" was no longer true.

Sadly, its turned out not to matter much in reality, which is a bummer. I was hoping that the VR3 would make use of its IR interface capability to make possible flash updates, much like we do with a PC BIOS.

If you deep dive, my Duo is off on depth. On a recent deep dive, my Duo read 318 feet, which was off by about 40 feet. For shallower cave dives, it seems fine, and I like the big letters. It's good for cave dives requiring just two mixes, fine for most of my diving.

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Originally Posted by Genesis

I'd LOVE to find just ONE meter intended for technical diving where its ALL laid on the table, where the deviations from the model's designer are documented, and where you can twiddle them back to the designer's intended settings (or to other settings as the designer changes his/her mind - or mathematics!) change.

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How about your brain? Models are models, and none of it is real. Follow a well tested model until you know what you're doing, then do what you know. Dive computers will always be BS, because behind each one is a company that can be sued.

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Originally Posted by Al

Quote:

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Originally Posted by Genesis

I'd LOVE to find just ONE meter intended for technical diving where its ALL laid on the table, where the deviations from the model's designer are documented, and where you can twiddle them back to the designer's intended settings (or to other settings as the designer changes his/her mind - or mathematics!) change.

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How about your brain? Models are models, and none of it is real. Follow a well tested model until you know what you're doing, then do what you know. Dive computers will always be BS, because behind each one is a company that can be sued.

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As soon as you find a brain that can accurately compute multi-level dives (of which most cave dives are) and has a lower error rate than a machine I'd agree that "computers will (always) be BS". While there are claims that the first can be achieved, I don't see the second happening so long as we're human rather than bionic.

BTW, what's the difference between a computer in your truck (cutting tables) and a computer on your wrist (cutting tables)? Both do the same thing; the salient difference is that one of them has more accurate information to work with than the other.

I don't mind a model; indeed, all theoretical processes are described by same, and while none are perfect, they don't have to be in order to be useful. What I do object to is something that claims to be a thing it is not, or a claimed model that departs from what the model actually IS, without any documentation as to exactly what was modified! Its not possible to apply one's brain to evaluating the recommendations made by any model if one doesn't know what has been done to it.

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Originally Posted by Genesis

I don't mind a model; indeed, all theoretical processes are described by same, and while none are perfect, they don't have to be in order to be useful. What I do object to is something that claims to be a thing it is not, or a claimed model that departs from what the model actually IS, without any documentation as to exactly what was modified! Its not possible to apply one's brain to evaluating the recommendations made by any model if one doesn't know what has been done to it.

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This is exactly what I mean by "know what you are doing". Clueless newbies will search for a published program/answer that they can hold someone else responsible for. You can only know through experience. Get experience, then do. You will see.

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Originally Posted by Genesis

I understand Chip, .

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Thank you….
I appreciate what you said.

Your generosity was very gracious.

Andrew

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Originally Posted by Genesis

Somehow I need to be able to cut backup tables that MATCH the computer's profile! These guys have to understand that... no?

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Q: Is their going to be a way to cut back-up / bail-out tables for the VPM VR3?
A: yes in diveplan mode

Q: Is VPM going to be incorporated into ProPlanner or will you have a VPM simulator / dive planner for the VR3? It would be nice to have a way to create backup table that MATCH the computer’s profile.
A: yes proplanner will be vpm as well. tables will never exactly match a variable DC profile but they will be close. We are testing VPM for safety issues now.

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Originally Posted by DeWayne

Ask him if they are close to having a date set for implementation. It will be very interesting to see what is finally released.

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Q: Do you have a target release date for the VPM VR3?
A: Summer

Cool - good answers thus far... now the wait begins :-D

Chip, thanks for the detailed postings. Your attention to detail in a public forum is noted and appreciated.

Thanks for getting that info and passing it along Chip 8)