computers and redundancy

[Prepare]

hi guys i have a few questions.

whats the norm for tech diving with computers

1) do you dive with the computer and follow its deco instructions AND have backup tables. How close are the run times between computer algorithms such as uwatec/suuntos and deco programs such as v planner?

2) do you dive with the computer in gauge mode and do deco reqs from tables produced before the dive?

when most of you do tech/deco dives and DONT have a regular partner, what happens if your buddys computer or dive tables have different stop req or hes using a different deco mix. do you seperate on the upline for deco or do you go by the most conservative deco reqs?

and which computer would you guys recommend. Smartcom/Cobra. i know there are lots of threads on this so just looking for personally pref.

ive only done 30 dives but im planning on getting into some deeper/tech diving later on so would like to buy the right gear now.

thanks guys

 

[fdog]

Prepare:

As a quick answer all my deco dives are well planned affairs to particular depths and times. I choose to use cut tables from VPlanner and a bottomtimer. I can't say about what my recreational computer says, by comparison to VPlanner, because my recreational computer hasn't been there.

I do dive a computer for recreational diving, however these dives are with recreational equipment, at typical recreational profiles, and never become overhead-restricted by deco. These meandering, multi-level dives don't go into deco because I don't let them.

Although I haven't yet dove deliberate deco with someone who used a "tech computer" (such as the VR3 or HS Explorer), this is something that would be covered in our pre-dive brief. If for some reason my cut tables indicated that I should get out of the water first, I would hang with my buddy, as I have never abandoned someone in the water and don't intend to start.

Chatting with those who have used the Suuntos, it appears these impose a significant time penalty (get you out of the water much later) than VPlanner, although I have not seen this personally.

All the best, James

 

[Diver0001]

hi guys i have a few questions.

whats the norm for tech diving with computers

1) do you dive with the computer and follow its deco instructions AND have backup tables. How close are the run times between computer algorithms such as uwatec/suuntos and deco programs such as v planner?

2) do you dive with the computer in gauge mode and do deco reqs from tables produced before the dive?

when most of you do tech/deco dives and DONT have a regular partner, what happens if your buddys computer or dive tables have different stop req or hes using a different deco mix. do you seperate on the upline for deco or do you go by the most conservative deco reqs?

and which computer would you guys recommend. Smartcom/Cobra. i know there are lots of threads on this so just looking for personally pref.

ive only done 30 dives but im planning on getting into some deeper/tech diving later on so would like to buy the right gear now.

thanks guys

The going thinking in the main stream is to plan the dive on tables and take both tables and a computer as backup. The computer is generally seen as essential for backup but really a last resort. As the sophistication of computers catches up with the best practices in deco theory then this may change but we're not there yet.

DIR flies a little bit different course on this. The going thinking in DIR circles is that the computer is unnecessary. The reason being that DIR/GUE has developed (actually reinvented) another technique for doing on the fly deco calculations that doesn't require a computer but does have some firm requirements in terms of gasses to use and technique to be applied.

Computers common for technical nitrox are the Nitek-3, Vytec and VR2. The cobra doesn't have enough functionality for any kind of staged decompressoin diving. For full technical diving you need a VR3 or and Explorer or something along those lines.

R..

 

[The Fresh Prince]

The going thinking in the main stream is to plan the dive on tables and take both tables and a computer as backup. The computer is generally seen as essential for backup but really a last resort. As the sophistication of computers catches up with the best practices in deco theory then this may change but we're not there yet.

DIR flies a little bit different course on this. The going thinking in DIR circles is that the computer is unnecessary. The reason being that DIR/GUE has developed (actually reinvented) another technique for doing on the fly deco calculations that doesn't require a computer but does have some firm requirements in terms of gasses to use and technique to be applied.

Computers common for technical nitrox are the Nitek-3, Vytec and VR2. The cobra doesn't have enough functionality for any kind of staged decompressoin diving. For full technical diving you need a VR3 or and Explorer or something along those lines.

R..

The computer should be the one between your ears. Tables are for comparison of your planned decompression using knowledge of the curve. GUE is not the only one teaching planned gasses and decompression, but I agree with there position that a diver should be able to plan decompression in transit. I recommend that training with GUE or Instructors teaching similar decompression methods be undertaken before relying on a computer such as VR3, Explorer, etc.

 

[flw]

hi guys i have a few questions.

whats the norm for tech diving with computers

1) do you dive with the computer and follow its deco instructions AND have backup tables. How close are the run times between computer algorithms such as uwatec/suuntos and deco programs such as v planner?

2) do you dive with the computer in gauge mode and do deco reqs from tables produced before the dive?

when most of you do tech/deco dives and DONT have a regular partner, what happens if your buddys computer or dive tables have different stop req or hes using a different deco mix. do you seperate on the upline for deco or do you go by the most conservative deco reqs?

and which computer would you guys recommend. Smartcom/Cobra. i know there are lots of threads on this so just looking for personally pref.
thanks guys

It depends very much on the profile and what sort of deco you are planning on doing, and what you define as 'tech' diving.
If square profile, then up to around 45m or so, then a computer would be fine, just add in some deep stops, but have a good idea of what yor are planning on doing beforehand, and therefore what your gas requirements are. Probably a limit of around 10-15min of stops before I would start using a table instead.
On a very square profile a run time can be longer if shallow, but deeper very often will be shorter - doesn't really matter.
For dives deeper than 45m, then I'll use one of my pre-run schedules, and keep a spare in my pocket, but may 'fudge' it a bit dependant on exactly what I'm doing. I use a gauge mode computer plus a d-timer most of the time
If my buddy has a different schedule/gas to me, then we'll separate on the line, but meet back up at 6m, generally you're never very far apart anyway. The biggest difference is if I'm on zplanner and he's using a vr3, the deepest stops can be markedly different, but the total run times are generally similar.
If you want a computer that will see you through a Vyper is probably a good all round option, air integrated and multigas nitrox are expensive and probably unlikely to do what you want them to do

 

[JDostal]

If you are looking for some computer equipment that will take you through the years from rec to tec, take a look at something from DiveRite. I've been using a NitekPlus for awhile now and it's very nice. It allows you to use two gases on a dive (both nitrox mixes...no trimix capability...) and also allows you to put it into a nice gauge mode for when you progress to that point in your training. It's a nice small wrist device, so it won't take up much room and it mounts nicely - back up that with a stopwatch and a depth gauge and you've got the perfect setup for doing rec and tec...throw the Nitek into dive mode when doing rec dives, set it back to gauge mode when doing other things.

It's just my opinion

I wish I would have thought of these things when I started diving...I started out with a SmartCOM Plus - $850 brick that couldn't do half the things of my $350 NitekPlus watch.....

 

[BigJetDriver]

Hi guys, I have a few questions.

What's the norm for tech diving with computers?

1) Do you dive with the computer and follow its deco instructions AND have backup tables? How close are the run times between computer algorithms such as uwatec/suuntos and deco programs such as v planner?

2) Do you dive with the computer in gauge mode and do deco reqs from tables produced before the dive?

When most of you do tech/deco dives and DONT have a regular partner, what happens if your buddys computer or dive tables have different stop req or hes using a different deco mix. do you seperate on the upline for deco or do you go by the most conservative deco reqs?

Which computer would you guys recommend?Smartcom/Cobra? I know there are lots of threads on this so just looking for personal pref.

I've only done 30 dives but im planning on getting into some deeper/tech diving later on so would like to buy the right gear now.

thanks guys

Prepare, et al,

That is an interesting question you ask. I can can only answer it from my perspective as a mixed-gas re-breather diver and instructor.

The answer on ANY dive is, of course, to plan your dive, and dive your plan.

Your question then is: "How do I make my plan match in all three aspects---(1) Desktop (2) Wet Computer and (3) Tables?

I use the latest version of the GAP, which utilizes the full iteration of Dr. Wienke's RGBM in my desktop. This matches the full iteration of that same algorithm in my H-S Explorer wet computer. The nice thing about this mix is that NAUI has recently produced tables using the same algorithm, so all the bases are covered.

So yes, I dive with the wet computer AND have back-up tables. This is the true meaning of the word "redundancy". If Mr. Murphy strikes, and I lose my deco based on real-time PPO2, I can at least go my timer, depth gauge, and tables using the same algorithm. While it is, by its very nature, not as precise, it will serve the purpose of returning me to the surface safely.

As for your second question, I am not about to cripple my very effective wet computer. That would be like pulling the circuit breakers on my aircraft's flight computers and flying around on my back-up "steam gauges". While I CAN do it this way and remain safe, it would be a very crude and imprecise way of doing things. I know the guys from the "Amish Diving Society" like to do it that way, but even though I am a member of the Historical Diving Society, I don't want to become a diving history "re-enactor". (Except, of course, for such things as the "Dive The Five" experience, which is a real hoot!)

You actually answered your third question yourself. If your partner, or your team members are running a more conservative program, it costs you nothing (except a few minutes of your time) to wait. You should NEVER leave your partner.

As for the Cobra, in my opinion it is a good, solid computer, and does have (AFAIK) a limited form of RGBM.

You sound as if you are looking ahead, and planning for a long and enjoyable diving career. Just remember the conundrum about how one eats an elephant (i.e. one bite at a time). Get good training for each phase, and get enough experience in each phase to feel comfortable with what you are doing before going on to the next phase.

I hope you will have a lot of very happy and safe diving, both bubble and no-bubble type.

Cheers! :anakinpod