Do decompression divers use computers?

[Meng_Tze]

I use a DiveRite Duo for deco dives on Nitrox....

These little things are rock solid! Simple and can be used as BT later on. A very good start.

Whatever you get, be sure you know how to run a dive based on a BT and a table. This way if you ever end up in situation where a computer can't get you out, they will. .... (or in some of my cases, the table was a lot faster than my VR3...so I had options)

 

[Chatterton]

I have found the shortcming for the Duo is that if you violate the computer, it locks you out for 48 hours even for a minor violation. It is good for what it is, an inexpensive two gas computer and a gauge.

I have never liked the VR3 deep stops, and recent research indicates deep stops are not working. The VPM tables for the VR3 made it better. The new VRx is better still and enables you to change the Gradient Factors, and is much better than VR3.

The Shearwater is a great little (not that little) computer that is very intuitive and you can pretty much use it without reading the manual (although I am not recommending this). Two buttons, Menu & Select (easy), it has big well lit numbers, and lots of features including the ability to change Gradient Factors.

The HSE Explorer does not work, period. It is crap.

Most improtant thing to me: The computer can be upgraded, as what we know about diving and decompression changes.

CHeers

JC

 

[Hoyden]

I have never liked the VR3 deep stops, and recent research indicates deep stops are not working.

Will you supply references to this new research?

Thanks,

Jackie

 

[dab]

Most improtant thing to me: It can be upgraded as what we know about diving and decompression changes.
JC

This is what is so nice about the X-1. You are buying the hardware and then purchase the software separately. As advancements are made new software can be loaded. It is a well made computer and easy to use. The only downside I see is Liquivision is a small company and relatively new to the market. I've been using two of them for almost a year now and love them. They are rock solid. I've also used the VR3 (with VPM algo) and Cochran.

 

[jscott099]

I was able to get through TDI Advanced Nitrox and Deco Procedures using V-Planner and my Suunto Vytec (multi-gas). I have V-Planner on a Windows Mobile device so I carry it right on the dive boat and work out the run plan and put it on my slate. The Vytec serves as a backup although it tends to demand somewhat longer deco stop at 15 ft on repetitive dives (the hang bar is at 15 ft on most NC coastal dive boats). For the amount of deco diving I do, this arrangement is sufficient and allows me to keep using the Vytec for recreational and cave diving as well. I understand however that it is not ideal for serious use however. I have been eyeballing the Liquivision with envy.

 

[Blackwood]

I was able to get through Advanced Nitrox and Deco Procedures and Trimix using a single gas computer in gauge mode.



The answer is: some do, others don't, but everyone has a method to develop decompression schedules. That said, I would venture a guess that most use desktop software and multi-gas computer in combination.

 

[battles2a5]

There are definitely two schools of thought on this; the purists who say you should only use a BT and tables, and the computer crowd. I'm definitely in the computer crowd. IMO, there are a lot more drawbacks to NOT using a computer than there are to using one.

If you are diving a known site, with a square profile, then tables and timers are fine. Anywhere else, there is a significant advantage to be gained by using a computer.

It is great to learn on tables, however. Kind of like learning basic mathematics when you were a kid, putting together your own tables, calculating your own gas plan, doing all of those things builds some very necessary fundamental skills that everyone should do. Once you understand the basics, just like you did in school, you buy the damn calculator.

This is not to say that tables become less important when you use a computer. Cutting your tables is still a necessary component of the dive plan; primarily for gas, CNS, and contingency planning. I'll run a plan, extended plan which varies based on the dive plan (+5min/5ft for deep dives, +10/+10 for nitrox), max gas, and bail-out (1/2 BT) plus lost gas scenarios. I'll have all of this information on my slate in case my computer buys the farm, but this also helps me understand what my gas plan and required gas for the dive.

I dive a Shearwater Pursuit, backed up by tables (usually cut on V-planner or Free Planner). Running 20/90 gradients will put out roughly the same plan as V-Planner @ +3. The shape is a little different but RT's, gas, and CNS is as close as you can get. I would use Free Planner (same algo as the Pursuit) but I hate having to convert liters into CF and it's not as user friendly as V-planner.

 

[DA Aquamaster]

I guess I do it differently than the computer as primary crowd. I cut tables using Palm VPM or D-Plan, verify the gas planning and then transfer the deco schedules, contingency and lost gas deco schedules to a slate. I use a computer but it is basically back up to the tables.

Personally, I think if you start relying on the computer, you will eventually screw up and get your self into a deco schedule your gas can't handle, with open circuit at least. I also wonder about some rebreather dives and bailout gas that could be shaky at best with a failure just before the planned ascent.

I have been using an EMC-20H and am still working the bugs out in terms of conservatism settings that are a decent match for my planned deco profiles. One diver I know uses hers as a means to get herself out of the water in minimum time if something goes wrong, and in general I agree with the idea of using a computer to get you to the surface as soon as safely possible in an abort situation, but I still want a similarly conservative deco schedule and settings that are compatible with the other computers in use on the team.

So far the EMC-20H has struck me as being very liberal, and I have mine set at 65% conservatism to stay in the same ballpark as my buddy's VR3. The EMC-20H is also a PITA to significantly reprogram unless you bring along a laptop.

If a diver is only using a computer, they need to have redundancy (ie: two of them) and they still need to be vigilant about the gas planning. Personally I will continue to cut tables and use my bottom timer and tables as primary with the computer being the backup and abort option.

A three gas computer is needed for trimix, but many technical divers and in particular N FL cave divers can go a long way with just a nitrox computer on longer dives to 100-130 ft, and I think the Nitek Duo is a good choice that won't break the bank and can also be used as a bottom timer in gauge mode later.

 

[Diver0001]

I guess I do it differently than the computer as primary crowd. I cut tables using Palm VPM or D-Plan, verify the gas planning and then transfer the deco schedules, contingency and lost gas deco schedules to a slate. I use a computer but it is basically back up to the tables.

That's exactly what I do but I use Vplanner.

R..

 

[battles2a5]

Personally, I think if you start relying on the computer, you will eventually screw up and get your self into a deco schedule your gas can't handle, with open circuit at least. I also wonder about some rebreather dives and bailout gas that could be shaky at best with a failure just before the planned ascent.

I think this is a key point. I also hear this as an argument against using a computer quite regularly. You simply cannot become complacent with computers. Every one of my technical dives, without exception, starts out on a slate. I run the profiles, choose my gases, determine what I need to carry and get all of the information squared away before think about getting in the water. The dive can go on at this point without the computer if need be. Then I program the gases in the computer and do the dive. I will never be dependent on the computer, so I have a tough time with the argument against them. To me, it's akin to not using a power inflator because I might get complacent and forget how to manually inflate. It's just another tool in your bag which can be instrumental in getting you out of the water as quick as possible in an emergency, but also introduces a lot of flexibility into your dive plan to account for any of several variables that will vary from your originally intended plan.