Air/Nitrox?

[DA Aquamaster]

A computer generally speaking is designed with multilevel diving in mind and, like multilevel tables such as the PADI wheel, uses NDL's that are a bit more conservative than a table.

So yes, if you are doing a square profile, you can get a few more minutes out of a table than a computer as the computer will be more conservative in that situation. But if you are doing a multilevel dive, you will get more time out of the computer than you would having to be more conservative (ie: next greatest depth and time, etc) in using your tables. Interestingly, I have also found that the algorithm in my current computer allows me more time at depths below 140 feet than the US Navy tables, so the presumed advantage of tables on square profiles is not always a sure thing.

In my case I was fine with tables and eventually with a PADI wheel when I started doing multilevel dives, but I found a computer made a whole lot more sense when I started doing high altitude dives. Correcting for the altitude in addition to the multilevel planning is just a bit too much. And trying to do the math on the fly at 130 feet on air is a really bad idea. A computer just makes a lot more sense.

I will plan the dive and develop a worst case contingency plan for deco in the event the computer fails during the dive, but I will follow the advice of the computer during the dive as it is franlky very good at figuring the the N2 and O2 obligations and it lets me concentrate on other things during the dive.

 

[Scubakevdm]

DA AQUAMASTER! You Da' man. I agree that this is truth.

 

[iflyprops]

Yes you can use an air computer on nitrox...but you will be diving air profiles! SO unless you would really like that extra margin of safety get the computer. Also if you have an air computer make sure and pay strict attention to your MOD....although you need to pay attention to that anyway!

 

[cornfed]

I just know that I have locked out my vyper and also a buddies computer by doing deep stops even within NDL. The computer doesn't like it.

Your computer crapped out while within the NDL?

 

[cornfed]

Rather than merely stating that you can stay longer, please help those of us that may not understand why you think this, perhaps by helping us understand the method you use for calculating NDL and stop info.

A specific example would be great...

I'm interested....

The method Laser is talking about it based on average depth. If you have some software like Suunto's Dive Manager to play with you can get a general idea of how it works. SDM will display the saturation values of different compartments at various points through out the dive. Now take two dives, one that is a multi-level dive and the second which has the same average depth as the first. If you compare the final compartment saturation values you'll notice that they are very similar. This is a very watered down version of the theory behind what laser is suggesting.

 

[DA Aquamaster]

I appreciate the offer. I just know that I have locked out my vyper and also a buddies computer by doing deep stops even within NDL. The computer doesn't like it.
You on Splashdown? You know Mike Gray?

I have never had that problem with a computer locking out on a deep stop before. Nearly every computer on the planet will accomodate at least some excursion from the NDL' and get you through the required deco. Many computers state they are not designed for intentional deco, but they do a good job of getting you out of trouble on an unintntional deco situation. And a deep stop of say 70 ft on a 140 ft dive is no different than just staying at 70 ft on what amounts to a multilevel dive.

I am frankly having a little trouble giving your statement a lot of credibility. I do deep stops all the time as well as quite a bit of deco diving with an added deep stop and I have never locked up any of the computers I have used including a couple from Scubapro, two from Aqualung and my current Genesis Wisdom.

 

[5615mike]

I'm sorry, but I have to disagree. A computer lets you spend alot more time diving than the tables do, safely........... Nitrox is safer ( up to M.O.D.) than air and allows you to spend way more time underwater. ..................

Scuba

Since your going to make such a BROAD statement like that.......I would be interesting knowing your thought process. Looking forward to your answer.

 

[Scubakevdm]

Scuba

Since your going to make such a BROAD statement like that.......I would be interesting knowing your thought process. Looking forward to your answer.

Okay, here we go. There are two parts to the quote you have included in your post, and they talk about two different things... so I'll break up my response into two different though processes.
1) Multi-level credit.
2) O2 displaces N2, less N2 is good.

 

[fgray1]

Okay, here we go. There are two parts to the quote you have included in your post, and they talk about two different things... so I'll break up my response into two different though processes.
1) Multi-level credit.
2) O2 displaces N2, less N2 is good.

Just thought I'd let you know I get it.
Fred

 

[Laser]

I have never locked up any of the computers I have used including a couple from Scubapro, two from Aqualung and my current Genesis Wisdom.

I believe it was on the 4th dive of the day when it cut me short and locked up, but I'd have to look through my log book. vplanner and tables ended up giving more time on that last dive of the day. I guess it didn't " lock-up " per-say, but wanted a ridiculous amount of time @ 20ft and when I didn't comply, it did.