Worth it to get a N2ition 3 for deco diving?

[khacken]

I am thinking about purchasing a N2ition 3 for my full cave cert class. All of my deco dives have been on tables, with my Oceanic VT Pro in gauge mode. But I was considering getting a N2ition 3 for my primary computer, then using the VT Pro as a backup computer.

I realize the VT Pro does not do gas switching, so I would end up with longer deco obligations in the event of a failure on the N2ition. Also, I would go to O2 at 20ft, which should give me a margin a safety. Also, I know the VT Pro is not intended to be used for deco diving, so this may be a really really bad idea.

Another option would be to dive the N2ition 3 as primary, and cut tables with vplanner as backup. That would require more work, but if that is the only safe way, I will do it.

Finally, I could just save the money and stick with the tables and use the VT Pro in gauge mode.

I would really prefer option one, but then I really really prefer to stay alive.

 

[ucfdiver]

I used a bottom timer only in full cave....also we used o2 for deco in class, not just safety margin.

I would really prefer option one, but then I really really prefer to stay alive.

I'm sure lots of us would be dead or severely bent if avg depth+BT didn't work, it's pretty well proven.

 

[syntaxerrorsix]

Check out Cochran 20H, does 3He 3O2, auto gas switching, adjustable conservative levels plus a bottom timer



The EMC-20H is the simplest of dive computers to use and understand, even for beginning divers. It is ready-to-use straight out of the box. Merely understand the large easy-to-read display and audible warnings.

The intelligence built into the EMC-20H manages everything else. It automatically, seamlessly, and constantly adapts to your personal diving style, water temperature, salt/fresh water, ascent rates, and altitude . It even has a built in 'Flight Data Recorder' that records changes in altitude during your flight to and from the dive destination. (Eighteen percent of the DCI incidences occurred during or immediately after a Post-dive change of altitude.)

Multi-blend configuration features Cochran's patented gas blend switching.

Available configured for:
Air Only


One Mix Nitrox - 1 FO2


Two Mix Nitrox - 2 FO2
One Mix Nitrox Switchable to One PO2 - 1 FO2 / 1 PO2
Two Mix Nitrox Switchable to Two PO2 - 2 FO2 / 2 PO2


One Mix Nitrox + Helium (One Mix Trimix or Heliox) - 1 FO2 + He


Three Mix Nitrox + Helium (Three Mix Trimix or Heliox ) - 3 FO2 + He


One Mix Nitrox + Helium (One Mix Trimix or Heliox) Switchable to One PO2 + Helium (Trimix Diluent) - 1 FO2 / 1 PO2 + He
Three Mix Nitrox + Helium (Three Mix Trimix or Heliox) Switchable to Two PO2 + Helium (Trimix Diluent) - 3 FO2 / 2 PO2 + He
Choice of Wrist Unit Mounting Options
Module Only Hose Mount
Wrist Mount - Standard Twin Console
Retractor Triple Console
Retractor with Compass
Choice of Standard Red Backlight or Optional Yellow
Choice of Wrist Unit Case Color:
Navy Seal Black - Standard Bright Sky Blue
Deep Sea Blue Nitrox Green
Battleship Gray Sunshine Yellow
Titanium Color
Choice of Dive Profile Memory (at One-Second Sampling):
180 Dive Hours - Standard
360 Dive Hours
725 Dive Hours
1450 Dive Hours
Interdive Profiling (Records Events Between Dives such as Altitude Changes)
Uses N Size Alkaline Batteries (User Changeable)
Battery Life is Over 1000 Dive Hours (Depending on Taclite Usage)
Extended Range 20 Compartment Algorithm
Maximum Depth Over 410 feet
Decompression Ceilings to 410 feet
No Lock Out
Real Time NDC and Deco Times Based on Breathing Mix Currently Being Used
Real Time CNS and OTU Oxygen Toxicity Calculations
Decompression Times and Ceilings Based on FO2 of All Mixes
Decompression Times Account for Ascent Rate
Automatic Altitude Acclimatization up to 16,000 Feet

Environmental Compensation for:
Water Temperature
Altitude
Microbubbles
User Added Conservatism
Previous Dive Profiles
Salt Water / Fresh Water
Predive Airplane Flights
Postdive Airplane Flights
Work Load
No Hands Gas Blend Switching

 

[khacken]

I used a bottom timer only in full cave....also we used o2 for deco in class, not just safety margin.

I'm sure lots of us would be dead or severely bent if avg depth+BT didn't work, it's pretty well proven.

so you take avg depth + BT as opposed to max depth + BT time?

 

[ucfdiver]

so you take avg depth + BT as opposed to max depth + BT time?

Around that. If there's a sharp drop in depth I'll pad it a bit, if it's a fairly steady sloping profile, I'll go with the average.

Here's a good article on it-
DIR-diver.com - Average depth for deco?

I had a buddy diving a vr3 which cleared a few minutes faster than my tables. He waited on me to clear, and still got bent, even though we followed the same ascent profile. I was fine, no skin bends, fatigue, or any subclinical sign as we drove to the hospital, while he ended up needing a table extension in the chamber. It's not an exact science anyways, so I'm not all that concerned missing/adding a few minutes here or there. I think that staying hydrated, in decent physical shape, and well rested is more important than following an exact profile anyways.

 

[Tassie_Rohan]

I've been using a N2ition 3 recently.

As my deco dives use RGBM models I dive using tables and a bottom timer - the modified bulhman the N2ition uses leads to much longer shallow stops, less deep stops and so has a completely different dive profile.

I leave the N2ition on (rather than in a gauge mode) as a back up timer and just to see how it reacts when compared to my tables. I guess I could use it as a 'bail out to bulhman' backup if I somehow lost my and my buddies tables - but I can't see that happening anytime soon.

Cheers,
Rohan.