What computer would you recommend for Tek Diving?

[kenseal]

I've used a Dive Rite He (Helium capable) computer for my tech diving since June of 2005 and it's worked great for me but I never did pursue taking the trimix class. I'm going to be putting it up for sale here soon to get a hoseless or air integrated computer. If you're interested I can send you pictures and let you have it for $600 instead of the $1,000 you would have to spend for any other kind of multigas computer. It can switch up to seven gases and also be used in gauge mode. I will let you know that the one thing I don't like about it (and others) is the font size is kind of small because they have to get a lot of information on the screen. I'm in my mid-fifties now and my eyesight is not as good as it used to be. That's that main reason I want to get a larger screened computer.
Ken Seal

 

[DwayneJ]

Can I ask you to explain your comment........
I just made sure the computer cleared the deco obligation before I surfaced.......no issues..... M

Suunto's are only recreational computers. The deco obligations they throw you are likely to be more conservative than if using tables/software/full deco capable computer. Their "deco" capability will get you out of the water. Although your Suunto does not "lock up", many rec computers do. For all the talk that Suunto publishes about deco capability, they need manual backup via tables which requires some alignment between software/written tables and the computer itself. Additionally, as a trained deco tech diver, using only one gas mixture (air or nitrox) for your deco diving is a major limitation.

That being said, I use a VR3-HD and my buddy uses a Suunto. My VR3 settings are not aggressive but my buddy reaches NDL limits sooner than I do. When I'm down to 7-5 mins of NDL time, my buddy will be at NDL limits. Of course he is looking at bars on a bar scale and I'm counting down minutes. I love my VR3.

D

 

[Jorgy]

Still a little confused, the OP stated "my old computer would work, but it locks for 2 days if deco is reached"......I was just not aware of any modern rec computers that would "lock" unless the deco obligation was not met.......

I agree, the Suunto (or other rec computers) deco is probably much longer than required (an aside - that would be an interesting comparison).....the OP must have been using tables or another computer to get out of the water before his computer cleared, therefore locking it up......I guess.....

Of course, I would just leave the computer hanging at 15 feet until it cleared, rather than lock it up, if I had the gas it would be on my arm, if not it would be tied to the line or on the end of my spool.....

My Gekko's and Vyper's count down NDL in minutes, I don't even see the cumulative bottom time bar, I leave it in Nitrox mode all the time, just set to 21% O2 when diving air and it shows OLF instead of CBT.

M

 

[wedivebc]

Still a little confused, the OP stated "my old computer would work, but it locks for 2 days if deco is reached"......I was just not aware of any modern rec computers that would "lock" unless the deco obligation was not met.......

Yes but when using higher O2 mixes to accelerate off-gassing you need a computer that is aware you have changed breathing gas and can deal with the higher O2 mix. Most rec dive computers will just lock up if the diver follows tables using accelerated deco profiles.

 

[Jorgy]

Good point.......in your scenario, my Vyper would be hanging at 15 feet.......

While I would be safely out of the water..........
M

 

[ssturges]

That being said, I use a VR3-HD and my buddy uses a Suunto. My VR3 settings are not aggressive but my buddy reaches NDL limits sooner than I do. When I'm down to 7-5 mins of NDL time, my buddy will be at NDL limits. Of course he is looking at bars on a bar scale and I'm counting down minutes. I love my VR3.

D

Your VR3 might be more aggressive than you think, see the following link

Message from the Head Divemaster

Quote from the link:
VR3, both generations, by Delta-P
"We have noticed a trend with the VR3 Dive Computer that I feel needs to be brought to our customers attention. Statistically over the past year we had an alarming number of divers show potential signs of DCS when diving with the VR3. In none of the incidents reported to us by our customers was there an error on the part of the diver. Due to the nature of the diving we carry out on Bikini please ensure you are fully familiar with the variable settings on this computer. I strongly recommend you completely understand why and how to program the device to ensure a strong safety margin when diving at Bikini prior to your departure. (This may just be an unpleasant coincidence, however I feel it is important to relay this trend to potential customers.)" - Jim Akroyd, Head Divemaster, Bikini Atoll Divers

 

[ianr33]

That quote is from a company that was in the business of renting out DiveRite computers.

Everything I have ever heard about VR3's points to them being very conservative. On my deco course the instructor tied his off to a line at 10 ft to get it to clear.

Last weekend I was supporting a couple of buddies. One on tables,other on a VR3. The VR3 gave an extra 20 minutes or so deco.

 

[chachee99]

Can I ask you to explain your comment........

"but it locks for 2 days if deco is reached"

Thanks......

I have gone deco 4 times on my Suunto, once by accident with me even realizing, I only saw the deco when I downloaded the profile, the other times I knew I was in deco. I just made sure the computer cleared the deco obligation before I surfaced.......no issues.....

M

I am using a Cressi-Sub EDY dive computer. it is a great computer for recreational diving, but it is not very handy for TEK. Basically here is what happened. I did my first decodive at 45 meters. As expect, the watch started beeping like crazy when I came close to the NDL and really started beeping and flashing like crazy when I went into DECO. Again, I expect this. For the first dive it everything worked like a charm. No problem. Later that day we did another deco dive. My computer was still flashing DECO and I could not switch it to gage mode. I was hoping it would still be able to display the depth and time of the second dive. However, as we decended into the water I noticed that the Cressi would not register anything. So rather than abort the dive, I just used my instructors Uwatec bottom timer instead and followed the dive plan on my arm slate. He used the VR3.

When I surfaced i noticed i noticed that the Cressi would continue to flash deco. It would not allow me to go into any other settings. It would only display the current time of the day if i pressed the mode button. The computer was locked like this for two days.

Once the computer was unlocked. I changed it to gage mode and used it as a bottom timer. I kept using the dive shops Uwatec bottom timer along with the gage mode. I kept them both on the same arm and noticed that the depth on the Cressi read around a meter less than that on the Uwatec. The dive time on the Cressi seemed to be off about 40 seconds too. My instructor said that probably my computer was callbrated for fresh water instead of sea water. However, I checked the manual and it stated that the Cressi- EDY is callibrated for salt water. We were diving at the same depth His VR3 matched the depth on the Uwatec.

So basically the Cressi EDY isn't a very useful computer for tek diving. Not even in gage mode because it gives a different reading than a bottom timer.

 

[DwayneJ]

Your VR3 might be more aggressive than you think, see the following link

Thanks but I think its about understanding the full capabilities of the computer and I have a high degree of confidence in the manual/software tables backed up/confirmed by the VR3's tables and actions.

For multiple gases, you have the option to enter a different PPO2 value and associated maximum operating depth. The computer has a general safe setting which increases its conservatism.

I'm happy with it.

 

[Jorgy]

Thanks for the details........

It is strange, on your first dive you cleared the deco obligation on the computer yet it still locked out on the second dive........

I wonder if Cressi wants you out of the water for an extended period of time after any deco dive even if you fully clear the deco obligation on the dive........perhaps like a "no-fly" count down..........

Very interesting.........

I will go back and look at my deco dives and see if there is anything I can see from my profiles........

I do agree with everyone, that a rec computer is not the answer for technical diving, just trying to better understand dive computers in general..........

M