Shearwater Teric wish list

[Jay]

Hi I have been diving an Oceanic AI computer for about 18 years/1850 dives and can confidently say that the ATR calculation for no stop and light deco dives is quite accurate. I have also been diving a Teric for about 9 months/a little over 100 dives and am not yet able to say the calculation is as accurate as I am used to.

Do you have an estimate of how inaccurate the Teric's GTR is?

 

[scubadada]

Do you have an estimate of how inaccurate the Teric's GTR is?

No, sorry, I can't. My Teric ownership has not been uncomplicated. I had my 1st Teric for about 100 dives before the screen went black. It was not entirely trouble free before that as 10-20% of the time it would not calculate the SAC of a dive despite having the beginning and end pressures. It was with this computer that I noticed that the Teric GTR generally ran shorter than my Oceanic VT3 ATR. I have used the VT3 for almost 10 years/1450 dives. I never recorded or took photos of the difference, it seemed larger early in the dive, shorter later, but may have been about the same proportion. I was generally busy learning SurfGF and generally enjoying my diving. I sent this computer in for repair and got back the serviced computer. Unfortunately, the AI quit working on the 2nd day, they thought, a bad antenna.

This time Shearwater sent me a new unit. I have only done 6 dives on this computer. I paid only casual attention to the GTR, it's my impression that is still running shorter than my VT3. I have always run the Teric with my SS gas consumption, as small as it is, added to the end gas, in an attempt to make the two computers equal. I have a two week trip to Bonaire coming up in April and will have the opportunity, in a very relaxed atmosphere, to do a better job of quantifying the difference, if there still is one.

Sorry for the long, nonanswer

 

[Michael Jastrzebski]

All air time remaining/gas time remaining calculations are done the same way,

Frankly, I don't think @sharkguy05 gets it, I don't think he gets it that there is NO other way to compute GTR.

 

[hammet]

I would agree that is how there teric operates, which I do not agree with and is why I suggested to shearwater a RMV cal should be an option vs SAC. Maybe I did not make my point clear. If I make a plan for my dive based on the volume of gas I have this will be my limiting factor. Yes the GTR calc is based on the drop over time, but I would like it or another setting to account for the volume of gas i have left which is going to vary from tank to tank based on it operating specs. All I am saying is that with a RMV readout it will limit the math I have to do under water and a GTR that does account for the volume of gas I have makes for simple math. Sure if your at 100ft and you stay there and your sac is 30psi/min and you have 300psi in your tank and the your reserve is 0psi then you have 10 minutes at that depth which is how the teric operates. A computer to that has something similar to the features I would like to see on the teric for gas calculations is the Atomic cobalt. Yes their GTR is calculated by pressure drop over time also.

@sharkguy05
I often use my teric to monitor my breathing rate. I look at my SAC rate just after decent and hitting my depth and after doing any activity such as grabbing a lobster which would cause my breathing rate to increase. I average an RMV of about .45 cf/min but I know if I'm keeping that number below .50cf/min, I'll have enough air for what I expect to do on any particular dive I plan.

I also use two different types of tanks: AL80s in the carribbean and HP100s in Florida. So here's how I track my breathing rate with the Teric SAC display:

An AL80 has 77.4cf of air at a working pressure of 3000psi. Therefore, an RMV of .50cf/min would have a corresponding SAC rate of [(3000psi/77.4cf)*(.50cf/min)] = 19 psi/min.

An HP100 has 100cf of air at a working pressure of 3442psi. Therefore, an RMV of .50cf/min would have a corresponding SAC rate of [(3442psi/100cf)*(.50cf/min)] = 17 psi/min.

So, depending on which tank I'm using, I simply make sure my breathing rate is under either 19psi/min or 17psi/min.