Cochran GEMINI
- Thread starter zyxomma
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Blahh! Personal opinion only...
Personally I would recommend the commander because cochran has a pretty good upgrade policy and you can always have features added..zyxomma:
Mark Vlahos
Contributor
Hi,zyxomma:
I dive a Cochran Gemini with the 3 FO2 software.
I am pleased with the computer and with Cochran in general. I have had one minor problem with the computer out of the water, and it was dealt with promptly by Cochran. I have never had any problems with the computer in the water. The computer is a little on the expensive side.
If you use the computer without adding any of the "user added conservatism" it is extremely liberal at shallow depths. It becomes more conservative the deeper you go. The no deco limits at about 80 to 90 feet are similar to PADI no deco limits, and deeper it is more conservative than PADI limits.
There are many adjustments that you can make to the computer that will affect how it reacts to different situations, most of these are only available to you with the Analyst Software for your PC. Getting the Analyst software is a good idea and you should probably include it in your total budget from the outset. I believe they will be releasing version 4 of this software very soon, so if you are planning a purchase make sure that you have the most current version of the software, or a free upgrade to the new version when it is released.
If you have done your research you should be familiar with the many ways to modify the way the computer reacts. Following is a partial list of the personal adjustments you can make...
Variable ascent rate from 20 feet per minute to 60 feet per minute, or a fixed but proportional ascent rate of 60 fpm below 60 feet and 30 fpm above 30 feet.
You can have the computer add conservatism to compensate for cold water, or you can turn this off (using a dry suit is an example of when you would want this off).
You can have the computer add conservatism to compensate for increased work load.
The computer will adjust its calculations for subsequent dives if you ascend too fast.
The computer will automatically compensate for altitude diving.
The computer will make adjustments based on recent altitude changes you have made prior to or just after a dive (you need to carry the computer with you as you change altitude for it to be able to make these compensations).
The computer can make adjustments for deep dives that follow shallow dives.
The computer will adjust for the differing depth readings between salt and fresh water so it will be accurate in both.
You can add your own additional level of conservatism independently of the above considerations. The method used is for each number you add (from 0 to 50) the computer will base its nitrogen loading calculations on that percentage deeper depth than you actually went. For example if you set the user added conservatism to "10" and make a dive to 50 feet the computer will make its nitrogen loading calculations as if you had been at 55 feet not 50, a 10% difference. If you had made a dive to 100 feet the computer would make its nitrogen calculations as if you had been to 110 feet, again a 10% difference. The computer does not make any alteration in its computations for oxygen toxicity based on your user added conservatism, in each of the dives I indicated above all oxygen calculations would be based on your actual depth, NOT an artificially deeper depth.
The Gemini is air integrated and the Commander is not. The Commander is noticably less expensive. The Commander is not available with 3 Nitrox gasses, this was a motivating factor for my decision to get the Gemini.
The Gemini and Commander also both have user replacable batteries. The Commander and the wrist unit for the Gemini both take "N" size batteries, and the Gemini tank unit takes "AA" size batteries. These batteries can be replaced in the middle of a dive vacation without losing current dive profiles, you could safely replace the batteries between dives during a surface interval and the computer would accurately continue to track your nitrogen loading and oxygen toxicity factors for the next dive. This of course assumes that you have fresh batteries on hand and you replace the batteries in a timely manner.
The Gemini computer is located in the tank unit and this computer makes all of your calculations, in short this is the dive computer - not the thing on your wrist! This is different than every other hoseless dive computer I have ever seen. One nice thing about this technology is you can use multiple wrist units to display the data from your computer. I have a Monitor wrist unit, this is exactly as it sounds, the monitor wrist unit is simply a display for the tank unit, it makes no onboard calculations itself. I also have an Intelligent wrist unit. This differs from the monitor in many ways, when the system in functioning normally the intelligent wrist unit acts exactly as the monitor, that is it simply is a display for the tank unit. If the tank unit should fail, or the communication link should fail the intelligent wrist unit will take over the calculations and become a non-air integrated stand alone wrist computer. The intelligent wrist unit does have all of the necessary hardware to make all of its own calculations and function independently from the tank unit.
One possible use for an additional monitor wrist unit was related to me by a friend, A husband and wife team enjoyed diving together, he was a photographer and tended to get very involved in his hobby, his wife acted as a safety, she would dive near by and monitor both his and her dives. If he became distracted and failed to notice that it was time to ascend, she could simply monitor his gas supply and bottom time on her extra wrist unit. Of course he should be paying attention to it himself but for this husband and wife team, they both liked the flexibility the system gave them.
Cochran has had troubles in the past and some of their computers were not reliable, I feel that they have put these problems behind them. You should be aware that these problems have existed, do a search for "Cochran" on this board any you will see many complaints in the past regarding the hardware, and the customer service policies. You will also see some praise. The choice is yours to make. I do not work for Cochran, I am simply a satisfied customer. All of the above information is either from my personal experience diving the computer, or the manual and other printed or web related materials, or from conversations with others who use Cochran computers; there may be some mistakes, please do your own original research.
My Gemini is as follows...
Tank Unit with 3 FO2 software with standard memory.
Yellow Intelligent Wrist Unit with Red Tac-Lite.
Yellow Monitor Wrist Unit with Yellow Tac-Lite.
Standard SPG as backup if the tank unit should fail. (never needed, but always monitored)
I have the different color lights as a reminder of the differences in the two wrist units.
Mark Vlahos
Mark Vlahos:
Wow, well thanks for all that information. It was helpfull.
The one thing I was wondering about was the second wrist mount you have. Could you expand on that a bit more? I understood some of it like when you were talking about the husband and wife, but how you go about using it I was a little bit confused. I think it is mainly because the Cochran has the seperate computer that attaches to the tank.
Anyways, I am a new diver looking at all the different equipement and I know I want a hoseless wrist mount computer and I have narroed it down to the Cochran Gemini and the Aeris Elite.
And so far from what I have found they are both pretty good computer with difference features to them.
Mark Vlahos
Contributor
Hi,zyxomma:
The "Monitor Wrist Unit" is a display only for the tank unit.
The "Inteligent Wrist Unit" is both a display for the tank unit (during normal operation). AND in the event of tank unit failure it will become a stand alone dive computer. If the tank unit should fail during a dive the Inteligent wrist unit will continue to make calculations based on all previous dives and the current dive you are in. The only information missing is due to the reality that the wrist unit is not air integrated so it will make no calculations relating to your breathing gas pressure. There are also some complicated issues relating to multiple breathing gas swithces that are specific to the 3 gas software. As you have indicated that you are a relatively new diver this will not apply to you so you do not need to concern yourself with the multiple gas ramifications.
I wear the Monitor wrist unit on my left wrist, and the Inteligent wrist unit on my right wrist. For normal recreational diving the monitor wrist unit only is acceptable, or the Inteligent wrist unit only is slightly better. For normal recreational diving if your computer should fail you simply end the dive by ascending to the surface as you are trained to now. For diving in more demanding environments such as planned decompression two computers are recommended for divers who choose to use a computer.
I neglected to mention in my earlier post that the Cochran computers are switchable between imperial and metric measuring systems, and the Gemini is capable of displaying your "Surface Air Consumption" rate during your dive. You can also choose to have the audible alarms silenced if you wish. I also neglected to mention that if you should violate the Gemini it will never lock you out. It will continue to provide all information and continue to calculate off gassing. This means that the Gemini does not have a separate "Gauge Mode" because the depth, time, tank pressure, ascent rate, etc... will always be displayed regardless of the fact that the computer thinks you are bent like a pretzel.
I dove with an older Aeris (750GT) computer before switching to the Gemini. I had a few problems in the water with my Aeris as well as a few problems out of the water. I believe that Aeris has solved those issues on their newer computers. I am not familiar with the particular Aeris computer you are considering.
Mark Vlahos
zyxomma:
Uwatec Pro Ultra
I had a bunch of Cochrans as rentals at my last job. I am generalizing the name as i don't know this Cochran in particular.
What a pain in the b**t to change any of the settings. To go one way use a coin, to change that use two fingers, then switch back to coin and so forth and so forth. Hopefully, the design has changed in the last year or two. Otherwise these comps are just too much of a pain to deal with on a daily basis.
Sure they have a nice big display but...
At least they give you a quarter with the computer!
My opinion only.
Mark Vlahos:
I understand the whole two computers thing know, but then again I was tried when I read your earlier message, so I may not have been comprehending it. That's for the clarification though.
You were mentioning that the Gemini had an alarm? Because some of the feature I had like on the Aeris Elite was it had an alarm that could be set to go off when you were running out of dive time or air. It had a light you could turn on to read the display. You can turn it on outside the water to access the information. And a few other things like that. Nothing to major. If you interested the information can be found at http://www.diveaeris.com/p_computers_elite_features.html.
I was wondering if you could tell me what the difference is between the software. What I mean is I had read there is a professional version and a non. What is the difference between the two.
Thanks
Nick
Mike Veitch:
From what I have seen I think the computer is setup the same way, but you can change alot of the setting by hooking it up to a computer. Or at least that is what I have been told.
So is that the only thing you didn't like about the computer? The interface that is? How was it for diving. Any problems?
Nick
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