Cochran dive computers... good or bad?
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february29th
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Here are problems about cochran.
Cochran Computers on Bikini Atoll
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I am looking for computer:
Price about 500$
Will not "lockout" after a missed stop or ascent rate violation.
Nitrox %50
Fresh or salt water
Automatic altitude
Buhlman ZH L16
High Accuracy "depth ,altitude"
User replaceble battery
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Diverite nitek duo (good)
Uwatec tec2g (lock out)
Cochran emc16( stability problem)
Another alternative...... "Off topic ???"
Cochran Computers on Bikini Atoll
---------------------
I am looking for computer:
Price about 500$
Will not "lockout" after a missed stop or ascent rate violation.
Nitrox %50
Fresh or salt water
Automatic altitude
Buhlman ZH L16
High Accuracy "depth ,altitude"
User replaceble battery
--------------------------
Diverite nitek duo (good)
Uwatec tec2g (lock out)
Cochran emc16( stability problem)
Another alternative...... "Off topic ???"
Last edited:
scubafanatic
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february29th
Registered
Which is true??
Gemini's price is not good for me.
Are niteks lock out?
Gemini's price is not good for me.
Are niteks lock out?
Exactly.
For example during a "no deco" cave dive in N FL, soon after I got my cochran, the diver I was with had a Nitek HE with 15 minutes of deco and an intital stop at 20' on the same profile where I never got below 2 minutes of NDL remaining with my Cochran set at a conservatism level of 10%.
When I talked with the Cochran rep at the DC dive show, he basically stated that unless you are really physically fit, he would personally not set it at less than 30%. 0% may have worked fine when I as 23 year old Marine, but not so much now.
Again, the only divers I know who set it at 0% are divers who run it as backup and use it as away to get to the surface in minimum with a reasonable chance of not getting bent, in the event of an emergency or if the weather goes seriously bad and the captain wants to cut down on deco time and pull the hook early.
That is coincidentally, probably very close to the underlying reasons a seal team would like it as well - avoiding any unneccesary delays under operational conditions performed under a doctrine of calculated risk.
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The sunto computers are very conservative, but the Cochran EMC-20H is at the other extreme. Again in my experience, I have to run it in the 60-70% conservatism range to keep it in the same range as the other computers I am normally in the water with (Nitek Duo, HE's etc). I would recommend you start at 50% and adjust as needed to match your dive buddy's computer.
The positive side of this is that the Cochran is one of the few computers that can be adjusted to closely match, in terms of total deco time, just about any other computer around.
And to be fair, I only have two real concerns with my EMC-20H:
1) The automatic gas switching carries with it a responsibility and an obligation to properly configure the unit before the dive, and in some cases it is almost essential that you have it connected to a laptop to do it efficiently, and it is vital if you are switching between He and Nitrox bottom mixes as I have yet to find a way to do that without a laptop. This is not a computer you can just strap on and jump in the water with.
2) It will work in areas where you do not have strict control over your profile (caves with lots of sawtooths and areas that force you above a gas switch ceiling) but your planning has to be on the money in terms of the parameters the computer uses to enable the gas switch when you exceed a certain ceiling.
Offshore, it is a great computer that can be adapted to a wide range of situations and conservatism levels.
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DA Aquamaster - Thanks for the information. I'll probably follow you advice and set to 50% and see how it compares to the computers of the other divers. Since my regular buddies use Suunto, we'll see how it matches up.
One thing I did find interesting on the last trip - even though our profiles were similar and the Cochran had more NDL time, the morning after the final dive of the trip, the No Fly time on the Cochran was longer than the Suunto by about 3 hours.
One thing I did find interesting on the last trip - even though our profiles were similar and the Cochran had more NDL time, the morning after the final dive of the trip, the No Fly time on the Cochran was longer than the Suunto by about 3 hours.
My significant other dives a Nitek Duo and a setting of 60% gets my Cochran very close to her computer (within a minute or so on dives with run times in the 1 to 2 hour range) using 32% back gas and 100% for the deco gas. I have also noted however that the Cochran seemed to get more conservative than her computer on the third deco dive of a day, so it seems to handle the offgassing differently over the long term.
Me personally I can't see the point of using a computer that can not account for lost deco gas scenarios(I'm open circuit, I won't get into it with being CCR). In the way I want to implement a computer, adaptability is the point of a computer. Right now I'm using tables and bottom timers. When I add a computer, I'll still have tables and a bottom timer but for the point of redundancy to the computer failing.......not my profile changing.
I just don't get why anyone would buy a Cochran for that exact reason but I guess it's just a difference in philosophy and how you want to implement a computer. Even then it still doesn't make sense to me, but to each their own, ya know?
Most likely I'll get a Shearwater Pursuit, as I plan on hitting trimix over the winter. I definitely like the Liquivision X1 more, but not enough for the price difference. If I wasn't going trimix in the immediate future, I'd most likely get a NiTek Trio.
I just don't get why anyone would buy a Cochran for that exact reason but I guess it's just a difference in philosophy and how you want to implement a computer. Even then it still doesn't make sense to me, but to each their own, ya know?
Most likely I'll get a Shearwater Pursuit, as I plan on hitting trimix over the winter. I definitely like the Liquivision X1 more, but not enough for the price difference. If I wasn't going trimix in the immediate future, I'd most likely get a NiTek Trio.
I agree, the lack of the ability to reject a scheduled gas switch is odd and such a feature would make the Cochran much more popular.
On the other hand when you are diving trimix and at depths where trimix is essential, the deco planning is only a small part of the overall plan. If a diver is computer dependent they are prone to jumping in with full back gas and deco bottles and then turning on pressure with a general idea of where they will be in terms of time and then ride the computer to the surface with a bottom timer and tables or custom backup and contingency plans on a slate.
I tend to go the other way. I will plan the dive from a time/depth/deco perspective with gas planning to ensure I am within a fairly conservative 1/3rd reserve and then ensure the back gas reserve and deco gas amounts are aedquate to handle the loss of either deco gas on a two deco gas dive, or in the event of a single gas dive that the back gas reserve is enough to do the longer back gas deco required.
Then during the dive, the bottom timer is the primary source of information, the custom deco plan and lost gas contingecies are on the slate and the computer is basically just back up and a short cut to the surface in the event of an early abort. In that regard the Cochran's limitation in not being able to cancel a planned gas switch is not much of a limitation in an offshore deep trimix dive. As indicated previously however, it is a potential PITA in a cave.
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The X1 is expensive, then needs $175 worth of software to boot. Plus it is basically a one man operation and relies on a rehcargeable non user replaceable battery, so if the one man decides to quit, dies, goes out of business for any reason you have a really expensive paperweight.
I like the Shearwater pursuit. The small company suffers from some of the same potential limitations, but the price point is much better and like Cochran you can start out nitrox only for well under $1000 and then upgrade later to add gases and flexibility as you move into more advanced diving.
I recently tried the Nitek X and was frankly not real impressed with the in water performance. At $1000 or maybe even $1200 I'd view it differently, but it just does not offer nearly enough for a $1600 computer.
For florida cave diving at nitrox depths, I recently opted for an Aladin Tec 2G as it does everything I require with low cost, good download capability, an inuititive interface and the ability to easily adjust the levels of conservatism.
On the other hand when you are diving trimix and at depths where trimix is essential, the deco planning is only a small part of the overall plan. If a diver is computer dependent they are prone to jumping in with full back gas and deco bottles and then turning on pressure with a general idea of where they will be in terms of time and then ride the computer to the surface with a bottom timer and tables or custom backup and contingency plans on a slate.
I tend to go the other way. I will plan the dive from a time/depth/deco perspective with gas planning to ensure I am within a fairly conservative 1/3rd reserve and then ensure the back gas reserve and deco gas amounts are aedquate to handle the loss of either deco gas on a two deco gas dive, or in the event of a single gas dive that the back gas reserve is enough to do the longer back gas deco required.
Then during the dive, the bottom timer is the primary source of information, the custom deco plan and lost gas contingecies are on the slate and the computer is basically just back up and a short cut to the surface in the event of an early abort. In that regard the Cochran's limitation in not being able to cancel a planned gas switch is not much of a limitation in an offshore deep trimix dive. As indicated previously however, it is a potential PITA in a cave.
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The X1 is expensive, then needs $175 worth of software to boot. Plus it is basically a one man operation and relies on a rehcargeable non user replaceable battery, so if the one man decides to quit, dies, goes out of business for any reason you have a really expensive paperweight.
I like the Shearwater pursuit. The small company suffers from some of the same potential limitations, but the price point is much better and like Cochran you can start out nitrox only for well under $1000 and then upgrade later to add gases and flexibility as you move into more advanced diving.
I recently tried the Nitek X and was frankly not real impressed with the in water performance. At $1000 or maybe even $1200 I'd view it differently, but it just does not offer nearly enough for a $1600 computer.
For florida cave diving at nitrox depths, I recently opted for an Aladin Tec 2G as it does everything I require with low cost, good download capability, an inuititive interface and the ability to easily adjust the levels of conservatism.
Right. The way I want to implement a computer is plan my dive using my v-planner desktop software to see how long I'm thinking of staying and how long I can stay while maintaining proper gas planning. Have tables in pocket with bottom timer on wrist, but use them as backup. I'm going to ride the computer as my primary means to decompression after planning out how long I can stay and familiarizing myself with different profiles.
A computer is a very expensive "back-up" device to tables, especially when it can't compute lost gas, which is one very good reason to need a contingency plan that actually does happen. So the Cochran is not really backing up much, IMHO, other than I stayed X minutes longer/shorter, or X feet deeper/shallower. Shame, it looks like an OK unit besides that.
I agree about the Nitek X. Don't see the point in spending that much money on what I can tell is a rebuilt Nitek HE with "product improvement" features that I'll never use. To me the VR3 doesn't do anything I want that the Shearwater Pursuit doesn't, and I'm not partial to their algorithm. The Liquivision really is great and without doubt the best computer money can buy from my standpoint, but that's a lot of money as you delineated. I'd love to have a Cis Lunar Mk5, but I think I'll settle at tens of thousands less for a Meg or rEvo, ya know?
A computer is a very expensive "back-up" device to tables, especially when it can't compute lost gas, which is one very good reason to need a contingency plan that actually does happen. So the Cochran is not really backing up much, IMHO, other than I stayed X minutes longer/shorter, or X feet deeper/shallower. Shame, it looks like an OK unit besides that.
I agree about the Nitek X. Don't see the point in spending that much money on what I can tell is a rebuilt Nitek HE with "product improvement" features that I'll never use. To me the VR3 doesn't do anything I want that the Shearwater Pursuit doesn't, and I'm not partial to their algorithm. The Liquivision really is great and without doubt the best computer money can buy from my standpoint, but that's a lot of money as you delineated. I'd love to have a Cis Lunar Mk5, but I think I'll settle at tens of thousands less for a Meg or rEvo, ya know?
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