Geo 2 vs Cressi Newton

[Cald]

Hi mates. I'm gonna buy a new dive computer and after an hour research, I decided that the Geo 2.0 could be the best choice for me. After that, looking on the diveshop on line, I sow the Cressi Newton, new device that looks like have the same function of the Geo 2 but runs with a new algorithm. Someone has a direct experience with the Cressi? The difference of price is around 150 Au dollar but the Cressi Newton has a 5 year warranty(at least hier in Australia). Do you Know if the Geo 2.0 works with Mac? What about the new Cressi algorithm ?


Oceanic Geo 2.0 Technical Features

Powered by Oceanic's Exclusive Dual Algorithm&#8482; - Your choice between Pelagic DSAT (Spencer/Powell data basis) or Pelagic Z+ (Buhlmann ZHL-16C data basis)4 Operating Modes: WATCH (Alternate Time, Chrono, Daily Alarm, Countdown Timer), NORM (Air and Nitrox), GAUGE (with run timer) and FREE (tracks calculations to allow switching between NORM and Free)User-Friendly Interface with "Step Back" &#8211; allows forward and backward navigation through menus and settingsSwitch between up to 2 Nitrox mixes to 100% O2 with no restriction (Gas 1 may be up to 100%, and may be less or greater than Gas 2)Stop times <3 minutes - displays minutes & secondsDeep Stop with Countdown Timer &#8211; Maybe turned on or off.  2 minute countdown at half your max depth, for dives greater than 80 ft / 25mSingle button access to "Last Dive" display (max depth & bottom time)Data Retention - maintains calculations indefinitely when the battery is changedAudible Alarm with flashing LED light24 dive on-unit log bookHistory Mode includes total number of dives, max depth, total dive hours, and lowest tempOptional PC Interface with OceanLog Download and Settings UploadFirmware Auto-Update: download and install the latest firmware &#8211; these may be operational improvements or even new featuresPhysical Specs: TICKNESS 5/8", HOUSING 2.1/8", FRONT LENS 1.1/2", SCREEN 1.1/4"Now available with metric system.

Cressi Newton Technical Features

12/24 clock with minutes and secondsCalendarPrecision stopwatchSecond time settingAlarm clockMain computer function characteristicsDual-mixture CRESSI RGBM algorithm New algorithm created through a collaboration between Cressi and Bruce Wienke based on the Haldane model, integrated with RGBM factors for safe decompression calculations in repetitive multi-day dives and with mixturesSoftware handles two different hyperoxygenated mixtures, which can be selected during the diveCRESSI RGBM Algorithm. New algorithm created through a collaboration between Cressi and Bruce Wienke based on the Haldane model, integrated with RGBM factors for safe decompression calculations in repetitive multi-day divesTissues: 9 saturation half-times ranging from 2.5 to 480 minutes"Dive" Program: Full processing of dive data, including decompression if applicable, for every dive performed with Air or NitroxFull setting of FO2 parameters (oxygen percentage) and PO2 (oxygen partial pressure) with the option to set PO2 between 1.2 bar and 1.6 bar, and FO2 from 21% and 99%Option to take a Nitrox dive after one with air (even while desaturating)Option to set Deco (decompression calculation) or Gage (depth gauge and timer)Deep stop can be turned on or offDisplay with oversize digitsPlanning: decompression curve scrollingMetric or Imperial unitVisual and auditory alarmsGraphic CNS oxygen toxicity indicatorBacklit displayLog book (70 hr or 60 dives) complete with dive profileDive history savedOption for full reset if needed, helpful when renting the devicePC/Mac interface with simulator and dive profile (optional)

Dimensions:
Width: 48 mm
Height: 52.6 mm
Depth: 15.8 mm
Face diameter: 35 mm

 

[Yellowdog]

I can't speak to the Cressi except what I was told on my last dive trip but I do own 3 Geo 2.0s. I have one and both of my children do as well. I bought them on a recommendation from my daughter's dive instructor in Cozumel. He said he had used his Geo on over 1000 dives without a problem and it was his favorite dive watch /computer. He also said the diver's ability to change the battery yourself was a big plus. I have used the Geo 2.0 for over a year and find the computer reliable and intuitive. I have loaned one of my kids unused computers to two diver's whose computer failed on two separate occasions and both times they were really impressed after the dive and said they preferred it to the one they had.

The only thing I have heard about the Cressi is from another divemaster who said they are comparatively conservative and that when diving with a customer who has a Cressi he has to increase the conservative factor on his computer to more closely dive the parameters of his client.

 

[tbone1004]

go with the Geo, the "new" algorithm is still based on the similar algorithms they just made it more conservative. If you want to dive with that level of conservatism AUP's algorithms will have conservatism settings that will allow you to do that, certainly not worth spending an extra $150

 

[CptTightPants21]

Same as above. I love the Geo 2 as a first dive computer.

 

[Diving Dubai]

I had a cressi as my first computer, a Leonardo. Nothing wrong with it at all.

I dont buy into this conservatism argument. I never once had a problem with mine. But the I dive intros and pick the best gas mix

remember algorithms are a best guess and affect people differently

i will share with you an anecdote. Last year I was on a dive with my cressi. It was a wreck. My max depth was 30m. Another buddy pair went on the same dive with max depth of 24m. We all had the same gas and similar run time (perhaps theirs was slightly shorter). One of the pair, a DM with more than 500 dives got a minor DCS and spent the night in the chamber. Just because your computer says you're within safe limits doesn't alway mean you are, it has no idea about external factors.

frankly I'm happy not to dive to the max, and not have risk the chamber or worse. But like everything it's only my opinion

 

[pjhansman]

Three Geo 2's in our family too. One each for my wife and I plus I carry a spare. Easy to read and use. 3 years with no issues.

 

[tbone1004]

I had a cressi as my first computer, a Leonardo. Nothing wrong with it at all.

I dont buy into this conservatism argument. I never once had a problem with mine. But the I dive intros and pick the best gas mix

remember algorithms are a best guess and affect people differently

i will share with you an anecdote. Last year I was on a dive with my cressi. It was a wreck. My max depth was 30m. Another buddy pair went on the same dive with max depth of 24m. We all had the same gas and similar run time (perhaps theirs was slightly shorter). One of the pair, a DM with more than 500 dives got a minor DCS and spent the night in the chamber. Just because your computer says you're within safe limits doesn't alway mean you are, it has no idea about external factors.

frankly I'm happy not to dive to the max, and not have risk the chamber or worse. But like everything it's only my opinion

the conservatism shouldn't be determined by the computer due to their own algorithm putting weird stuff in to limit your NDL's, it should be a conscious decision by the diver to decide what level of conservatism they want to dive, hence why I think gradient factors are wonderful things because now the conservatism actually means something. Second gradient factor is the theoretical percentage of nitrogen saturation in your tissues when you surface. So x/70 means they are 70% saturated, and on and on. None of this "low" "medium" "high" crap where low means one thing to one computer and not to the other. This whole discussion about "newer safer algorithm" all means that instead of the computer tracking your theoretical tissue loading and having you come out with that same tissue loading from each dive, you now have arbitrary "things" that can cause them to knock your ndl's. For example, fast ascents, short SIT's, sawtooth profiles, etc, all impact your NDL's.

Now, explain to me why someone would spend $150 more for essentially the same computer to have what some might deem a safer algorithm, when it is essentially the same algorithm just with larger fudge factors?

 

[Diving Dubai]

Tbone:

I agree with your sentiments in principle, but you are coming from the perspective of a technical diver. I presume that your computer is used more as a bottom timer with your planning done before hand and strictly adhered to during a dive. I can't argue with you in detail as my theoretical knowledge of tissue sats is most likely not as deep as yours.

However these computers (With no disrespect to the OP) are generally used by newer divers. They don't have the level of understanding to choose anything greater than Low medium or high conservatism. And if they do choose one do they understand the implications of that choice? THe Geo has a choice of two algorithms - how many users in reality would be able to make an informed choice of which to choose from (I haven't read the Geo 2 manual so don't know if it is explained)

I have no issue with computers taking data like fast ascents, short SIT's, sawtooth profiles, etc, and using that data in the model to adjust the baseline figure - given that every dive is different.

Given the world we live in is one that people will sue because no-one told them the coffee in their cup was hot or that a vehicle was nearer than it appeared in their mirrors it's not surprising that manufacturers of entry level computers add more "headroom" to their calcs. As I understand it, all entry to medium level computers are generally more conservative than the top end models, purely because it is assumed that the entry level will be brought by less experienced divers.

THe fact that some people complain that their computer gives them 5 mins shorter dive then their buddy without considering that its possibly giving them 5 mins more safety head room always concerns me. If people want to dive to the max, then they should get additional training and learn more about tissue saturation etc. I wonder how many people remember what they were taught on their OW and Nitrox courses?

Regarding the justification on price difference (I found them to be $100 price difference) I can't. Its not my money. However I'm presuming that these computers will have more wrist time as a watch than a dive computer - so one should take that into consideration? I see that the Cressi has a mineral glass face which is more robust - that could be one reason for the price difference.

Having had neither computers I can't comment on their merits of either. I happen to know that my Leonardo was a trouble free dive comp and served me well for 2 years. I also know that when I dived it with my new computer at the end of 6 dives over 2 days the cressi would should show perhaps 20min less NDL time at depth on the last dive. It was never a problem as I mainly dive reefs where I can ascend from depth.

 

[scubadada]

I've been diving a Geo2 as backup to my VT3 for almost 4 years and about 425 dives. It has performed flawlessly. I just went to battery #3, changing is a cinch.

Regarding Diving Dubai's comments, the Geo2 is not just for beginner's, it has a fair amount of flexibility as a computer and works as a bottom timer. Many divers do not know much about decompression algorithms before purchasing a computer but should research this prior to a decision. It is not uncommon for divers to purchase a well known brand of computer, only to be disappointed later, when the algorithm proves to be overly conservative for their diving. You can adjust a liberal computer to be more conservative, nothing you can do with a conservative one. It appears DD has moved on to a more liberal computer after only 2 years, many quality instruments last much longer than that, my VT3 is 5 years old, over 500 dives, and going strong.

Best of luck in your computer purchase

 

[tbone1004]

regarding algorithms
Innovation » Computers
right at the top. Gives you examples of computers running similar algorithms. Tells you to choose DSAT for liberal recreational diving, and is based on PADI's RDP. Choose Z+ for conservative recreational diving, and liberal repetitive diving. There are obviously in depth explanations of each. If you you were taught a computer based class for OW or nitrox, and your instructor didn't explain conservatism levels and different algorithms for computers, you should demand your money back. If you were taught a tables based class and weren't taught the difference in the common tables you should probably ask the instructor wtf were you thinking. If you aren't smart enough to read the manual where it explains the difference in conservatism settings and how to choose the conservatism for that algorith, you're probably not smart enough to be using that computer so you should probably just call it quits while you're ahead and before you get bent....

I'll give you a hint, the settings are literally this easy. If you're risky, set it to liberal, if you're not, set it to conservative. Start at the top, if you feel good, set it to medium, if you still feel good set it to low, if you don't feel good, put it back. If you did things that put you at increased risk of DCS prior to the dive, put it one notch higher. Pretty much that simple.... Regarding gradient factors, they're actually incredibly simple to figure out, especially for NDL diving, and are actually significantly more conservative with most tech divers.

Petrel uses Buhlmann ZHL-16C, pretty standard in the technical community. This is the algorithm the Z+ for oceanic is based off of, and what Suunto, Uwatec, Mares, Tusa, etc use for their base, then they do stuff to it which pretty much ruins it, but that's ok. Now, 30/70 is a very common GF setting for technical divers, with 30/85 being common for some more aggressive divers. Shearwater has set the Low conservatism at 45/95, which means you come out with your tissues 95% loaded, this is similar to PADI/NOAA NDL times fwiw. Med is 40/85, and High is 35/75 *note, still less conservative than most divers use these things set at manually*.

Moral of story, unless you set the GF high at 100, you're diving the same level of conservatism as PADI's RDP, so you pretty much can't screw that one up. With GF's, start at 30/70, if you come out feeling good, bump it up to 80, if you feel good up to 85, then 90, etc. Or just leave it at 70 and accept that you will have shorter NDL's, nbd. Unfortunately the computer mfg's won't show their equivalent GF's, but they're probably pretty close to the GF's that Shearwater uses for their conservatism settings.