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‘SUUNTO SAYS’
Another Perspective by CochranUndersea Technology
www.divecochran.com
Suunto: "Unlike the classical Haldane models, the RGBM
[ReducedGradient Bubble Model] can address a number of circumstances outside the range of just dissolved gas models by:[1] -Monitoring continuous multi day diving.[2] -Tracking closely spaced repetitive diving.[3] -Accounting for diving deeper than previous dive.[4] -Regulating rapid ascents with high degrees of Doppler bubble formation."This statement is blatantly untrue! Virtually all modern algorithms comprehend and adjust for
[1]"…continuous multi day diving" and [2]"…closely spaced repetitive diving" regardless of the type of algorithm.Regarding
[3]"…Accounting for diving deeper than previous dive",this is not related to the type of algorithm used. For many years, the algorithm developed by Cochran adjusted for "diving deeper than previous dive" since that was the prevailing belief by leading researchers. Recently, researchers have reversed that belief and now state that the order of deep or shallow dives is irrelevant. Consistent with that new research, the new Cochran computers allow the user to select whether they want no adjustment at all or a small adjustment.Suunto is not up to date with current diving philosophy.Regarding
[4]"…Regulating rapid ascents with high degrees of Doppler bubble formation",this statement just doesn’t make any sense! There is no such thing as "Doppler bubble formation". One might assume they mean microbubble formation as a result of rapid ascents. For many years, the algorithm developed by Cochran has adjusted for this effect. Suunto is just now beginning to?The obvious omission in the new "
modern"Suunto algorithm is that it has no comprehension of the diving environment. In our opinion, it is unacceptable for a dive computer algorithm to be totally unaware of the water temperature, changes in diving altitude, water salinity,and for air-integrated models, the all important Workload Factor. Many years ago, Cochran was the first to produce a dive computer that comprehends these factors. Suunto still does not.
Suunto: "The SUUNTO RGBM [Reduced Gradient Bubble Model] implementation is developed in co-operation with SUUNTO and …"
Some years ago, Cochran reviewed that RGBM. After reading the papers, and after discussions at our Factory in Texas, we concluded that we did not want to switch. We believed it did not comprehend some important factors that were inherent in the Cochran model, and could find no reason to change.
Suunto: "Powerful Memories, which store the most important dive data and register the time and date"
Actually, they can only store a very small total of 6,480 samples while Cochran’s Gemini family stores over two million samples!!! That includes over 500 dive summaries and over 550 dive hours at one second sampling!!! That is more than Flight Data Recorders on commercial aircraft!!!
Suunto: "With Suunto computers more afterwards traceable dives have been made than with any other brand."
We question how they think they know this since we were never asked how many dives we have. Since 1989 (with NASA) Cochran has had the most storage and the fastest sampling and the highest resolution of ANY other computer. It is far more likely that Cochran has substantially more dives than anyone.
Suunto: "The American 'organisation' (organization) DAN (Divers Alert Network) is using the Suunto dive profile memory function to establish a data base of computer-assisted dives"
The fact is, DAN is also using Cochran computers for the same reason. Both Cochran and Suunto have donated computers to DAN for this purpose. According to leading researchers, if the profile sampling rate is not less than five seconds,the important Ascent Rate parameter cannot be accurately reproduced. This is a major topic of research at this time. Only Cochran computers go down to one second sampling. Suunto cannot be used for this research because their fastest sampling rate is ten seconds.
Suunto: "Distinct ascent rate meter to show your ascent speed."
Cochran’s Ascent Rate indicator can be configured by the user to show Fixed or Variable Ascent Rates, and can even be configured as Proportional to depth.In addition, the user can also change the Responsiveness of the indicator as well as the audible alarm. They can’t do any of this!
Suunto: "Suunto’s decompression method – continuous decompression– is one of the most natural decompression methods available."
Their decompression ceiling display changes by the foot while others change every ten feet. The diver must be exactly at this depth or some units will not allow decompression credit. Cochran displays decompression ceiling every ten feet, but if you are above or below that ceiling, it continuously computes (once per second) the appropriate decompression credit based on your current depth that second. Furthermore, Cochran has expanded the Ceiling limits to be the same as the Depth limit of 325 feet.!!! The new Cochran Gemini and Commander computers do not ‘Lock–up’ or ‘Gauge-out’ when parameters are exceeded.
Suunto: "For your safety, you can choose your own – personal safety level – and adjust your Suunto computer for diving at high altitudes."
With Suunto, you get three choices of altitude that you have to set: 0 to1000ft, 1000ft to 5000ft, and 5000ft to 10000ft. This very course adjustment for altitude can have significant effects on Nitrogen loading. Barometric Pressure changes can cause changes in effective altitude of up to 2000ft! In our opinion, any Dive Computer that does not automatically adjust for small changes in altitude (caused by barometric changes or actual altitude) is putting the diver at risk.
Suunto: "Suunto is the only manufacturer to offer three alternatives[for setting Conservatism, or Personal Safety]".
Cochran was the first to let the user enter their own degree of safety, wecall that ‘Conservatism’. Cochran allows the user to enter a Conservatism number from 0 to 50% instead of just three.
Suunto doesn’t talk much about their primitive methodology for sensing and adjusting for Altitude. Like many other obsolete Dive Computer technologies, their altitude must be set manually and does not automatically comprehend changes in altitude. This can have very serious effects on Nitrogen Residuals.
With Cochran, Altitude is automatic and seamless, you just forget about it. Even when off, it automatically senses changes in altitude and adjusts itself automatically!!!
One of the more deleterious omissions by Suunto is the complete disregard of
changes in barometric pressure and altitude. When the body is subjected to increasing altitude (decreasing barometric pressure), Nitrogen residual MUST be considered increased. If a dive at the new altitude is started before the Nitrogen is eliminated, it MUST be considered a repetitive dive, not a new, clean dive!Even ten years ago, Cochran dive computers, measured and comprehended changes in barometric pressure and altitude.
Suunto: "The electroluminescent backlight provides excellent illumination in darkness and in low light conditions."
Cochran’s active fiber-optic backlight provides an efficient red glow that is very easy to see, yet does not lead to ‘night blindness’ like some other types. For those who have difficulty seeing the color Red, the backlight is even available in other colors.
Suunto: "The battery power indicator tells you the power status at all times. Your nearest dealer changes the battery for you in a matter of minutes."
With Cochran’s Gemini family, you get over 1,000 dive-hours of battery life, or two years. Then, just use any type of ‘AA’ battery and replace them yourself. Furthermore, the Cochran Gemini Family has dual-redundant power systems. If one should flood a battery compartment or a battery go bad, the other compartment takes over without any interruptions.
Suunto Manual: "NOTE! When the battery is changed, all nitrogen and oxygen uptake is lost. Therefore, before changing the battery, the no-flying time shown by the computer should have reached zero. Otherwise, wait for 48 hours or preferably even 100 hours before you dive again."
With Cochran’s new Commander and Gemini family, critical Nitrogen and Oxygen data are not lost during battery changes. If the batteries are changed when the Battery Warning comes on, you have over one minute after removing the batteries to replace them. With the Gemini, replace the batteries one set at a time at your leisure.
Suunto Manual: "NOTE! It is imperative that the [battery] change is made in a proper manner to avoid any leakage of water into the battery compartment or computer."
Cochran’s new Commander and Gemini family have battery compartment(s) that are sealed from any other components and can be flooded without any damage. All it takes is a coin (supplied with Product) and a few seconds to change batteries (spares supplied with Product). With Suunto, there is a two-page section in the manual that explains how to change the battery and requires a Philips screwdriver, a soft cloth for cleaning, and Needlenose pliers or small screwdriver for turning the securing ring.
Suunto uses one relatively uncommon, expensive, lithium battery. The Cochran Gemini uses four common, low cost, ‘AA’ batteries of any type (Alkaline recommended). The Cochran Commander uses two common, low cost ‘N’ batteries of any type (Alkaline recommended). Cochran gives you a spare set of batteries with the Product.
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