Spare dive computer with comparable algorithm?

Problem: The dive computer that I have been diving with had me surfacing before and longer safety stops than my group. (Mares Puck)

Solution: Get a dive computer that can match the algorithm of my dive partners at a affordable price for myself and my son.

Brands that will closely match my friends dive computer??? He is a dive guide and uses the Galileo Sol. I don't really want to spend that kind of money but want a cheapo version that will give me basics for air and nitrox and maybe apnea, and act as a back up computer for when I get the liquidvision Lynx.

I was looking at this one from leisurepro but cheaper would be better.


Cressi Leonardo Wrist Computer with PC Download | LeisurePro

All algorithms are different, even 'the same' algorithms differ from manufacturer to manufacturer. They do that so it's proprietary and don't infringe on copyright or intellectual property. The only way to have the same times as you're buddy is have the same computer and dive shoulder to shoulder. Does the cressi run a similar algorithm as the Galileo? And what's wrong with surfacing a little early and longer stops?

Look at the diving software program called 'V-Planner'....30 day free trial.....You won't need another computer, just a wrist slate........

Neither reply has addressed the question but thanks for the reply.

the Galileo Sol uses a ZHL-8 ADT algorithm.
it will be practically impossible to match this algorithm, you will even get different deco times if you use a Sol yourself.

From the scubapro homepage : SCUBAPRO - GALILEO SOL
Galileo is the first and only dive computer to have an integrated heart rate monitor, incorporating the heartbeat into the workload, and then tailoring the decompression calculations to YOUR dive. We are the only dive computer manufacturer in the world that accounts for the effect of increased workload on human physiology during a dive,

gearbow:

Problem: The dive computer that I have been diving with had me surfacing before and longer safety stops than my group.

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First: Safety stops are optional, so you aren't constrained to surface separate to your group. When provided by a computer (any computer) these are generally arbitrary and typically 3min between 3-6m.

Some computers will provide "mandatory" safety stops if your diving has been haphazard enough to warrant a more critical precautionary stop in shallow water. These can vary in duration, but are always quite short. If you ignore them (which you can), you will get penalized on subsequent repetitive dives. The answer: don't dive in a haphazard manner, especially in regards to ascent rate.

Other than that, you'd be talking about Deco Stops. That shouldn't be on the table, given your stated training level and knowledge (i.e. what you're asking on this thread).

gearbow:

Solution: Get a dive computer that can match the algorithm of my dive partners at a affordable price for myself and my son.

Click to expand...

Relative algorithms:

Mares Puck: Wienke-Modified RGBM
Scubapro Galileo Sol: Adaptive BuhlmannZH-L8 ADT
Liquivision Lynx: Buhlmann ZH-L16C-GF (optional RGBM upgrade)
Cressi Leonardo: Wienke-Modified RGBM (9 tissue)

*with Buhlmann derived algorithms, the numerical (after "ZHL-") describes the number of theoretical tissue compartments used.

You will find this to be an interesting article: A sense of algorithm - Divernet

gearbow:

Brands that will closely match my friends dive computer??? (Galileo Sol)

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Here's your choice (reference/source):

As of 2009, the newest dive computers on the market use:


Liquivision X1: V-Planner Live: VPM-B Varying Permeability Model and GAP for X1: Bühlmann GF (Buhlman with Gradient Factors)
Mares: Mares-Wienke Reduced Gradient Bubble Model
Pelagic Pressure Systems: modified Haldanean/DSAT Database or Bühlmann ZHL-16C(called Z+)
Seiko: Bühlmann ZHL-12 + Randy Bohrer
Suunto: Suunto-Wienke Reduced Gradient Bubble Model
Uwatec (Scubapro): Bühlmann ZH-L8 /ADT (Adaptive), MB (Micro Bubble), PMG (Predictive Multigas), Bühlmann ZHL-16DD (Trimix)
Heinrichs Weikamp OSTC and DR5: Bühlmann ZHL-16 and Bühlmann ZHL-16 plus Erick Baker's Gradient Factors deep stop algorithm both for open circuit and fixed set point closed circuit rebreather.


As of 2012:


Cochran EMC-20H: 20-tissue Haldanean model.
Cochran VVAL-18: nine-tissue Haldanean model with exponential ongasing and linear offgasing.
Delta P: 16-tissue Haldanean model with VGM (variable gradient model, i.e., the tolerated supersaturation levels change during the dive as a function of the profile, but no details are provided as to how this is done).
Mares: 10-tissue Haldanean model with RGBM; what the RGBM part of the model does is not described in detail anywhere and is not available to the public.
Suunto: nine-tissue Haldanean model with RGBM; what the RGBM part of the model does is not described in detail anywhere and is not available to the public.
Uwatec: eight-tissue Haldanean model.

---------- Post added October 16th, 2013 at 05:27 PM ----------

j2s:

Look at the diving software program called 'V-Planner'....30 day free trial.....You won't need another computer, just a wrist slate........

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The latest iteration of 'V-Planner'; 'Multi-deco' (available same site) is even better - algorithm options.

gearbow:

Problem: The dive computer that I have been diving with had me surfacing before and longer safety stops than my group. (Mares Puck)

Solution: Get a dive computer that can match the algorithm of my dive partners at a affordable price for myself and my son.

Click to expand...

I'm not quite sure what your problem is. Are you saying that your computer gives you shorter NDL's and longer safety stop times than your buddy? That would mean it's just more conservative, which most people don't necessarily see as a bad thing.

If your computer is the more conservative one then the obvious solution would be for both you and your buddy to leave the bottom when *your* computer says it's time. This is the normal procedure when divers have different computers... always follow the most conservative one.

Your buddy's computer also has "Micro Bubble Levels" which can be set to 5 or 6 different levels, L0 being the least conservative and L5 being the most. Maybe getting your buddy to set his conservative setting to L1 or L2 would bring his calculations more in line with what your computer does.

The way I see it, you don't need a new computer, you just need to get on the same page with your buddy.

R..

Lets forget computers for a moment. They are irrelevant.

Your buddy stays longer at depth and surfaces quicker? And (s)he does not die?

OK...

If we assume that you do not go deeper than your buddy, then you can do exactly the same decompression as (s)he does.

An exception: If you are in very poor shape, overweighted, and have an elevated breathing rate, then you may need more time to offgas, but if you and your buddy are about similar, then you'll need about similar offgassing times.

It is generally a very bad idea to follow a buddys computer (especially if you have done dissimilar amounts of dives during the last 24-48hrs or the week) - but some common sense may be usefull. You have probably noticed that no computer takes into account the breathing rate or your pulse (and these ARE relevant). All profiles are thus on the safe side. Some tech computers allow for more customization and living on the edge, but this is not the case for rec computers.

Perhaps you should do some calculations using V-planner or other VPM-based software, and see what kind of decompression/bottom time is generally needed. Then you should read the Deco for divers book and understand the limitations of the models.

This comparison from Scuba Diving magazine is a couple years old but likely still relevant:

http://www.scubadiving.com/files/old/images/pdf/200806_chambertest.pdf

You can see that the Mares is consistently the most conservative computer they tested (other than on dive #4). It also conveniently shows how the Galileo compares to it and why your buddy has more bottom time. Unfortunately there's no Cressi tested here, but from the above, it looks like Cressi uses the same base algorithm as the Mares, so they should likely be very similar.

I personally am a fan of Oceanic PCs: They are the most liberal (DSAT), the current ones have a choice of a more conservative algorithm (Z+ no idea how it compares to other algorithms though), and can be made more conservative if one wishes.

Diver0001:

... it's just more conservative, which most people don't necessarily see as a bad thing.

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Oddly enough, I see a common trend on Scubaboard that indicates the opposite. People do criticize certain algorithms/computers for being conservative.. and make great positive noise about the more liberal ones.

It's like...somehow... they believe if the computer says "you're ok", then you must be "ok"... and that your personal safety and physiological insulation from DCS changes in reflection to whatever numbers are displayed on a digital screen...