Cheapest computer with liberal algorithm

[Kupu]

How to find out if the algorithm is liberal?

Find what algorithm(s) the computer is running by reading the literature or google.
If needed, there is plenty of info comparing the different algorithms online.

 

[tarponchik]

Find what algorithm(s) the computer is running by reading the literature or google.
If needed, there is plenty of info comparing the different algorithms online.

Has anyone actually tested comps side by side, taking them down into the deep and waiting which one starts beeping 1st, which one beeps last?

 

[VikingDives]

If memory serves me, I believe the puck runs RGBM. I used one for years. They were need conservative than cressi and suuntos.

The other option would be a deep 6. A little more expensive, but much more configurable as you can set gradient factors (in OC tec) and still get a ndl display.

 

[Kupu]

Has anyone actually tested comps side by side, taking them down into the deep and waiting which one starts beeping 1st, which one beeps last?

I know its not exactly what you mean, but that happens every time a group using different brands of computers goes for a dive.
Daily dive guides most days can look at a persons wrist and know what will beep first and last.

 

[tarponchik]

I know its not exactly what you mean, but that happens every time a group using different brands of computers goes for a dive.
Daily dive guides most days can look at a persons wrist and know what will beep first and last.

Most often folks run out of air sooner than that or the DM limits total time underwater. But OK, I'll keep an eye on that.

 

[Rob9876]

Another vote for mares puc pro. I used one for years. It's exactly what you've asked for with price and I always seemed to have plenty of time left on my NDL when other people were getting close (no idea what they were running).

+1 for Mares Puck Pro. My son and I have been diving them for years, and once we set it on the least conservative setting we've never felt hampered by it being too conservative. Also, everything I read before getting the Puck lead me to believe that the Puck was less conservative than Cressi Leonardo or Suunto.

I now also have a Shearwater Perdix 2, and yes it is slightly less conservative than the Puck Pro -- I usually still wear my Puck Pro also, and that is still what my son dives. However with the profiles we've been diving (44 dives so far using both, including 70 foot quarry dives, 100 foot Cozumel dives, 80-90 foot SE Florida dives, etc.), it really hasn't been an issue.

 

[lowwall]

Has anyone actually tested comps side by side, taking them down into the deep and waiting which one starts beeping 1st, which one beeps last?

There are many tests like this using pressure pots instead of dives. Scuba Diving magazine used to do them annually and even published the data.

Here's a fairly recent example. It only covers single square dives though. Repetitive and multi-level dives may lead to different results.

https://pureadmin.uhi.ac.uk/ws/portalfiles/portal/1904570/Sayer_Decompression_management_by_43_models.pdf

 

[scubadada]

Has anyone actually tested comps side by side, taking them down into the deep and waiting which one starts beeping 1st, which one beeps last?

Scuba Diving Magazine's ScubaLab used to run 4 standard dive profiles in the Catalina Hyperbaric Unit each year for their computer review. It was very good, objective data and was important because it reflected a clean 1st dive and repetitive dives. This is a brief description of the testing:

Objective Test Protocol​

To gauge the relative conservatism or liberalism of the computers’ algorithms, they were subjected together to a series of four dive simulations in the University of Southern California Catalina Hyperbaric Chamber. Meant to simulate a day of diving, the multistage profiles were: 100 feet/55 minutes; a one-hour surface interval; 70 feet/45 minutes; a two-hour surface interval; 80 feet/45 minutes; a one-hour surface interval; and 60 feet/40 minutes.

This is a link to the 2021 testing:

The Best Dive Computers of 2021

ScubaLab tested 11 new wrist and console dive computers in a hyperbaric chamber and with in-water testing.

www.scubadiving.com

Unfortunately, the link to the specific objective testing appears to be inactive. In the past, you could obtain these results for each year of computer testing.

I may be wrong, but the loss of this valuable information on dive computers seems coincident with Scuba Diving Magazine becoming the official publication of the PADI Club.

 

[PDodson]

Has anyone actually tested comps side by side, taking them down into the deep and waiting which one starts beeping 1st, which one beeps last?

The algorithms are based on different decompression models so we know the math built into them and which are more conservative. The main ones in computers being based on the Buhlmann and RGBM models. If you're interested in that more here's a great starting point, but there are a lot of good articles out there.

 

[tarponchik]

The algorithms are based on different decompression models so we know the math built into them and which are more conservative. The main ones in computers being based on the Buhlmann and RGBM models. If you're interested in that more here's a great starting point, but there are a lot of good articles out there.

Thanks! I've read something like this about a year ago when I was looking for a new comp for my wife. Such reports are too vague, like " Mares, similar to Cressi and Suunto, uses the RGBM algorithm, which is pretty conservative" or "The Pelagic Z+ used in Aqualung computers is a proprietary algorithm developed by Dr. John E. Lewis..." So I believe that only side-by-side field tests give the reliable answer. But ones that I find like this one compare comps for selling bullet-points, like "easy to view display", "long battery time" or "configurable algorithm" and so on. Which are important points but give you no idea on the conservatism or liberalism of algorithms used.