advise on a dive computer....

[JimJam2]

I would stay away from Suunto, Cressi and Mares computers.

Why is that? Makes me happy to see this as I just spent big $$ to upgrade my Suunto Lux S to Oceanic's Pro Plus 3.

 

[Ricardo V.]

David,
Congratulations on your investment. It's a great computer, I've had them for some time now, maybe close to 10 years, they are well made, reliable, easy to use and built solid.
Read the manual, familiarize yourself with its features and with some basic TLC, it will last you for years.
Ricardo

 

[David Putnam]

Did you get the transmitter? Did you get the heart rate monitor? Just wondering.

Yes have the transmitter, No heart monitor.

 

[Diver0001]

I would stay away from Suunto, Cressi and Mares computers.

@David Putnam

It wasn't explained in the post I quoted above why that user would avoid these brands. My assumption, which I hope he will confirm, is because these three brands of computers use a decompression model called RGBM.

There are two main decompression models used by almost all computers. RGBM is one and the other major decompression model in use today is Buhlmann (ZHL-16-C). There are some computers that use other models as well but they are bound to be either a variation of RGBM or a variation of ZHL-16-C Buhlmann. RGBM is an example of what divers call a "bubble model" and Buhlmann is an example of what divers call a "Haldane model".

So that is terminology that you will hear on the internet. In the big picture, they both try to skin the same cat but in very different ways that I will try to explain if you have additional questions.

Why is this important?

The RGBM model suggests to the diver to made a deeper "ascent line", essentially going to the surface slower. It includes so-called "deep stops" during a long ascent or an ascent whereby the diver has exceeded the NDL's. Buhlmann does not include "deep stops" (getting shallow faster) but can be artificially "tweaked" to simulate deep stops using settings that most modern (technical) computers have, called "gradient factors". More terminology for you.

For a number of years, starting by the early 1990's and continuing until about 2011, deep stops were considered to be a good thing because some technical divers were reporting feeling better after big dives when they did them. Chief among those was Dr. Richard Pyle who was forced by the nature of the work he was doing to do "deep stops" and he reported feeling less bonked after those dives. It should be noted that Dr. Pyle is a marine biologist, not a decompression specialist but he's a well known name in diving circles and people started copying his technique and reporting similar benefits. Deep stops were initially called "Pyle stops" for this reason. You will hear both terms on internet forums.

However, definitive research done fairly recently by NEDU (Navy Experimental Diving Unit) raises serious questions about the "deep stop" strategy. To make a long story short, their conclusion was that deep stops they way they are currently implemented by "bubble models" can lead to more risk to the diver, rather than less risk, which is what deep stops purport to do.

The research was done in the context of significant incursions past the NDL's. In the context of recreational diving, it is unclear whether or not RGBM puts the diver at similar risk. My personal interpretation of what I know about this is that it does not. The NEDU results were ground breaking for technical divers, but if you are not making technical dives then it would appear in the absence of further research that the "issues" with bubble models only start to show up when they start making very extended deep stops.

That said, in principle @BurhanMuntasser is right in the sense that NEDU shows us the RGBM is in need of calibration. For that reason, I believe he was advising you to avoid computers that use them. Personally, I would buy one for my daughter. I don't know if this will help you make a decision but I do hope it will help fill in some of the puzzel for you.

R..

 

[dmaziuk]

Why is that?

They don't work well in Lybia.