Suunto RGBM vs Buhlmann ZHL-C

[Scubanoobi]

I have a question that I was hoping somebody could help answer. I currently have a Suunto which everyone knows runs a pretty conservative algorithm. I know the algorithm well and I know what I can do to minimize the RGBM "penalties". I'm fairly happy with my computer.

Having said that, the new OLED computers are appealing and most seem to be running Buhlmann with GF's, which I don't know a lot about. I'm strictly a recreational diver staying within ndl's. Looking at the ndl times for the petrel (40/85 - medium conservatism) and deep black (30/85 - low conservatism) it shows less time at say 100 feet on a first dive on air (10 minutes vs 17 on my Suunto).

My question is simple, for recreational diving within ndl's, will the petrel or xdeep be less or more conservative than my Suunto for repetitive or multi-day diving? Dive #1 seems to show the Suunto as less conservative.

Thanks

 

[victorzamora]

Suunto's profile does, in fact, penalize aggressively for repetitive dives. Dive 1 will be more liberal on the Suunto (as long as you don't saw-tooth, ascend quickly, descend below a certain arbitrary depth, miss a safety stop, etc).....but repetitive dives will not be as liberal.

The other thing to mention is it's not just a matter of conservatism you should be looking at. Just following the computer that gives you the longest bottom times might not be the most responsible approach. You should be seeking a computer running a full, published, deco algorithm that won't arbitrarily punish you for a bunch of different things. Even without the repetitive dive penalties of Suunto's "model" I'd MUCH prefer to dive Buhlmann and be able to understand and follow a full algorithm that simply tracks what I'm doing.

 

[Scubanoobi]

Thanks Victor, I'm not looking for a computer that will give me the longest bottom time as I also have an oceanic (DSAT) but always follow the Suunto. I just wanted to make sure that I wasn't going get something more conservative than my Suunto.

Or should I just shut up and buy a petrel...

 

[rongoodman]

It's hard to say much about what Sunnto's RGBM does, since it's proprietary. If you want to run a bubble model, you could buy a Shearwater and add VPM. A full implementation of RGBM is available for the Xeo too.

 

[victorzamora]

Or should I just shut up and buy a petrel...

So you HAVE read these threads before.....

 

[ajduplessis]

Shut up and buy a Petrel!

 

[Lorenzoid]

To echo what others said, my only objection to Suunto's proprietary implementation of RGBM is that it's sort of opaque--most of us are unable to predict very accurately how it will behave on an unfamiliar profile, especially repetitive profiles. I have never felt my Suunto computer unduly limited my diving. My diving style is very laid back--an hour is a long dive for me, an hour surface interval is the norm for me, and four dives a day is about all I want to do. I do have a good feel for how my Suunto will behave during my typical dive days--say, for example, a week on Bonaire. I, too, am looking at a Petrel as my next computer because I like the big, bright screen. But I doubt the transition to a Buhlmann algorithm would have much impact on my diving.

 

[victorzamora]

It's hard to say much about what Sunnto's RGBM does, since it's proprietary. If you want to run a bubble model, you could buy a Shearwater and add VPM. A full implementation of RGBM is available for the Xeo too.

It's funny because the one benefit a"bubble model" (VPM specifically) really has is in how it treats helium-rich mixes and associated deco on super long bottom times. What's extra funny is that some of the divers doing those dives are cautiously tending away from VPM due to being overly liberal and bending a bunch of people.

---------- Post added December 3rd, 2014 at 11:17 AM ----------

I also have an oceanic (DSAT) but always follow the Suunto. I just wanted to make sure that I wasn't going get something

If you have a "dual algorithm" oceanic computer you can switch to Z+ algorithm.... which is a modified Buhlmann. I MUCH prefer it to the DSAT algorithm despite it being more conservative.

 

[guyharrisonphoto]

IF you are satisfied with your Suuntos and know how to manage the algorithm to your liking, Suunto just came out with their full-color EON steel, so you could get the display you are looking for with an algorithm that you are already familiar with.

 

[scubadada]

If you have a "dual algorithm" oceanic computer you can switch to Z+ algorithm.... which is a modified Buhlmann. I MUCH prefer it to the DSAT algorithm despite it being more conservative.

Hi Victor, the DSAT algorithm is great for recreational dives, it is not optimal for deco dives. Many readers do not have the background to be able to interpret your statements

Good diving, Craig