What to Choose?

[Diving Dubai]

Hi @Diving Dubai

Your Eon Steel (and the Eon Core and DX) run Fused RGBM. They run Technical RGBM down to 40 m (on air, nitrox, <20% helium) and switch over to full RGBM from 40-55 m. The P-2 setting is quite liberal, similar to 45/95 and DSAT.

The new D5 runs Fused RGBM 2, said to give shorter ascents from deep air dives and on repetitive dives using air/nitrox

Thanks for the correction on the Switch over depth

Eon Core and Steel get Fused RGBM2 at next firmware update, I was led to believe that basic RGBM will also get updated to a RGBM2 at some point

None of this changes my support to your original post where someone questions Buhlmann on Repetitive dives where I say there's nothing to choose between Buhlmann and Fused RGBM - and my experience suggests basic RGBM is not much behind depending on the conservative factors applied.

 

[D_Fresh]

While this is all very good technical discussion regarding algorithms (and I dig it), I fail to see how this helps the OP make a decision on selecting a computer when they're not yet certified, or making deep technical deco dives.......

 

[dmaziuk]

How is it that you’ve had the opportunity to view the source code for a proprietary RGBM implementation?

By "you" I meant "one": a generic "you" that includes myself. I haven't seen Shearwater implementation of ZHL, nor a Cressi RGBM. I know more about the former but I also have a fair idea how many "implementation details" may be lurking in there. So in reality either is a black box to me, just different shades of black.

 

[lexvil]

While this is all very good technical discussion regarding algorithms (and I dig it), I fail to see how this helps the OP make a decision on selecting a computer when they're not yet certified, or making deep technical deco dives.......

It doesn’t help the OP, it’s just the typical thrashing about in the weeds which often happens once the rails are jumped.

 

[dmaziuk]

100% expected when you ask on SB what to choose between a D5 and a Perdix.

My recommendation is to buy two of whatever it is so when they pop up on fleebay a year later, I can get one for myself and one for my perma-buddy at the same time.

 

[stuartv]

I get paid for writing open source code, I can promise you that until you see the actual code with comments and explanations, the difference between "proprietary" RGBM and "non-proprietary" implementation of ZHL with GFs is six vs half a dozen.

By "you" I meant "one": a generic "you" that includes myself. I haven't seen Shearwater implementation of ZHL, nor a Cressi RGBM. I know more about the former but I also have a fair idea how many "implementation details" may be lurking in there. So in reality either is a black box to me, just different shades of black.

I take this to mean that you have not looked at the actual code for Cressi (or Suunto) RGBM. In which case, I fail to see how you can promise someone that the difference between either of those implementations, as compared to ANYTHING else, is six vs half a dozen.

Because six and half a dozen are the same.

As far as I can tell, those implementations are "the same" to you in the sense that any 2 things that you know nothing about are "the same". A hi def CRT and an LCD flat panel both show you the same image. When you know nothing about what's inside one (or both) of them, to you they are "the same".

To be clear, I'm not saying there is anything incorrect about what you said. I'm just getting clarification on the context of your statement. You can promise someone that a hi def CRT and an LCD flat panel are six vs half a dozen. Got it.

 

[dmaziuk]

I'd like to point out that anyone can debate relative merits of CRT vs LCD just fine, especially on the Internet. (Plus, I know more about their insides than I know about Cressi RGBM.) And as I usually get to pick those things off desks and cart them to the people doing the decommissioning paperwork, my back is painfully aware of which of the two is better.

 

[KenGordon]

I take this to mean that you have not looked at the actual code for Cressi (or Suunto) RGBM. In which case, I fail to see how you can promise someone that the difference between either of those implementations, as compared to ANYTHING else, is six vs half a dozen.

Because six and half a dozen are the same.

As far as I can tell, those implementations are "the same" to you in the sense that any 2 things that you know nothing about are "the same". A hi def CRT and an LCD flat panel both show you the same image. When you know nothing about what's inside one (or both) of them, to you they are "the same".

To be clear, I'm not saying there is anything incorrect about what you said. I'm just getting clarification on the context of your statement. You can promise someone that a hi def CRT and an LCD flat panel are six vs half a dozen. Got it.

His point was that an apparently proprietary RGBM and an apparently open GF implementation are equivalently opaque.

He says this because of all the question open to the implementer he has encountered while doing his implementation. I found the same. I have several flags which swap behaviour about which I can’t see is prescribed in a particular way.

This is especially true of the choices about being a planner (how GF was proposed) vs being a live dive computer.

 

[dmaziuk]

Also if I can plan my dive on DM5 and execute it on a Vyper, while you can plan yours in Subsurface and execute on a Teric, the only practical difference is you get more planner software choices with the latter. Including a DIY planner. It's not nothing but... I wonder how many end-users even care.

I'm pretty sure if I go a no-stop dive with my RGBM computer and overstay my NDL a little, I'll have a "non-optional safety" stop at 3 metres. Just as one would expect. Do you know your Shearwater would generate in the same situation on your chosen "recreational" GFs?

 

[scubadada]

I would love to see some kind og

Also if I can plan my dive on DM5 and execute it on a Vyper, while you can plan yours in Subsurface and execute on a Teric, the only practical difference is you get more planner software choices with the latter. Including a DIY planner. It's not nothing but... I wonder how many end-users even care.

I'm pretty sure if I go a no-stop dive with my RGBM computer and overstay my NDL a little, I'll have a "non-optional safety" stop at 3 metres. Just as one would expect. Do you know your Shearwater would generate in the same situation on your chosen "recreational" GFs?

Hi @dmaziuk

I thought you were still diving your Cressi computer, is that right? I have a very good idea how my DSAT or Buhlmann ZH-L16C with GF computers would behave in deco, do you have the same experience?