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Discussion Starter #1
Hi
What was your reasoning for doing so and at what point in your dive career did you adopt it? What was the persuader for doing so?
Thank in advance.
Rgds
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Suunto

I changed mine after about 50 dives. That was a few years and 350 dives ago. I found the conservatism a bit too conservative on some shallow dives we did.
I use a Vytec. Friday I used the multigas nitrox mode, Saturday in gauge mode on a trimix dive.
 

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Shallow dives

Thank you.
What depth do you term shallow dives?
Rgds
Wibble
The dives in question were 20-25m
I tend to regard 20m dives as shallow-no redundancy required
20-30m requires backup such as a pony
30m+ requires twinset, possibly stages, possibly trimix

Most sea diving for me is 30-35m. Friday was 52m at Chepstow :redface: and Saturday 50m :cool: off Weymouth
 

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if i RGBM50 is the least conservative option, then that's what i use. the vytec is a shockingly conservative computer. having switched to it from my aladdin pro-ultra, i feel like i'm diving with my hands tied.

i don't even feel that the suunto comptuers (vs. aladdin) are safer because it wants you to get shallow fast and doesn't seem to give you much deco credit for a nice slow ascent. i could go on.... :)
 

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I use the 50% setting - but then again I do a completely different profile from what the Suunto wants (i.e. I don't go rocketing up to 6m and do all the deco there[1]). On the whole this way it works out quite well, with the full 100% it was penalising (sp?) too much for the deep stops that I was adding in.

[1] - the Suunto does have a sliding ceiling but I'm simplifying things.
 

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Discussion Starter #7
Thank you all.

The duck, so do you do 50%rgbm and deep stops on the Vytec?

I would still like to know others experiences of 50%RGBM
Rgds
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I use the 50% setting - but then again I do a completely different profile from what the Suunto wants (i.e. I don't go rocketing up to 6m and do all the deco there[1]). On the whole this way it works out quite well, with the full 100% it was penalising (sp?) too much for the deep stops that I was adding in.
me too. I have the DS function turned off & put in my own Pyle-esque deeper stops
 

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i use 50% with the deep stop turned off.

do mala stops instead depending on how i feel.
 

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50 v 100

Hi
What was your reasoning for doing so and at what point in your dive career did you adopt it? What was the persuader for doing so?
Thank in advance.
Rgds
Wibble
Why not tell us more about your dive experiences and what diving you are looking to do. It may assist with any further answers.
 

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The so-called RGBM is not. Its a penalty stop for fast ascents. Either turn the thing off to use the core Bulhmann or leave it on to get the "benefit" (if you think it has one - I'm not sure but my Suunto runs 100%)

The Suunto is not "conservative" this is a misunderstanding of its algorithm. What it does do (and is annoying) is fail to give much if any credit for the mid part of the ascent. So if you do things properly it penalises you (and so appears conservative)

In the final analysis its a depth-timer like any other and has a built in bit of software that guesses at what decompression you should do. For serious decompression diving its neither use nor ornament (it tells you this in the manual if you read it :D)

To be honest the "50% RGBM" is just bullshit.

Chris
 
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Discussion Starter #12
Ian 1904. In answer.
I am a recreational, holiday diver, of only some 3 years, PADI, AOW, NITROX and Deep, I have only dived in warm waters, some wrecks, reefs, caverns etc. looking around and taking photo's.
I have had a few issues on some trips where most of my buddies and guides have had Suunto DCs, I have racked up some ascent times where others have not, this I thought was due to my being on the end of a long series of dives whereas others I was diving with had just arrived and started their holidays. So I discounted the differences and being in the shallows was happy to bimple about and do the time.
However, on a recent trip to Gozo I buddied with a chap who was on a Uwatec, from the off he stated "yours will be more conservative and we can go by yours". All cool, so at the point where I had racked the time agreed, I checked his Uwatec, this had barely started to register Deco, we came up did the stops in mid water and I was very aware that he was waiting for me to finish. In a nice way, not bored or getting antsy. A very good buddy and I have expressed my thanks to him for his tolerance of what I considered to be just a difference in Algorithms.
So at the end I decided to do some digging (he doesn't get bent so why should I, if I adjust my profiles) into adjusting my times and post here for opinions.

Hope this helps
Wibble
 

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..... adjusting my times ...
Setting it to 50% RGBM will not change the deco time - it affects the penalty for fast ascents.

Chris
 

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Hi
What was your reasoning for doing so and at what point in your dive career did you adopt it? What was the persuader for doing so?
Thank in advance.
Rgds
Wibble
I changed mine before the first dive (i had one of the first non DS vytecs after having a Nexus for gas switching)

why ? It was not clear in the manual what difference it would make and I was using it in conjunction with 30/85 GF. I can dive a sensible profile I don't need some silly computer to fiddle with Buehlman - I can do that.

Since then a friend has dived it and a gecko together on 100 ish dives and it appears the only really difference between the two computers (suunto on 50%) is that the gecko gets into deco on the second dive a bit more quickly

Tony
 

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The so-called RGBM is not. Its a penalty stop for fast ascents. Either turn the thing off to use the core Bulhmann or leave it on to get the "benefit" (if you think it has one - I'm not sure but my Suunto runs 100%)
interestting, can you turn it off on a vytec (not DS btw)?

The Suunto is not "conservative" this is a misunderstanding of its algorithm. What it does do (and is annoying) is fail to give much if any credit for the mid part of the ascent. So if you do things properly it penalises you (and so appears conservative)
interesting, that's the first time i've heard this. is there any way to get around it?

cheers

andrew
 

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However, on a recent trip to Gozo I buddied with a chap who was on a Uwatec, from the off he stated "yours will be more conservative and we can go by yours". All cool, so at the point where I had racked the time agreed, I checked his Uwatec, this had barely started to register Deco, we came up did the stops in mid water and I was very aware that he was waiting for me to finish.
hi wibble, that's certainly my experience too. what model uwatec did he use? was it an oldie or one of the newer rounded ones? i would change my vytec if i found a suitable alternative.
 

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interestting, can you turn it off on a vytec (not DS btw)?
As far as I know you can turn off (or set to 50%) the "RGBM" on all the Suunto range. You can on the Vyper and the Vytec is more feature-rich so I would be very surprised if you cannot (turn it off).

interesting, that's the first time i've heard this. is there any way to get around it?
...
Read some of Mark Chase's stuff on the Suunto algorithm.

To get round it set the thing to gauge mode and use a proper deco planner.


I run a Vyper2 and mostly just (lazily) follow the instructions. The downside is you are getting a bit too much deco. This is not really a downside IMO. Adding some extra shallow stop time is worth doing and helps with repetitive profiles and if you want to drive up a hill or fly home.

The Suunto dive manager simulator is a handy tool and can be used to compare the profile against something like V Planner.

My understanding of the new "make it up as you go along" Pyle stops gimmick added to Suunto is that they give you some credit for the deeper stop. Sadly this has to be made at an arbitrary depth (as per the Pyle guesswork) and is unlikely to fit the careful calculations you have made using your software package. Again its a wild guess fudge that might or might not work (whatever "work" means).

I think, in all honesty, for recreational profiles the Suunto will give you a reasonable guess at deco provided you're following more or less a square profile and not true multi level stuff. I personally am happy enough to use one for UK diving. For anything over about 10 mins deco I would use V Planner (and the Suunto as a depth timer)

Chris
 

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thanks chris, very helpful. i have used deco software in the past, but to be honest, i rarely plan dives these days and my diving is pretty tame.

andrew
 

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Discussion Starter #19
Sipadan
It was an old one a Uwatec air Z Nitrox (I think)

Chrisch
"50% RGBM does not change the deco it affects the penalty for fast ascents". So does it knock back the danger of microbubble ! mark that sometime appears impressing on you that you need an extended surface interval?
Also can you point me at Mark Chases Suunto algorithim postings?

All...

Thnak you very much fo all info and opinions posted.
Rgds
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