Confused: Suunto D4 Safety Stops

[Bubbletrubble]

I'm not that well versed in the different decompression model theories. But, is micro build up related/a precursor to DCS in the RGBM model? I would assume then that skipping the mandatory safety stop has a material increase in the chance of a DCS? I guess what i'm asking is how does a mandatory safety stop differ from a mandatory decompression stop in reducing the chance of a hit. Or is it the same, the difference being one is to reduce risks arising from fast ascent and the other from too much nitrogen loading?

You're overthinking this. "Mandatory Safety Stop" is a phrase created by Suunto. It doesn't have any grounding in deco theory, nor does it speak to a nuanced difference from a "mandatory decompression stop." It means exactly what Suunto defines it to be -- nothing more, nothing less. It can be assumed that, according to Suunto's proprietary RGBM model, fulfilling the "mandatory safety stop" will result in a cleaner decompression given the instance of an ascent rate violation.

 

[Kresna]

Just read this and I just want to clarify few things. I used D4 and these are my understanding from user manual. Please correct me if I am wrong.

1. Recommended Safety Stop, if violated, has no penalty, nor lock the computer. Safety Stop is always (strongly) recommended by all diving school/agency and never become mandatory.

2. Mandatory Safety Stop is additional terminology by Suunto for exceeding ascent rate. Violation will be penalized by shorten "No Dec Time" and (unknown) prolong surface interfal.

3. Decompression Stop is needed when you exceed "No Dec Time", hence your dive become Decompression Dive. Instead of perform a deco stop at fixed depth, Suunto allow you to do "continuous decompression" at variable depth depend on your dive profile. The computer will be locked for 48 hours if deco stop is not completely performed.

4. Answering the question on How do you know that the stop is Mandatory Safety Stop or Deco Stop according to Suunto dive computer's display? In my understanding, if there is a "Ascent Time" sign appear, then its a Deco Stop.

Again, apologize if i am wrong, please do correct me.

Thank you very much.

Kresna

 

[Kresna]

Now, few questions

Now my questions:
1. I have never been in deco situation. If you do, am I right in saying that D4 will ask you to a certain shallower depth (ceiling) for certain minimum time. Then as you are in decompression process while you ascent, computer ceiling (and floor) change to shallower depth? As for the decompression time, it depends on how close you are from the ceiling.

My confusion is, in the manual example illustration, the diver was at 25m when deco and the computer pointed straight to 3m ceiling (not any deeper depth). Is that the situation when you got deco. Before I used D4 (this is my first divecomp btw) I was told that you have to go to 3m (no more or less) and perform deco stop according to what your computer tell you. That's quite similar with these example.

2. About deep stop. Even if i put the deep stop mode on, my D4 still activate the Safety Stop. Its on the manual p. 49. One of my friend's D4 doesn't activate safety stop when in deep stop mode. I thought it just an error or he just missed it. But I read some similar case in this thread. Is it the old D4?

Kresna

 

[DiveNav]

See the D4 in deco with divePAL and/or int the Suunto D4 online class

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[Hatul]

Now my questions:
1. I have never been in deco situation. If you do, am I right in saying that D4 will ask you to a certain shallower depth (ceiling) for certain minimum time. Then as you are in decompression process while you ascent, computer ceiling (and floor) change to shallower depth? As for the decompression time, it depends on how close you are from the ceiling.
View attachment 111315
My confusion is, in the manual example illustration, the diver was at 25m when deco and the computer pointed straight to 3m ceiling (not any deeper depth). Is that the situation when you got deco. Before I used D4 (this is my first divecomp btw) I was told that you have to go to 3m (no more or less) and perform deco stop according to what your computer tell you. That's quite similar with these example.

2. About deep stop. Even if i put the deep stop mode on, my D4 still activate the Safety Stop. Its on the manual p. 49. One of my friend's D4 doesn't activate safety stop when in deep stop mode. I thought it just an error or he just missed it. But I read some similar case in this thread. Is it the old D4?

Kresna

In my Vyper, probably the same as D4, when you enter deco, it shows an upward arrow indicating you should ascend above the floor. It also shows you the ceiling (3m) and the total ascent time. You're fine to be below the ceiling as long as you're above the floor, in fact Suunto recommends doing the 3m (10ft) deco at 15 ft to avoid going above the ceiling. The deeper you are from the ceiling the longer the deco stop will take. Also often as you ascend slowly above the floor the deco will clear if it's short, as in accidental deco.

Adam