"Deep Stops" or "Nitrogen Loading Bar Graph" on computer?

[Malpaso]

Two of the dive computers I'm researching have either a "Deep Stops" feature or a "Nitrogen Loading Bar Graph", but neither has both. I've tried reading up on the two subjects. While I understand the functionality of the bar graph, the whole subject of deep stops seems to have a lot of speculation/opinion surrounding it.

As I am a fairly new recreational diver, it appears to me that I would utilize the nitrogen loading bar graph, but maybe less so with deep stops, at least in the near future.

So, looking at these two computers, should having one or the other be a make or break?

 

[redacted]

I use the NLBG on my Oceanic Data plus as my primary tool for monitoring N2 loading. But it has a fairly high resolution graph with 15 NDL ticks, each worth about 6% loading on the leading compartment. I rarely look at NDL times unless I am deep and approaching the caution zone on the TLBG I can still do deep stops if I choose.

 

[miked]

IMO: if the choice is "one or the other, but not both", ( and I don't know if there is a computer with both) I'd go with the bar graph.

Reasoning:
There seems to be some level of disagreement on the value/execution of deep stops, even to the point of "what constitutes a deep stop"- half your max depth, half your max pressure, or.....; how long, etc.

That said, if the computer displays your max depth, you can determine the depth and time of a deep stop-whatever your definition of a deep stop may be. Of course, you could do that even without the bar graph.
I like the bar graph, as it is a nice visual reminder of N2 loading.

Good luck with your decision.

 

[Lorenzoid]

Bar graph is fairly standard, and I find it quite useful as a rough gauge. My computer has a deep-stop feature, but I have never used it. As miked said, there seems to me no consensus in the scientific community whether adding a so-called "deep stop" really has a significant benefit, and you can always initiate a stop on your own at any time. For example, on ascending from a deeper wreck dive I might stop for one minute at a depth that's around one-half the depth of the wreck.

 

[Doppler]

Two of the dive computers I'm researching have either a "Deep Stops" feature or a "Nitrogen Loading Bar Graph", but neither has both. I've tried reading up on the two subjects. While I understand the functionality of the bar graph, the whole subject of deep stops seems to have a lot of speculation/opinion surrounding it.

As I am a fairly new recreational diver, it appears to me that I would utilize the nitrogen loading bar graph, but maybe less so with deep stops, at least in the near future.

So, looking at these two computers, should having one or the other be a make or break?

Better answers if one knew the algorithm each computer was employing.

As an aside, I have never considered these features to be mutually exclusive.

 

[rhwestfall]

I'd rather have an idea of time (don't we plan time/depth/gas) than "two pixels in the yellow".... maybe its just me, but that just seems vague, and, unless we all have the same display, its worthless.... That time and my SPG also gives me an idea of remaining air time vs. NDL... again, validates time/depth/gas... guess its the engineer in me....


Anyone remember one of the early PDCs with the "man that filled up" over time?

 

[supergaijin]

From what I understand about Deep Stops to be effective, firstly you have to go deep. Much deeper than I ever dive. Richard Pyle was one of the first to talk about Deep Stops (aka Pyle Stops) when he noticed he felt less lethargic after deep deco dives while collecting fish from 300' and deeper. He was pausing to puncture the swim bladder of fish so they wouldn't explode from the ascent.

For a typical recreational diver, there is very little evidence to say that you'd benefit from Deep Stops.

 

[rhwestfall]

For a typical recreational diver, there is very little evidence to say that you'd benefit from Deep Stops.

except it does in fact make you pause, hence slowing your ascent, that it seems is still pushed by divers whom are at the lower end of certification levels.....

 

[Dr. Lecter]

The loading bar is really just another display for your NDL time, at least as I've seen it implemented. If the loading bar was more like the gradient factor display on a Shearwater, allowing you to see the changing theoretical GF in the leading tissue compartment as you change depth/time, I'd say you might find it more useful.

The deep stops in the alogrithm, however, may be an actual feature that you might actually use one day. Though you can plan and execute your own stops independent of the computer any time you like...so maybe neither feature is all that important.

 

[scubadada]

Simple question, complex answer. The value of deepstops for recreational diving is not established. See Decompresson and the Deep Stop Workshop Proceedings, Undersea and Hyperbaric Medical Society, 2008. Recreational limits generally allow free access to the surface without stops. The "safety stop" is a nonobligatoy stop designed to slow ascent and allow an additional safety factor. The deep stop may contribute to additonal tissue nitrogen loading during recreational dives.

For decompression diving, the deep stop is more firmly established. Deeper stops may allow one to maintain M-value gradient ratios below a predetermined value, allowing a certain amount of conservatism with regard to the risk of DCS. These M-value gradients are often able to be selected with more advanced dive computers, aimed at the more advanced diver.

Good diving, Craig