Are Suunto Zoops super conservative?

[boulderjohn]

While I am not a fan of Suunto in general, the simple fact is that the computer does not make you spend 5 minutes at a stop instead the normal 3--your inability to stay at the stop depth made you spend 5 minutes at the stop instead of the normal 3.

I do a lot of decompression diving. This past weekend, on one of my dives, my ascent included about 100 minutes in decompression stops. If the computer tells me to stop at 60 feet, it wants me to stop at 60 feet, not somewhere in a range from 55-65 feet. If I go to 59 feet, it will warn me that I am missing the stop and penalize me if I stay too long above 60 feet. If I stop at 61 feet, it will add a little time to my deco schedule. It will not add much for only 1 foot below, but for each foot below the stop depth, it adds a little more time. When you are hovering for 80 minutes, believe me, you don't want to be adding a lot of time unnecessarily, so you stay pretty darn close to the indicated depth.

I guess I am not feeling a lot of sympathy for people who have that much time added to their safety stop because they could not stay within a 10 foot range for most of 3 minutes.

 

[tursiops]

You want to stay longer than me at depth, be my guest. What does the colourful infografic has to do with it?

I don't think I'll ever get it.

I'm unclear why that infographic is so confusing/irritating to you! It is simply a graphical way to show that the NDL from several different computers is not the same, even for the same BT and depth. Tt is NOT a multi-level diver profile, which you seem to hint at. The exact same into could have been shown in a table. Would that be more helpful?

 

[scubadada]

..I don't think I'll ever get it.

You and I finally agree

 

[Snoweman]

Ok, get yourself on a plane and I’ll take you for a dive.

On a less flippant note, as maybe you don’t really understand, the Suunto NDL for 30m on 32% is 28 minutes (17 for air). Multideco gives 6 minutes of stops for 28 minutes at 30for GF100/100. Your Perdix would certainly give more. So the advice you were given could have you missing a lot of stops.

Using a richer mix to decrease conservatism is a bad plan. On the face of it it seems ok, pretend you got less gas, seems easy. However the equations are not linear, so over time the error is hard to guess. Also it will have you OFF gas faster, so a multilevel dive might be REALLY wrong as the computer starts giving credit when it should still be adding penalty. It doesn’t matter how big the limit is if you fool the computer that you are walking away from it.

First, where do I fly to? If it's cold water, forget it though.

Second, what are the NDL's for Perdix, on air for the low, medium and conservative settings at 30m? I try to Google this information, but it's not an easy search.

 

[tursiops]

First, where do I fly to? If it's cold water, forget it though.

Second, what are the NDL's for Perdix, on air for the low, medium and conservative settings at 30m? I try to Google this information, but it's not an easy search.

The last three columns are for the Shearwater Recreational Mode. For 30m/100 ft, for low, medium, and high conservatism, the NDLs are 15, 12, and 9 minutes.

 

[scubadada]

...what are the NDL's for Perdix, on air for the low, medium and conservative settings at 30m?...

Redundant post, @tursiops beat me to the draw

 

[dmaziuk]

I'm unclear why that infographic is so confusing/irritating to you! It is simply a graphical way to show that the NDL from several different computers is not the same, even for the same BT and depth. Tt is NOT a multi-level diver profile, which you seem to hint at. The exact same into could have been shown in a table. Would that be more helpful?

I doubt it.

The way I see it, the computer is not like a table or dive planner: it computes its best guesstimate based on the data now. As I'm sure you know your NDL now is determined mostly by your controlling tissue compartment now. If that's e.g. the 4-minute compartment, wait 4 minutes and the computed NDL will change.

So when the picture shows me the NDL changing in a straight line from 26 to 43 minutes, it smells of repurposed bovine waste: I am not convinced it works that way for RGBMs that apply a variable fudge formulae to calculations, I am not convinced it works that way when controlling compartment changes and so on. Maybe it does, but I have doubts. I want to see the actual continuous NDL line plotted on top of the actual dive profile.

 

[dmaziuk]

deleted

 

[Snoweman]

View attachment 437726
The last three columns are for the Shearwater Recreational Mode. For 30m/100 ft, for low, medium, and high conservatism, the NDLs are 15, 12, and 9 minutes.

Great graphic. Where did you find it?

 

[tursiops]

I doubt it.

The way I see it, the computer is not like a table or dive planner: it computes its best guesstimate based on the data now. As I'm sure you know your NDL now is determined mostly by your controlling tissue compartment now. If that's e.g. the 4-minute compartment, wait 4 minutes and the computed NDL will change.

So when the picture shows me the NDL changing in a straight line from 26 to 43 minutes, it smells of repurposed bovine waste: I am not convinced it works that way for RGBMs that apply a variable fudge formulae to calculations, I am not convinced it works that way when controlling compartment change and so on. Maybe it does, but I have doubts. I want to see the actual continuous NDL line plotted on top of the actual dive profile.

Thanks for this explanation. It clarifies that you do misunderstand the diagram. The only data points are the little colored dots. The lines connecting them are, well, just lines connecting them. The lines are there to (try to) help you see that a particular computer/algorithm is consistently above or below some other computer/algorithm. So in no way does that diagram try and show that "the NDL [is] changing in a straight line from 26 to 43 minutes" but rather that the NDLs for two different Bottom Times (26 and 43 minutes) are different. You are trying to read the graphic (horizontally) as the NDL for a given computer/algorithm as you change BT. Rather, it should be read (vertically) as the differing NDLs for different computers/algorithms at a few selected BTs.