Are Suunto Zoops super conservative?

[scubadada]

@dmaziuk @rsingler @tursiops et al.

The original source of this graphic is the Oceanic website, an attempt to explain dual algorithm with DSAT and PZ+
Innovation » Computers There is no detailed explanation for the graphic but I believe it is a dive profile, it is certainly not 1st dive NDLs at those depths. Note that the x-axis is dive time in minutes. The y-axis is NDL in minutes. I can't figure out exactly what the profile is, but it seems like an ascent from 80 to 60 ft from 12 to 26 minutes, an ascent from 60 to 40 ft from 26 to 42 minutes, etc. It doesn't really matter, you get more NDL with a liberal computer than with a conservative computer when comparing the same dive profile/depth exposure. This is not rocket science.

The table that tursiops posted makes this quite clear. There are significant differences in 1st dive NDLs when you compare liberal, middle of the road, and conservative decompression algorithms. The table makes this extremely clear.

The logical question is what happens during repetitive dives. The answer is about the same, you get more NDL from a liberal deco algorithm than from a conservative algorithm. There's not much data for repetitive dives. ScubaLabs does a 4 dive simulation in the Catalina hyperbaric chamber each year it tests computers for Scuba Diving Magazine. You can ridicule the magazine as much as you want, the data is fine. Here is a link to the 2014 data http://ads.bonniercorp.com/scuba/PDF/ScubaLab-Computer-Test-September-2014-data.pdf Data from more recent years can be downloaded as an Excel spreadsheet from the Scuba Diving Magazine website. Here is a link that will allow you to download the 2017 data that includes both Shearwater 45/95 and 40/85, in addition to several other computers/deco algorithms 11 New Dive Computers Tested By ScubaLab In 2017

These concepts are not that difficult, not sure why there seems to be so much ongoing confusion and debate on SB. Liberal deco algorithms give you more NDL on 1st dive and on repetitive dives than a conservative computer. The effect of repetitive dives may be made more complex by secret adjustments made in these, mainly proprietary, algorithms.

Glad we are now all on the same page

 

[Umuntu]

deleted

 

[tridacna]

deleted

Jawellnofine. Wink.

 

[scubadada]

Some of the data from @tursiops post as a line graph:

 

[KenGordon]

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.

Your Perdix has a planning mode which will tell you the NDLs. If the tables offered above are true then in Rec mode the longest NDL for an air 30m dive would be 15 minutes. So using the 28 minutes given by a Zoop set to 32% would be quite far past the Perdix.

This thing with setting a Suunto to Nitrox when diving air, and not knowing about the Perdix planning mode I find a bit worrying. Can I suggest you find a local instructor (certainly nobody to do with the person in the diving business you mentioned earlier, and preferably one qualified to teach deco courses) and give them some money to explain all this to you? As a stop gap you could try reading Mark Powell’s book ‘Deco for Divers’ (available as an ebook).

I was in a hole in the ground near Chepstow today. It was 11C at the surface and 7C on the bottom. The sea is about 13C supposedly, but wind etc... There is an old joke, ‘There is no such thing as bad weather, just the wrong clothes.’ it goes for water temperature too.

 

[Snoweman]

Your Perdix has a planning mode which will tell you the NDLs. If the tables offered above are true then in Rec mode the longest NDL for an air 30m dive would be 15 minutes. So using the 28 minutes given by a Zoop set to 32% would be quite far past the Perdix.

This thing with setting a Suunto to Nitrox when diving air, and not knowing about the Perdix planning mode I find a bit worrying. Can I suggest you find a local instructor (certainly nobody to do with the person in the diving business you mentioned earlier, and preferably one qualified to teach deco courses) and give them some money to explain all this to you? As a stop gap you could try reading Mark Powell’s book ‘Deco for Divers’ (available as an ebook).

I was in a hole in the ground near Chepstow today. It was 11C at the surface and 7C on the bottom. The sea is about 13C supposedly, but wind etc... There is an old joke, ‘There is no such thing as bad weather, just the wrong clothes.’ it goes for water temperature too.

Let me know when you get to warm water. I will do my best to dive with you then.

 

[salth2owannabe]

I have two Suunto Cobra models and have dove with them for a number of years. When I purchased these, much of my decision was based on their display clarity and lay out and I knew little about Algorithms. Last year, on a trip to Belize, the sensor on the Suunto went belly up and only functioned as a pressure gauge. As a result, I decided to purchase an Oceanic Geo 2.0 to take along with my Suunto AI after it was fixed. The Oceanic was set on the DSAT algorithm and no conservative factors were added/adjusted to the Suunto. My intention was to compare the two for a few dives and essentially use the Suunto as a gauge. I thought I'd share my Anecdotal experiences-
I realize there isn't a generic dive profile but for warm water diving we generally did the "standard" 80ish on the first dive, 60ish on the second and so on, most dives lasting about 55-60 min. Only mentioned as we didn't do anything unusual.
First day of diving we did a morning and an afternoon dive. The second day of diving we did two morning dives. Three dives/day follow that with the trip to the Blue hole on the third day.
What initially surprised me was that on the first three dives the two computers gave somewhat similar numbers, with the Suunto being slightly more conservative. The forth dive however, and for the rest of the week, the Suunto began to show it's conservatism. On two tank dive mornings with about an hour + surface interval, the Suunto would consistently start into Deco minutes when the Oceanic showed 44-45 minutes of no deco dive time left. On one dive I had racked up 10 minutes of deco time on the Suunto while the Oceanic still showed 22 minutes of no deco time left. One thing that also surprised me about the Suunto was that once I went into a deco dive it appeared to clear little or no time when I ascended and continued the dive, until I got to it's required 18' (I had the deep stop option turned off).
I never violated the Suunto during the 10 days, which made for some extra time bobbing around at 15'. Not so much by choice but I couldn't get it to switch from air to gauge mode. I knew you couldn't switch out of gauge for 48 hrs after a dive but from what I could find you could switch to gauge or nitrox from air. At about day 8 I got it to switch to nitrox and played around with it comparing the two at a few different mixes on the Suunto, but that's another story. Just thought I'd share my personal experiences, yours may very.

 

[boulderjohn]

On two tank dive mornings with about an hour + surface interval, the Suunto would consistently start into Deco minutes when the Oceanic showed 44-45 minutes of no deco dive time left. On one dive I had racked up 10 minutes of deco time on the Suunto while the Oceanic still showed 22 minutes of no deco time left.

I went to Truk Lagoon for a week of liveaboard diving quite a few years ago, when I was still using a Suunto Cobra. My dive buddy was using an Oceanic with the DSAT algorithm. At midweek he started calling me "Captain Deco." The difference was simply enormous by then.

I never violated the Suunto during the 10 days, which made for some extra time bobbing around at 15'. Not so much by choice but I couldn't get it to switch from air to gauge mode. I knew you couldn't switch out of gauge for 48 hrs after a dive but from what I could find you could switch to gauge or nitrox from air. At about day 8 I got it to switch to nitrox ...

I don't remember how I got it to switch to nitrox mode from air the first time--I thought it had to be 24 hours. Somehow I did it. I learned that there was never a reason to put it in air mode. Just leave it in Nitrox mode and set the level to 21%. Most intelligently designed computers don't have an air mode--you just set the O2 percentage.

Getting it to gauge mode is pretty easy, as I discovered by accident. I can't remember how it happened, but I ended up doing a week of ocean diving using the Cobra as backup and pressure gauge while I used a new computer--exactly your situation. As I was doing my second dive the first day, it suddenly occurred to me that I had not used the Cobra since I had been diving in the Denver area, at high altitude. Since you have to set the altitude by hand, it was still set on high altitude. I checked, and sure enough, I was well into deco on a simple NDL dive. Realizing that I only needed the Cobra as a pressure gauge, I just followed the other computer. The Cobra went into error mode, which is exactly the same thing as gauge mode. I used it that way the rest of the week. No problem.

 

[loady]

Two weeks ago I dove both the mares puck pro and suunto zoop novo, at the same time on 17 dives.
I was on nitrox, from 28-32% O2.
That's what the boat provided.
The mares has three algorithms from more liberal to more conservative. I found that on all three, I had much less no decompression time then on the Suunto. With both computers set to the same mix and both on my arm each dive, the mares was reading up to 25 min. Less time no deco time. That's strange because I've read that Suunto has a very strict conservative algorithm. Is this normal? Should I send the mares in for an evaluation? Or could the Suunto been on the liberal setting?

 

[boulderjohn]

The mares has three algorithms from more liberal to more conservative.

Do you really mean it has three algorithms? Or does it have three levels of conservancy? I thought they both used the RGBM algorithm.