New Diver Looking At Suunto Zoop Or Geo 2.0

[scubadada]

I can't remember if I posted in this thread or not, but I know I have posted it before.

I was diving last Halloween weekend with a buddy that had a Cressi Giotto. Her computer consistently ended our dives when my Oceanic still had NDL time left. We only did 2 dives per day, for 2 days, so it was generally only a couple of minutes shorter, or so. But, when you are diving a wreck at 110' and only get 20-ish minutes anyway, 2 minutes is 10% of your bottom time!

I do understand that people doing consistently shallower dives are not likely to have an issue with the NDL on almost any computer.

The most dramatic, relevant NDL difference between say, DSAT, and Suunto, Mares, or Cressi, are at intermediate depths between 60 and 100 feet, the NDLs at deeper depths are quite short for all the algorithms.

 

[stuartv]

Yeah, I really meant depths generally in the 60' or less range where NDLs are generally so long that it just doesn't matter. Especially for people diving with a single AL80.

 

[stuartv]

Of course both of us the actual Cressi users on this forum claim we've never been limited by that alleged scary conservative "algorithm"... Remember: you heard this in the Internet so it must be true,

Anyway, this really pretty much nails it. Pay attention to some Internet anecdotes... or pay attention to controlled lab studies like have been posted from Scuba Labs (or whatever it's called). It's up to each person to decide for themselves what their priorities are for their computer and what sources of info to pay attention to.

 

[Steve_C]

The numbers from any computer are estimates from an algorithm with lots of safety factors built in. Assuming you understand your computer and its algorithm if you are on a Sunnto and need 2 minutes more of NDL than you have to take one more special picture or pick up a tooth that is right in front of you or more importantly get to the ascent line and you and your buddy have enough air, just do it with the understanding that you will be adding an extra 10 minutes of stop time at 15 ft if you do not want to tick off the computer. Nothing magical happens at 0 NDL. Or 1 NDL or -1 NDL.
I am not saying to ignore your computer. Just understand what it is and is not telling you.

 

[Willar]

Good point Steve_C. In some cases the Suunto will give you a long (5-7 minutes) "mandatory" safety stop. If you skip the indicated stop, the computer will penalize you on subsequent dives by reducing NDL time. If you violate it enough it will lock you out and only run Gauge Mode. It's always up to the diver whether to follow the computer.

 

[docmartin]

I dive with two computers. One is an old Aeris Atmos. The other is a Suunto Zoop. I usually stay within NDL on the Suunto and always clear both computers. My observations are that yes the Suunto is more conservative. No, it would not make that much difference for many dives especially newer divers.

Example Last Saturday we were diving two shallow flatish wrecks in 63 ft of water. So sort of square profiles in that depth varied from 63 to 55 during the dive. I was diving 31%. Dive one was 55 minutes TT, There was a 45 minute SI maybe a bit less. Dive 2 was 44 minutes TT. At the end of the bottom time on dive 2 my Suunto was at 4 min of NDL. My Aeris was at 23 minutes. Everybody else was back up on the boat except for one other diver, who was now my buddy, who had a tec computer of some flavor and was in doubles diving Nitrox 31% also. He said later his NDL was within a minute or two of mine.

Point is that I spent as much time at depth as anybody else on the boat and more than most.

I will add that knowing that the Suunto is more conservative and having information from a more liberal computer, I feel very comfortable riding the NDL on the Suunto.

That is in line with my experience - two typical, not very deep dives, SI less than an hour and DSAT gives you around 20 extra minutes of NDL. That is huge in my book.

 

[Nicole Chan]

Suunto are generally considered the most conservative computers on the market. This means they will reduce your Non Decompression Limit time quicker than other computers. You would see this most on repetitive dives over several days by having reduced NDL time compared to your buddy diving a more liberal computer. The time difference may be slight or several minutes. If you dive the Suunto and your buddy dives something less conservative, you may have to shorten the dive where your buddy still has time left (which I hear happens frequently with Suunto).

The Oceanic Geo 2.0 has more settings to allow you to adjust your conservative factor which will likely allow more bottom time on repetitive dives. When I dive with both a Suunto and Geo 2.0 I find the first day there is little difference but on repetitive dives, and especially repetitive deep dives, the Suunto will shorten NDL times faster than the Geo. And, as I move shallower, the Geo will add NDL time faster than the Suunto.

Some people feel the Suunto being more conservative is a good thing in that it reduces the chances of decompression sickness, some people think Suunto are too conservative and want a computer that will give them longer bottom times on repetitive dives. I dove the Suunto because, as a new diver, my local shop recommended it. When I added the Geo as a backup and comparison computer, I found the Geo shows more NDL time on repetitive dives. I always follow the more conservative computer but am thinking about retiring the Suunto and just using the Geo as I like the Geo better for several reasons.

The Vyper is a very good computer and so is the Geo. You may want to dive the same computer as your buddy so you match bottom times as much as possible. It's a personal choice with no one right answer.

Thanks so much for this Willar. As of the moment, i'm doing maximum of 2-3 days dive at a time so i guess the "conservative-ness" of the Suunto might not affect me too much. Being new to this, maybe i shouldn't worry too much about getting the perfect one that could last me well into the future but rather something i can use and later maybe convert into a back-up and really study how it works. I appreciate you taking the time to reply to my post.

 

[Willar]

Something I just thought about: When I compared the Suunto with the Geo 2.0 NDL times on my dives I had the Geo set to Z+ data basis with no added conservative factor. The Geo DSAT setting is more liberal and would give more NDL time than the Z+ setting (and, of course, even more than the Suunto).

 

[dmaziuk]

Thanks so much for this Willar. As of the moment, i'm doing maximum of 2-3 days dive at a time so i guess the "conservative-ness" of the Suunto might not affect me too much. Being new to this, maybe i shouldn't worry too much about getting the perfect one that could last me well into the future but rather something i can use and later maybe convert into a back-up and really study how it works. I appreciate you taking the time to reply to my post.

Some of us believe that "RGBM-based" computers reward you for long safety stops/very slow ascents in the top 7 or metres -- possibly even more than for longer surface intervals. And of course penalize you for doing the opposite. (Its a matter of belief because all entry-level computers are essentially black boxes and the exact details of their programming are not general knowledge.) The point being, if you take longer safety stops and slow down as you get closer to the surface, you may never run into Suunto's "conservativeness".

The other issue is that you're more likely to be affected if you dive with very large tanks, and two of them. With a single Al80 -- not so much.