Petrel v. Vyper :)

[victorzamora]

What's normal to low?
How many dives do most rec. divers who are buying computers and other gear have?

I only do a handful of rec dives per year, at most. Last year, I think I did 5 recreational dives. You asked how many dives I did in a given year, and I responded with the number of dives suitable to this discussion.

As I said, I don't think most SB members including you fit the average rec. diver profile. The average rec. diver does not teach scuba nor does he/she tech. dive.

I don't care what you teach or what tech diving you do, the math is the same. The algorithm is the same no matter what experience you have diving.

When I do planned deco dives my SAC is much higher than my normal average which is .54. I'm also 6'5" 250, but what does that have to do with the price of tea in China?

Not the price of tea in China....NDLs. My having a relatively higher SAC rate means that I DO have room to speak about gas limiting my dives. If I'm hitting NDLs with my SAC rate, I'm sure others are, too.

 

[John_B]

I disagree, I don't think it's an invalid test at all.

There are a lot of recreational divers who do 4+ Nitrox dives per day for a week on a liveaboard, etc. and those are exactly the people who would be "penalized" by the Suunto model for repetitive dives. If anything, I'd like to see what the differences would be between the Petrel and the Vyper after a week, not just two dives.

 

[victorzamora]

I disagree, I don't think it's an invalid test at all.

There are a lot of recreational divers who do 4+ Nitrox dives per day for a week on a liveaboard, etc. and those are exactly the people who would be "penalized" by the Suunto model for repetitive dives. If anything, I'd like to see what the differences would be between the Petrel and the Vyper after a week, not just two dives.

You're right. The Suunto algorithm will penalize those divers doing 4+dives per day. His test was one single dive. My problem wasn't the Nitrox, it was that it was one shallow(ish) dive, not the repetitive diving I have a problem with. The Nitrox just exacerbated the issue and further hid the problem. Nitrox diving 4+ times per day will stay showing issues on Suunto. Just like 4+air dives.

 

[scubadada]

Cool, are you diving air, AL80s?
Can you post some profiles or plan the first two sample dives and post the bottom time allowed?

Nitrox 32%, yes AL80s. First dive below of 85 minutes, avg depth 52 feet, had no NDL remaining but did not go into deco. Second dive 80 minutes, avg depth 44 feet, 2 minutes of NDL remaining. The first dive listed was actually the 2nd of the day. First dive was 56 min on the Castor at an avg depth of 76 feet with 3 min of deco. Did just these 3 dives on August 12

 

[LowVizWiz]

Nitrox 32%, yes AL80s.

Thanks for posting!

Man, it sux to be getting old... My eyes are failing me I can't see the thumbnails very well!
I blew them up to 300% and it was just a blurr can you attach them actual size?

---------- Post added August 22nd, 2014 at 12:08 PM ----------

Nitrox diving 4+ times per day will stay showing issues on Suunto. Just like 4+air dives.

Please anyone post some profiles showing this...

I have done a week of diving in Coz 25 dives, Belize 27 dives, Roatan 26 dives, Panama 22 dives. All on air. I've also done it with nitrox in Bonaire, The Keys, Coz, etc. A lot of those dives were diving with people from this board who do not dive Suuntos. All of those dives on AL80s (Except the Keys I brought my own tanks) with Suunto computers. I didn't have issues once with bottom times. Gas on the other hand was an issue, but I'm not trying to measure me.

I've seen my profiles and I've seen the claims that the dives are limited by the conservative NDLs. I'd love to see some profiles.

 

[BugHunterNY]

I don't have comparison data, but my first DC (when I was certified as a young teen in the 90s) was a Mosquito. For years as a warm water vacation diver - I LOVED that computer. As my diving progressed to NorthEast Wreck diving, the suunto became a backup initially, but I kept locking it out... Pretty much every time I was on the boat my suunto locked up and my petrel barely hit deco. It's now pretty much a log book sitting in the bottom of my crate. Hasn't been wet in ages.

I've heard good things about the Dx though, supposedly a new algorithm combination to slide between rec / tech needs. Anyone have any experience with the Dx? Be interested for some tech feedback and or anyone used it on CC?


Sent from my iPad using Tapatalk

 

[gekodivebali]

My biggest problem with Suunto computers is the way they deal with deco. Once deco starts, minutes ratchet up very fast. The obligation to stick very close to the ceiling for deco to clear is a huge problem. This makes no sense from a physiological point of view on many dives.
I've even seen the deco obligation not clearing on a dive with pure O2 used for deco at 5m. This is purely idiotic.
IMHO, Suunto computers should not be used for deco. I tolerate them on my dives where no deco is involved with models that you can set at 50% rgbm (not the Zoop).
Lastly, I found that on dives with light deco on bottom gas, the GF setting that most closely resembles the Suunto'50% rgbm is GF40/85.
Hope this helps.

 

[scubadada]

The Sept/Oct issue of Scuba Diving contains dive computer reviews. The repetitive dive NDL data is available as a download supplement ScubaLab: How We Test Dive Computers | Scuba Diving

 

[Slamfire]

My biggest problem with Suunto computers is the way they deal with deco. Once deco starts, minutes ratchet up very fast. The obligation to stick very close to the ceiling for deco to clear is a huge problem. This makes no sense from a physiological point of view on many dives.
I've even seen the deco obligation not clearing on a dive with pure O2 used for deco at 5m. This is purely idiotic.
IMHO, Suunto computers should not be used for deco...

I have a Mares Puck that uses the Mares flavored rgbm (same as Suunto?). It does behave the way you describe. If it wants you to do 7 mins of deco at 10ft, you better be at 10ft. If instead of 10ft you do it at 15ft, the computer still says 7mins but you will have to do something like 13 real minutes in order to clear out all 7 the computer is demanding.

Again, it gives you predictability problems. I see no practical reason to twist the algorithm in this way other than protecting the manufacturer against legal liabilities. Thus the diver ends up following instructions that are not for his best interest but rather that of the manufacturer. Yes, the resulting real profile is more conservative in terms of DCS prevention, but it blinds/deceives you with false information that is crucial to the estimating of required gas supplies.

 

[LowVizWiz]

The Sept/Oct issue of Scuba Diving contains dive computer reviews. The repetitive dive NDL data is available as a download supplement ScubaLab: How We Test Dive Computers | Scuba Diving

Thanks for the link!
I would have love to see the repetitive dives extended out to 60 minutes, but quite interesting still.
Good stuff there.