Am I the only one that dives with 2 computers?

[RJP]

However, the bottom is the bottom.

On some Cayman walls "the bottom" is a L-O-N-G way down.



---------- Post added September 8th, 2015 at 09:48 PM ----------

Or, what am I missing?

The point.

As mentioned, my original comment was about whether a Suunto was too conservative to be an effective back-up computer to something else, based on my own real world experience of doing ~1,000 dives with a Suunto over a period of ten years. During that time it has never - never ever - caused me to thumb a recreational dive earlier than I or my buddy wanted to end the dive.

So the point is that, sure the article is interesting, and people can certainly give some consideration to those numbers. Clearly, someone who wants to use a Lynx as their primary computer would find the Cressi Leonardo to be a very poor choice as a back up. The practical reality is that pretty much everything else in there is about the same. Let's not discount the fact that the article tested ONE each of a handful of computers over four artificial, exquisitely controlled dive simulations. Not ten of each over a large number of real dives done by real divers. Hell, consider the fact that the two Mares computers running the exact same algorithm give different NDLs at all points in time.

The ultimate "real world" implication is that the computer on your wrist has no way of communicating how much remaining NDL it is "giving you" to the nitrogen bubbles in your body, so different computers don't really "give you more NDL time" -- forget that at your own peril.

Using a dive computer is the equivalent of measuring with a laser, marking with chalk, and cutting with an axe.

 

[KEdiver]

I am not a tech diver but yes I have a Zoop and Scubapro

 

[AdivingBel]

Land based 2 to 3 dive standard rec dive profiles (one deep - 2 shallow with 1 hr SIs), one computer. Very few scenarios I couldn't continue diving albeit a bit more conservatively. After off gassing overnight I would rent/borrow a fresh computer the next day and keep on diving. Absolute worst case (can't think of what that would be offhand) I could skip a day hanging out at the pool or seeing the sites. Not the end of the world. Liveaboard 4 or more dives a day without shore access, 2 computers every dive. Not blowing that kind of trip on a bum computer.

 

[Steve_C]

I have a Zoop and an Aeris Atmos. On a recent pair of dives to 80 ft or so. I and my buddy dive HP100s at 30%. On dive 2 we were NDL limited. We started up when the ZOOP hit 0. My Aeris was showing 7 minutes more. As soon as we started up the Aeris begin to give me more time. The ZOOP did so much more slowly. Going up say 10-15 ft and I was seeing a difference that got up to 15 minutes. Up further they both gave more time than I had air. The point being that on a multilevel dive they can be much more different than just a minute or two. We were back on the boat after dive 2 with 1200 psi left.

But hey I am 69.8 years old. So being conservative most of the time is fine with me. If a Manta shows up at the last moment and poses for a picture I will keep the Aeris clean and take care of the mild Zoop deco on the way up.

 

[highdesert]

Two computers every dive. Primary is air integrated on a hose. Secondary is a wrist mount, same algorithm, plus an SPG. We've both been burned on expensive trips before. I wouldn't take the chance again.

 

[JohnnyC]

I never found my Vyper too conservative until I did a couple sawtooth profiles while assisting an instructor, and a different dive, strangely enough got an ascent warning when I reached up to grab a buddies GoPro that he lost control of on one of those floaty mounts. I didn't think anything of it until the next dive it put me into deco 15 minutes into the a shallow 12 meter dive. This was dive 8 over 5 days, no more than 2 dives a day, shallow reefs, max depth 15 or so meters.

My problem with the Suunto's is that they are affected by seemingly random occurrences that can significantly affect the length of NDL's on repetitive dives. Not necessarily an issue except it places emphasis on certain things like a full hour surface interval, 58 minutes will cut your NDL. A "rapid ascent" warning, which in my case was simply a rapid arm movement in a direction of lower pressure, accompanied by a surface interval just short of a full hour, affected my NDL. Once you've done one of those, it counts against you until the computer is totally clear. I don't remember reading about these in the manual, and discovered them later here in a Scubaboard thread but I could have just missed it. This is fairly anecdotal, but significant enough for me to notice.

In general it was never an issue beyond annoyance. However I could see a diver who violates their interpretation of the "rules" being unhappy with how it penalizes repetitive dives.

I now dive matching Predators as my needs have changed along with my diving. I sold my Vyper to a friend of mine and he's very happy with it. I made sure to emphasize that it would penalize poor diving habits. As a new diver it certainly helped keep him from becoming complacent. However, I think Suunto should be more straightforward with informing their customers how their interpretation of RGBM will be affected by things like rigid surface interval requirements, sawtooth profiles even in very shallow water, etc.

I dive both computers on every dive, or if it doesn't have tissue loading already, I may give one to a buddy to use and I'll bring along my xDeep BT and a set of tables for backup.

 

[Dirty-Dog]

I never found my Vyper too conservative until I did a couple sawtooth profiles while assisting an instructor, and a different dive, strangely enough got an ascent warning when I reached up to grab a buddies GoPro that he lost control of on one of those floaty mounts. I didn't think anything of it until the next dive it put me into deco 15 minutes into the a shallow 12 meter dive. This was dive 8 over 5 days, no more than 2 dives a day, shallow reefs, max depth 15 or so meters.

My problem with the Suunto's is that they are affected by seemingly random occurrences that can significantly affect the length of NDL's on repetitive dives. Not necessarily an issue except it places emphasis on certain things like a full hour surface interval, 58 minutes will cut your NDL. A "rapid ascent" warning, which in my case was simply a rapid arm movement in a direction of lower pressure, accompanied by a surface interval just short of a full hour, affected my NDL. Once you've done one of those, it counts against you until the computer is totally clear. I don't remember reading about these in the manual, and discovered them later here in a Scubaboard thread but I could have just missed it. This is fairly anecdotal, but significant enough for me to notice.

In general it was never an issue beyond annoyance. However I could see a diver who violates their interpretation of the "rules" being unhappy with how it penalizes repetitive dives.

I now dive matching Predators as my needs have changed along with my diving. I sold my Vyper to a friend of mine and he's very happy with it. I made sure to emphasize that it would penalize poor diving habits. As a new diver it certainly helped keep him from becoming complacent. However, I think Suunto should be more straightforward with informing their customers how their interpretation of RGBM will be affected by things like rigid surface interval requirements, sawtooth profiles even in very shallow water, etc.

I dive both computers on every dive, or if it doesn't have tissue loading already, I may give one to a buddy to use and I'll bring along my xDeep BT and a set of tables for backup.

I dove a Suunto Stinger for a while, and this sort of thing is why I got rid of it.
We were on Cozumel. An El Norte closed the port in the morning, but it was opened in the afternoon. The good folks at Aldora picked us up and we headed out for a two tank.
Because we started late and were trying to fit in two tanks before sundown, we cut our SI short (it was 50-55 minutes...). 40 minutes or so into the dive, my Stinger had me in deco, while the Aeris XR1-NX I was wearing for backup still had plenty of time. It wasn't a huge issue; doing the deco was no problem. It was just irritating to know that it was bogus deco caused by Suuntos insistence that 50-55 minutes wasn't enough SI. The temptation was to blow off the bogus deco, let the Stinger go into violation, and just dive the Aeris the rest of the trip. Didn't... but the temptation was there.

The rapid ascent warnings caused by moving my arm didn't bother me so much, because they're easy enough to ignore.

I sold the Stinger. I kept the XR-1NX as backup and got an Aeris Manta for primary. When I needed a multi-gas computer, the Manta became the backup.

 

[dbulmer]

As others have stated, this is typical for tech divers. I mostly dive rec at this point, but since my tech training I have always dived with two computers, even on those easy shallow dives. I think it would be very rare for someone that didn't have any tech training to dive with two. Not unknown, just rare.

I'm not a tech diver and always carry a spare d timer with me on every dive as a backup. It's not that rare in my opinion.

 

[Centrals]

I used to dive with one computer and kept the spare one on land. However, after two failure underwater, I am now diving with a computer and BT. The other computer is still being kept on land.
BTW, I do rotate the use of the computer on different trip.

Two bottom timers for tec dive and NO computer.

 

[Searcaigh]

I have dived with two Suuntos (Vyper and Vytec), the Vyper is fairly old now and in Nitrox mode always defaults to 21% after the no fly time goes to zero. Sometimes I forget about this as I used to use the Vytec as my primary computer.

On occasion I have also forgotten to change the percentage on my backup computer which has caused a lockout with it, but never stopped me diving, and I also carry tables should I really screw things up.

I now dive a Petrel 2 and use the Vytec as a backup, usually strapped to one of the floaty arms of my camera rig which gives me an alternative mounting point and on Rec dives works really nice for me.