SPG vs. Air Integrated

[RiotNrrd]

I'm not as senior a diver as many others on this board, but I'll tell you what I do:

I carry a Oceanic AI computer as my primary;
A DiveRite SPG as my secondary for air, and;
A Citizen Aqualand dive watch as a secondary depth gauge and timer.

This way, I figure I'm pretty redundant without a huge amount of bulk.

The one negative I've had is that I tend to NOT set the bezel on the dive watch, B/C I know the water-activated functions of the watch shoudl capture everything... but that's not really a good excuse, and something I need to work on. Beltaed 2006 resolution?

RiotNrrd

 

[dl348]

I personally use the Suunto Cobra as well. It is larger than the analog SPG, but it's only because I have the optional compass mounted on it.
I can't see how your friend thinks it's easier to read an analog gauge over a digital readout. The digital readout, in my opinion, is more accurate and easier to read.

 

[MrConclusion]

The way I look at it, an air-integrated computer is sufficient for most recreational diving, as long as you have halfway-decent awareness of your air supply. In other words, I woudn't want to be the type of diver who neglects to check gauges for 20 minutes, only to find that the digital has failed or (even more rare but worse) is displaying incorrectly.

After all, if your (air integrated) computer fails, you're going to thumb the dive, right? Plus, I haven't seen any real data on comparative failure rates between traditional analog SPGs and AI computers. There's some kind of balance to be found between the safety of redundancy, and the additional failure (possible HP leak) points of adding another hose, spool, and gauge.

I wouldn't want to do be under any kind of decompression obligation, or even a limit-pushing recreational dive profile without an analog gauge or AI computer that I trusted implicitly, and perhaps both would be better.

 

[JimC]

Less is more

 

[John C. Ratliff]

My "buddy" and I are having this "discussion" -- she's becoming a "mindless DIR lemming" (her phrase) and wants to be as "DIR Compliant" as possible.

We both have Cobra air integrated computers as well as Mosquitos. As a recreational diver, she has no desire/intention of giving up her Mosquito to be totally "DIR Compliant" -- but she wants to replace her Cobra with an SPG. As far as I can tell, the two reasons are:

1. The Cobra isn't "DIR" and gives her too much information -- i.e., it will display remaining air time in addition to NDL's and remaining pressure; and

2. An SPG is analog and it is easier to tell at a glance approximately how much air she has left because the arrow is easier to read than the Cobra's digital readout.

...I'd like to hear the pro's/con's of having an SPG plus wrist computer as opposed to wrist computer plus air integrated computer...

Peter,

First, take a look at this thread in the "Accidents and Incident" area:

http://www.scubaboard.com/showthread.php?t=124299

This will give some perspective on the "tables" verses diving computer ways of computing decompression/no-decompression limits.

I have been a "vintage" diver for many years, and used tables and a watch. But I am also working in the semiconductor industry in safety, and decided just before Christmas to enter the computer age for my diving. I initially decided on the Mosquito, but then was presented with a Seiko Diving Watch by my son, so I went back to the LDS, and picked out a Cobra dive computer. I like the air integration feature, as I will be using it to measure swim fin efficiency this coming summer is tests I hope to complete.

You have the best of the digital age. Having a Mosquito and a Cobra gives you the redundancy, and after reading over the Cobra manual, you can elect to see only the depth/time/pressure information (Gauge Mode). The Cobra will still record all the other information, but you don't have to see it (this was aimed directly at the more technically oriented divers).

Since you are recreational divers, you really don't need the redundancy of a SPG. The SPG is not as accurate as the Cobra will be, and can also be messed up by mechanical damage, so it's not fool-proof.

After using the Cobra for a number of dives, your buddy diver will get to know her air consumption rate and be able to predict how much air is still left for a given dive. We used to do these calculations by hand, and now it is much easier to do.

I think you should encourage her to read these entries, and continue to dive the equipment she has. To me, it makes no sense to go down a step to an SPG, when the Cobra is already available. Also, you will loose some money making the change, and for no reason at all.

SeaRat

 

[dpthdiver]

I have dove both for many years and I have had more problems with a SPG than I have ever had with any computer. It's hard for me swallow the "in case my computer dies" theory. Depending on the computer, this shouldnt' be an issue. I have never had a computer or transmitter problem ever. I've worked at a shop for quite a while and have never heard a "my computer died" story. Now there are exceptions out there, for example your cheapos. I'm not talking about them and I don't advocate diving with them. I HAVE had 3 SPG failures in the last 4 years. There is nothing like the feeling of teaching in a pool with a gauge showing 1200 lbs and then run out of air. Embarrasing. Is it a good idea to have both? Sure. Is it a good idea to have 2 computers? Sure. Whatever way you go, don't place complete faith in either one and have a emergency plan for failures. From my dealings in the past with SPGs, I can no longer trust them, won't trust them and therfore I replaced them.

 

[StSomewhere]

Don't assume a digital device is perfectly accurate or even all digital. A couple of you mention the analog SPGs can stick or start to be inaccurate. But that digital SPG is reading an analog measurement that is just being translated to a digital signal.

(In the interest of disclosure I owned a Cobra for two dives and hated carting the damned thing around so much that I begged my LDS to let me trade it in on a Vytec, sans AI.)

John

 

[jeckyll]

Peter: I would say one of the biggest pro's is that your buddy (who shall of course remain unnamed) is that she feels more comfortable with that setup.

I would say that given that she's going down a perfectly "safe" road (i.e. she's not suggesting throwing out both computers and not bringing a bottom timer or table or spg) why not ebay the cobra and let her enjoy her new direction?

Maybe my approach is too simplistic.



Bjorn

 

[Divmstr223]

for over 10 years I have been diving with a SPG....I have ordered the Suunto Vytec as I am looking for a good wrist computer with air integration. I've heard positive feedback on this computer so I'm pretty excited about it. But, just to be on the safe side, I will most likely dive with my SPG for a few dives as a backup and comparison....

 

[KOMPRESSOR]

Less is more

Absolutely!

And may I add: Keep It Simple Stupid! (K.I.S.S.)


For my own choice I've crunched no less than two consoles. Now I dive W/BP only, and will never have a console again. I am not a "DIR" rat. Neither educated or trained for that. But I appreciate the "Hogarthian" approach to diving gear. I has really, really given more quality to my diving time because it's so much easier to swim around without all the drag of bulky stuff.