Is a computer actually necessary?

[Air On]

Then... and Now...


Started reading all the posts.. when Bla bla bla and jumped to the end...

As Obviously stated by people. No a Dive comupter is not a required item.
Depth Gauge, Air Pressure, A timer and your version of the dive tables...
That is the minimum I'd use.

All the divers I had known prior to getting certified we all old schoolers. Half of them used the Navy tables still. I was of a mind that no batteries and no electronics was best in the water.

After taking the classes under NAUI and being required to dive my tables (invaluable skill) I liked the computer as a backup idea and invested in one.

After using it on my first dive trip and all the on boat confusion... I wouldn't dive without it unless I had to. I was manualy tracking all my dives and trying to plan ahead... But one mistake early in the weekend and you can scew up your entire trip.

Conversly having the manual backup incase the computer fails, floods, etc... is a trip saver, otherwise your out of the water for and extended period to reset your residual nitrogen level.

The non-flat dive calculation of the computer is very nice. If you dive on tables and hit you deepest depth then come up to under 20 feet and hang out for the balance of your dive, say 45 minutes.
The table time is at the max depth for the entire time. You just lost the night dive that is sheduled on some dive trips.

On the computer it actually registered you as off gassing at an increased rate while you were watching fish and hanging out at 15-20 feet... The Nitrogen load from hitting max depth is decreased durring the durration of your swim. Now you can safely get in an extra dive or 2 that day...

With a dive computer you can download it and add in lots of other data like your equipment and weights used, dive buddy, etc.

I found that reviewing the dive profile fater I got home was a learning experience in itself.
I could clearly see how my air use changed at depths and temps. I could see at what depth the temps changed. I could see if I surfaced too fast when surge pushed my over a rock out cropping.

I know some people who said that the computer flashing, vibrating and alarm beeping saved them problems when experienceing a mild narc euphoria and not watching the clock.
I know another diver that credits her computer for saving her from running out of air due to getting so entranced taking pictures of fish when it started chiming.

Now they have some computers with extra features... you can keep an eye on your dive buddies info too. No hand signals, no dive slate... just hit the button and you see their dive data like it was your own.

I wouldn't say DEPEND on your dive computer... Still keep a manual log and use your tables as a backup and emergency manager. But the tools and benifits of a dive computer can really enhance your dive experience.

Personaly I have a Sunnto Cobra 2... Its a console not a wirless wrist one. Its batteries are USER REPLACABLE. Thats a pretty big deal for many dive computers. The only thing I hate about it is the digital compass. It has to be one of the stupiest more poorly realised tools on the unit. I added the manual compass head, that I much prefer anyhow. So I don't think there is anything i would change on my dive computer.

Its a tool like anything else, use your brain first and employ the tool to help you. Not take over for you. It can be abbused or it can enhance your dive experience...

In the end its user preference... I like the added tools a dive computer has to offer.
And like I said, I manualy track my dive time with a backup watch and dive slate with my dive tables on it. I just need to find a back up depth gauge and pressure gauge... Then I'll be a happy redundant diver.

So worst case... you keep your manual console, then add a wireless dive computer later and have a nice redundant tech diver rig later. Win Win.

 

[Cudabait]

As to the first paragraph above, I would submit to you, gentle readers, that the exact opposite is true. If loaded with the proper model, such as Bruce Wienke's RGBM in the HS Explorer, the micro-processor can, through its sensor inputs, track your exact position in the water column extremely accurately. It can then do calculations based upon that information MUCH faster than any human can, thereby offering real-time decompression computation that no human can duplicate. (If there is such a person with that kind of arithmetical speed, he or she should immediately apply to Dr. Xavier's Academy!)

As for the second paragraph above, the RGB model, for instance, has already gone through that "crash test dummy" phase. The good folks at NAUI have done literally thousands of dives in order to provide the kind of anecdotal responses needed to refine the system and provide verification for it.

I would submit that most of us do not wish to be in the position of experimenting upon ourselves and coming up from a dive saying: "Aiee, doc, that one really hurt! Can you...gasp...tweak it some more!":wacko:

Rob Davie, AKA BigJetdriver, died while using a computer assisted rebreather. A computer is a machine, further, it is a machine based on table formulations. So, keep track of your time and depth independently of a dive computer.

Yes, many shops are insisting that their instructors make a sales pitch introduction to computers during class sessions. Some are taking it a step further and including a computer on th shop's equipment that is taken to Open 'water Classes.

By the way, Rob was a good friend.......RIP.

Regards,

 

[Web Monkey]

Anyway, i was just wondering what she meant by "this is not my opinion", so i was wondering if any user of this board has any concrete proof that computers are actually "safer" than a divetable/depth gauge if the former is used correctly? Thanks

Dive computers are a lot safer if you're a really inattentive diver, since your tables won't scream "You're going up too fast!" or "You're running out of air!"

If you watch your air, time and ascent rate, the tables might be safer (or not), depending on which tables you're using and how you're diving, or which computer you buy.

Some computers are more conservative than some tables and some tables are more conservative than some computers. Also computers take your profile into account, while the tables don't which may be a good thing or a bad thing depending on whether you dive a square profile and which table or computer you pick.

Of course, the real answer is that the shop owner would have sold you solid gold weights if he/she thought you would buy them.

Terry

 

[emttim]

Ok here's the story, i was taking the last pool session in my OW class when a new instructer, who was also the owner of the shop (not my original instructer) tried to force me to buy a dive computer when i ALREADY had a depth gauge, and a dive watch. She said that people who use depth gauges are "stupid" and she insinuated that computers are "safer" okay so i respectfully told her that was her opinion, and she arrogantly said that that wasn't her opinion.
I didn't like her attitude (she had been pretty awful to me a few days before this) so i just got up and left.
Anyway, i was just wondering what she meant by "this is not my opinion", so i was wondering if any user of this board has any concrete proof that computers are actually "safer" than a divetable/depth gauge if the former is used correctly? Thanks

That person sounds like a real piece of work. Not only would I not believe her, but I would never do business with that shop again if she's the owner.

The dive tables are meant to be used with just a dive watch. Honestly, the tables by themselves probably are safer if you stay on top of them since they kind of "cheat" you out of some bottom time which obviously reduces your nitrogen exposure.

 

[Air On]

Rob Davie, AKA BigJetdriver, died while using a computer assisted rebreather. A computer is a machine, further, it is a machine based on table formulations. So, keep track of your time and depth independently of a dive computer.

Yes, many shops are insisting that their instructors make a sales pitch introduction to computers during class sessions. Some are taking it a step further and including a computer on th shop's equipment that is taken to Open 'water Classes.

By the way, Rob was a good friend.......RIP.

Regards,

I'm sorry to hear about his passing, I hate to hear when divers are lost...

That being said the issue would be the fact he was on rebreather, not the fact of a dive computer falure.

Look at the stats, talk to DAN...
% of people on regular scuba with computers and accidental deaths,
VS
% of people on Rebreathers and accidental deaths.
(include the fully closed and semi closed systems.)

Rebreathers are more complicated and more prone to issues, even when used by experts.

Scuba is potentialy fatal to start with, we have to acnologe that risk... The more complicated your equipment, the more Mr Murphy has to work with in ruining your day.

Many of the fun things in life do have risks... Thats part of the attraction though too.


As far as shops selling you equipment, thats their job, you walk into a car lot you bet your butt someone is going to try to sell you a new car.

That is NO excuse for talking down to students or customers, thats no excuse for saying people are stupid for not diving computers... Thats an opinion and the sales person should be more professional. Try another dive store and see if you can find a shop with better staff.

My opinion, you should learn both types of equipment, so you are more farmiliar with it.
For all you know your next dive buddy my have difernt equipment then you...
Hell even dive computers all interface differntly... can you read their gauges and understand them?

"Stupid" would only apply to not making sure you understand how both of your equipment works. What is their second air source, does it work properly, how does their BC work, how does it float, etc.

If one of you needs to rescue the other and you can't figure out their equipment... Thats a big problem.

I've had repeated issues with boat issued dive buddies who didn't take the time to look and understand the equipment first then had a problem later.

One guy didn't even know how to read the borrowed dive equipment he had on to see his depth OR AIR!!! I asked him before the dive and he was dismissive that he was cool. Then part way through the dive I asked air level and he couldn't read his own equipment! It was a dive computer, it was clearly visable if you had taken time to look at it before diving... as it was I ended up trying to teach him to read the gauges on his equipment at 40'... Not very cool.

 

[Air On]

That person sounds like a real piece of work. Not only would I not believe her, but I would never do business with that shop again if she's the owner.

The dive tables are meant to be used with just a dive watch. Honestly, the tables by themselves probably are safer if you stay on top of them since they kind of "cheat" you out of some bottom time which obviously reduces your nitrogen exposure.

I think a watch (timer) and depth gauge are the bare minimum.
Though an air gauge would be pretty nice to have to make sure you don't run out.

Without knowing your depth, you can't refence the tables by time alone unless you just assume 100 feet and know you couldn't go deeper then that.

 

[emttim]

I think a watch (timer) and depth gauge are the bare minimum.
Though an air gauge would be pretty nice to have to make sure you don't run out.

Without knowing your depth, you can't refence the tables by time alone unless you just assume 100 feet and know you couldn't go deeper then that.

This is pretty obvious, but if you use a computer like I do, you're not going to think of depth gauge as being a separate gauge since it's one of the pieces of information that your computer gives you. Hence me accidentally omitting it.

 

[Papa_Bear]

It's really hard to get on the internet, but I say go for it!

Why would anyone dive without one these days? If your interested in going backwards I have an old horse I will sell you, it gets great gas millage!

The computer is the best thing to ever happen to diving! Use two!

 

[Aquatic Eagle]

Ok here's the story, i was taking the last pool session in my OW class when a new instructer, who was also the owner of the shop (not my original instructer) tried to force me to buy a dive computer when i ALREADY had a depth gauge, and a dive watch. She said that people who use depth gauges are "stupid" and she insinuated that computers are "safer" okay so i respectfully told her that was her opinion, and she arrogantly said that that wasn't her opinion.
I didn't like her attitude (she had been pretty awful to me a few days before this) so i just got up and left.
Anyway, i was just wondering what she meant by "this is not my opinion", so i was wondering if any user of this board has any concrete proof that computers are actually "safer" than a divetable/depth gauge if the former is used correctly? Thanks

Wow, she sounds like a lot of fun. Time to find a new shop.

 

[RiverRat]

Shops can get really whacky when they can't sell you on something. I had split fins force fed to me several times but I never bought them. Same with weight harnesses. I got accused of "bragging" about how little ditchable weight I dive. Over the shoulder looks in the pool about "user modified gear" direct quote from the PADI manual about my backplate and wing setup. Accused of having "incompetants tamper with the internals" of my Apeks when they thought I rebuilt it and sratched the seat LOL. FYI I rebuild my own now for years, no issues.

You have a few options as I see it:

A: Dive tables with a timing device. It won't hurt you if you do it right and will enforce good dive planning practices. You buy buy a computer later on down the road if you wish.

B: Buy something like I did, a Suunto Vyper that you can use as a computer or bottom timer in Guage mode. I'm taking a tech class now and all I have to do is switch modes.

C: Buy a nice bottom timer and use a watch as backup.

If you decide to go the GUE/DIR route then you won't need a computer.
If not then a computer is fine for recreational dive profiles as long as you dont soley rely on it for planning and diving your dives.