Dive Computer or Tables - which is safer for a newer diver?

[freewillie]

No, you don't need a computer to dive. It's like my daughter and her cell phone. No, you won't die when I take it away from you, you will be just fine until you get it back. And that will be a lot longer young lady if I keep hearing quips about how old I am and living the the dark ages before they were invented. They simply make life and diving easier.

Of all the equipment we can buy they also vary in screens and display, making familiarity between models and brands more difficult. Push the button once on one brand you get depth, on another you scroll through the menu for whatever. Even though most of the regs with console SPG I rent also have a computer I still find using my own computer made life easier for me. Once my rental failed to activate in the water and then didn't start causing me to abort a dive, then another rental displayed the depth and pressure in meters and torr. Now I know my own computer and it stays constant dive to dive since it's mine even though I rent regs.

And yes, Newcastle Brown Ale is a good beer. And so is Sam Adams, Kona Fire ale, Bass, Asahi, Blue Moon, Shock Top, oh heck, just about any beer is fine with me.

 

[nimoh]

No, you don't need a computer to dive. It's like my daughter and her cell phone. No, you won't die when I take it away from you, you will be just fine until you get it back. And that will be a lot longer young lady if I keep hearing quips about how old I am and living the the dark ages before they were invented. They simply make life and diving easier.

Of all the equipment we can buy they also vary in screens and display, making familiarity between models and brands more obvious. Push the button once on one brand you get depth, on another you scroll through the menu for whatever. Even though most of the regs with console SPG I rent also have a computer I still find using my own computer made life easier for me. Once my rental failed to activate in the water and then didn't start causing me to abort a dive, then another rental displayed the depth and pressure in meters and torr. Now I know my own computer and it stays constant dive to dive since it's mine even though I rent regs.

And yes, Newcastle Brown Ale is a good beer. And so is Sam Adams, Kona Fire ale, Bass, Asahi, Blue Moon, Shock Top, oh heck, just about any beer is fine with me.

great analogy, to continue:

diving with a bottom timer is like using a phone with no memory for phone numbers (you have to remember the numbers on your own)
diving with no depth guage and a J valve first stage is like having no access to any phone and having to walk over to your friends house to chat

 

[Lopez116]

Hi Lopez116,

How did you track your nitrogen on your Grand Cayman dive?

I would use the PADI table and see what pressure group I was in after x depth and x time. We had the same routine every day. Drove to a shore dive spot (ones that had dive shops at the site), shore dove usually to 40'-50' (one dive to 60' - I think that was just north of the Turtle Farms at Cobalt Coast), lunch and beach/pool time back at the hotel. We would only do one dive per day, so surface intervals were not a problem.

The only time we dove twice in a day was our second to last day - Casuarina Point at Don Foster's in the a.m. to 50 feet (45 min bottom time; exited water at 10:30 am); then Stingray City at 3pm (max depth 12 feet).

 

[NAM001]

As an ow you dont NEED a omputer. i say this because the big thing about the computer is that it handles deco and is a multy function device. timer depth ect.... however i recommend you use one because. if you dont have a computer you have to have a depth gage and timer and tables. and since you are not likely to be diving a square profile anything you compute using the tables is a. not accurate & b. consuming so much time you can't pay attention to the improvement of skills you have been introduced to in the ow training. so the computer will be used primarily for a depth gage and nothing more for the new ow. now once you have moved on to aow and the dives are deeper you have the chance to exceed ndl on hte air you have. now the alarm is the alarm pretty handyto have. so knowing when you are reaching ndl is worth it to me to have the computer. when you start going into the deep 100-130 area and beyond you wlill get the most benifit fromthe pute, by then you have become profiecient with the basic skills of bouyancy and where is my buddy without panic and the like that you can makeuse of what the computers higher level functions can provide. I personally like the integrated computer cause it monitors the tank psi and can tell me better of time remaining based on my aiir consumption. In a way all sorts of crutches the diver can use and i still do use them, now more as a backup than before. Computers overall still have lawyers ivolved in the making of them and in my opion are extreemly conservative in the data it provides to the diver. conservativeness does not kill anyone and as such is a well conceived sole tool/crutch for the non tech diver. There are many who are disgusted by the use of them . And to those who are against them, well then good for you because that means you can mentally process yourself what the computer is proocessing. Unfortunatelly ow's donot posess the detailed levels of understanding that more highly trained divers posess again for that reason the computer is a good thing for the ow. OH one more thing..... many boat operators will not let you dive without one. If you have an accident/incident the boat needs to know if you did something wrong or not. the Chamber techs also need to know what dive prifile you did to determine proper treatment.

 

[Pane]

Personally I think when starting out a new diver should be using tables.
Learn to plan dives properly before relying on a computer.

I don't think using a computer needs to detract from planning a dive. You should know to what depth your planning to go, how long you plan on staying there, and what your turn pressure is, whether you use a computer or tables.

 

[CT-Rich]

I learned to dive on tables and used them for my early years. I would forget to set the bezel, or forget tolog exit times. I like that modern dive computers save my from my own stupidity. Easy to use, relatively cheap and reliable. I don't use it for because of the NDL (most of my dives are not going near them, but for depth and bottom time it is great. I even figured out how to set the clock on it, so now I have all the data accurately recorded in my log book. Required for every dive? No, but I spend less time worrying about all the thing computers do really well.

 

[BluewaterSail]

Many of the features that people say that they like computers for, are available on some bottom timers. I don't believe that digital bottom timers get the attention that they deserve.

These are some of the features that I like from my current bottom timer (Xen):

Downloading dive profile to a laptop/desktop when I get home
Seeing a graphical representation of the depth profile on the BT immediatly after the dive (this is cool)
ascent and decent rate
Max, current and Average depth (I really like the average depth, because that allows estimation of multilevelish dives, as 30 sec at max depth is not really indicative of total nitrogen loading)
User settable alarms which cause numbers to blink if you exceed the depth, time or whatever that you have entered

Basically, it does everything that a computer does, except NDL/deco/O2loading calculations. I honestly feel that I know more about my situation from the BT than I did from a computer.

I started with a computer, because that was what I thought I was supposed to do. I don't know how I would have reacted to a BT with only a few dives, when I was still struggling with bouyancy. Probably not very well. However, as part of research into computers, if a new diver wants to buy a computer, you could research whether it has a gauge mode, and what features are available in gauge mode.

 

[CT-Rich]

These are some of the features that I like from my current bottom timer (Xen):

Downloading dive profile to a laptop/desktop when I get home
Seeing a graphical representation of the depth profile on the BT immediatly after the dive (this is cool)
ascent and decent rate
Max, current and Average depth (I really like the average depth, because that allows estimation of multilevelish dives, as 30 sec at max depth is not really indicative of total nitrogen loading)
User settable alarms which cause numbers to blink if you exceed the depth, time or whatever that you have entered

Basically, it does everything that a computer does, except NDL/deco/O2loading calculations. I honestly feel that I know more about my situation from the BT than I did from a computer.

I just watched a review of your BT. I agree it is a very cool device, and for most of my dives it would be really cool to have. the down side is that much of the info that it gives does not replace the moost critical information that a dive computer provides. If you end up to deep being somewhat narced on what was orginally intended to be a NDL dive and find that you went an exttra 20ft, all the cool displays in the world are useless when what you really want are decmpression stops and times. you could use the old square profile and the your Dive tables to figure it out. That is a safe but crude calculation and will not be the most gas efficient measure. An accidental Deco dive implies that gas available is going to be a critical issue. I would love to dive with your bottom timer, but for $500 it is not giving me the utility that I carry the computer for. Even on my el-cheapo genesis computer, I get a graphical representation of how close I am to the NDL. For Safety, that trumps just about every log function imaginable.

I like the dive simulation feature it would be awesome for planning a complex dive profile, but again, it isn't helping with the NDL that I would value most.

But still it is a sweat piece of gear, and if you mail me one I would use it every time....

 

[Bob DBF]

No, you don't need a computer to dive with. However, it is convenient.

Nor do you need a bottom timer to dive with either. However, it is a convenient.

People have dived with nothing but depth gauge, pressure gauge and a dive watch for ages. Hell, some of the old timers didn't even need pressure gauges.

When I first started diving I used a J-valve, a capillary depth gauge, and kept a watch on the beach because it wouldn't have lasted a minute in the water. Since I had one 72 and the ponds were not really deep it wasen't a problem. By the time I started doing more aggressive dives I had a suitable watch.

I don't know exactly when it came out sometime in the '70's, but the Princeton Techtonics "Bottom Timer" was an analog, pressure actuated stopwatch for calculating time on dives. When electronics came in the "Bottom Timer" went out and now a bottom timer has a different meaning. By the way, mine still works.




Bob
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I may be old, but I’m not dead yet.

 

[Eric Sedletzky]

A while ago I got into doing some vintage diving just as a curiosity and side hobby in addition to my regular diving.
It sure forces you to think about what you're doing when all you have is a watch, depth gauge, and J valve, no SPG.
What you have to do is first check your tank pressure with a pressure checker before the dive to make sure your tank is full. Then you must pay attention to your time and depth and you must also have an idea of your air consumption rate so you will be contantly calculating mentally how long you've been down and the average depth which will give you an idea of how much air you've gone through and how much you have left.
There's also the factor of working harder underwater for a give reason which uses up more air.
I've got it down to where I'm already almost back at the beach doing a stop when I need to pull the J valve so I guess I'm doing OK.

Then there's the DIR group which are the best trained and best overall divers on the planet. They don't use computers (last time I checked). They run tables in their head and have a system where they depth average and do a series of mandatory deep stops on every dive. I've never heard of one incident of any of them getting bent. They can also recalculate dives (mid dive) on the fly if needed.

For shore dives in Socal a computer isn't really necessary.
The size of your tank will pretty much determine your dive time, and doing shore dives with a single tank it would be almost impossible to get into deco.

Computers are a nice gadget but in my opinion not absolutely necessary and I can think of many other things to spend the money on.
However, If I was an international jet setter going on lavish dive vacations on liveaboards all over the world like some lucky folks on this board I would invest in a good computer.

I currently do not have a computer. I use a bottom timer and run tables in my head. For the diving I do that system is perfectly suitable.