Are dive computers required equipment now?

[spectrum]

I learned to do math, than to use a calculator and then to use a computer as the evolved duting my lifetime. My kid's followed the same progression.

There is no reason why a new diver should need to invest in a computer from the get-go. There may very well come a time when a persons diving will be enhanced by diving with a computer and if the diver is qualified they will know when the investment is appropriate. Bought early it's just tied up money going obsolete and waiting to get lost or damaged before it has the chance to be of value. Worse yet it is a crutch that leaves the diver blind to the fundamentals behind the computer and left at it's mercy.

I've had a few repetetive dives that warranted consulting tables and that was sufficient to manage those times. When your dives begin to push the boundaries of the tables that is probbaly a common trigger point to invest. If you do frequent multiple boat dives you may get there quicker. If all of your diving is modest shore diving it may never make sense.

Like anything else where the is $$ there will be those who seek to sell. Understand what the tool will do for you and buy it when you need it.

That's my 2 PSI
Pete

 

[mark99]

same thing that happened to chopping down trees with only an ax

it's just a lot easier to plan your dive and dive your plan using a computer

I fear that many people with only a computer just rely on the computer exclusively, and plan the dive on the fly depending on the no-stop time remaining at any given point in the dive. At the risk of sounding a little like a geek, I was checking my plan with tables, but recently started using the PADI "Wheel"- it is actually quicker and easier to use than tables, and can be used for multilevel dives (within certain restrictive rules about what depth levels can be used). It's particularly faster than using the computer on the boat for planning the second and third dives after the first, when you would have to input your SI and proposed depths to scroll thru your no-stop times in the dive planner. Of course I still follow the computer no-stop time as the final determiner of my time limits, but the plan at the surface gives you a better idea of what the actual dive should be.

 

[H2Andy]

I fear that many people with only a computer just rely on the computer exclusively, and plan the dive on the fly depending on the no-stop time remaining at any given point in the dive.

i am afraid you are right...

my plans are based on air consumption, so the computer is really a secondary
tool for me, mostly used as a depth gauge (and yes, NDL's come into play,
but they are usually not a factor at the depths i dive (usually less than 80 feet)

am a newbie, and i can't do the deco-on-the-fly that some of the
more advanced divers do... i just use air use as a turn-around plan.

for example, at any given depth, my plan is to turn around when
i hit rock bottom. rock bottom is dependent on what kind of diving
i am doing (1/3's usable, 1/2 usable, full usable) and so on.

i find that gas, not time, is the major factor at my level of diving

 

[String]

Requiredno but they are a useful tool. Even if you dont use the decompression stuff on them theyre great for logging.

I agree with the posters saying tables first andwould recommend new divers NOT get them immediately. Practice using and understand the tables, practice making ascents (its amazing how many divers ive seen that CANNOT ascend properly without a computer bar graph to help them) with an analogue gauge/watch and get the skills in place. That way you'll understand what a computer tells you and very importantly,WHY.

Having a firm understanding of the theory and practice is invaluable for sanity checking a computer and making a diver aware of the situation. Oh, and useful for when the computer breaks.

My main worry are new divers whove only used a computer wouldnt really appreciate the theory behind all that and follow it blindly whatever it says.

 

[baltimoron]

Most of the Diving I've done is sans computer, though then again, most of the diving I've done has been shallow enough that all I need is the tables.

 

[Trisha]

Hmmm.... seems like when I first started reading ScubaBoard, I constantly found posts on "computers vs. gauges." Just now I looked on the "Computers, Gauges, Watches and Analyzers" forum and went through nine pages before finding a thread on the debate! I guess computers won the day.

So on your question: do you need a computer? No.
Should you spend the extra money on a computer vs. gauges? It depends.

Computer pros:
An active system which literally has bells and lights to signal you when you are doing something screwy (rapid ascents, pre-set depths, if air-integrated it signals for low-on-air and turn-around air supply.)
A dive profile based on real-life data, not dive tables.
Dive log storage and retrieval.
Dive planning profiles created and tweaked on dry land.
In the event of failure the computer stops giving information -- in other words, you aren't diving a broken depth gauge (as my husband and I did with two different rented rigs -- never used that LDS again!)
Computers can be purchased air-only or Nitrox-compatible (if you think you will ever need it, go with the Nitrox unit.)

Computer cons:
The expense -- but wait! Check ScubaToys and your LDS and compare a submersible pressure gauge (you'll need it if the computer isn't air-integrated), depth gauge, timer and compass vs. the spg and an air-only computer and compass. It may surprise you how close the costs are.
The batteries -- yes, batteries are a failure point, both in them going dead and in flooding your unit. Some computers must be shipped back for battery replacement, others can be done on the spot or at your LDS. But again, if there is a problem you know right then.
The laziness factor -- now this is a failure to understand the situation. And computer users can be lazy, by not planning the depth and time, not watching their air consumption, not building a fudge factor into heading back to the surface or back to shore. But so can gauge divers. And gauges are a passive system, which means you can breath out most of your air, overstay your welcome at depth, and be none the wiser. Both are diver error, not equipment error.

Both gauges and computers should be inspected annually. Remember my rented gauges? We went to a marked spot at 25 feet -- my husband's depth gauge said 20 feet, mine about 15 feet.

All things being equal, I'd do what we did again -- practice our first dozen or so dives on rented gauges, and save up for computers. Good luck.

 

[spectrum]

Compare a submersible pressure gauge (you'll need it if the computer isn't air-integrated), depth gauge, timer and compass vs. the spg and an air-only computer and compass. It may surprise you how close the costs are.

Surrendering those functions to a single electronic device IMO is not an option. The computer should be in addition to analog instruments. It's too easy to hear of floods and other outright failures beyond batteries. In reading threads it's easy to find divers wearing a back-up computer for this reason.


Pete

 

[lostinspace]

I dive with a wrist computer, wrist compass, wrist digital watch (running out of wrist space!) and a combined depth / air gauge.

I am comfortable with my air consumption - I do a mixture of boat and shore/jetty dives, and I know the profiles I am comfortable with to depths I am comfortable with. I have never gone deeper than 39m. I feel uneasy going deeper than 30m, and obsessively check my depth gauge & computer at the same time around this depth. Why? Because I know my air consumption increases, as my ND time decreases, at these depths.

I like the flexibility of computers. You can dive with a plan, but tables can be too rigid. I make sure I dont dive saw tooth profiles. Yes, things can go wrong - but that is separate to computers or gauges.

I like using both. I hold my depth/air gauge in my left hand and wear my computer on my left writst.

I have to say - my air consumption is pretty low - I can do >70 minute dives on a 12L air tank. But I always plan dives to be no more than 45 minutes. Mainly because the shore/boat watch have been told that time and I dont like to panic them.
But.... whilst I was taught tables in my training, and I know how to use them, I dont use them to plan my dives. I also have at the front of my brain and have agreed with my buddy (my husband) that if one of our computers ever fails, we immediately surface and stay on surface for 24 hours. Even if the other's computer says ok. Because we still get slightly different times & profiles on our computers (same brand, just different eg depths, time at depth, whatever).

We never ever dive "trust me" dives. Even when we trained.

I also dive 3-4 times per day - you cant do that with tables, and you can with a computer - but..... I always listen to my body. I know it well. I know when I am getting build up of nitrogen. A headache, overly tired/achy, a bad night's sleep.... and then I de-gas for 24 hours.

 

[TX101]

No, a computer isn't "required".

But neither is a BC. Or an Alternate air source. Or an SPG.

But they do make life a lot easier.

 

[Trisha]

engdiver, hope you're enjoying the information. Actually, if you do a search on this the early debates were pretty intense.
Since you have a background in gauges you know the rationale on using tables. You might even remember the "60 feet/ 60 minutes" guide from the U.S. Navy no-decompression dive tables. I like the U.S. Navy tables because I can easily remember them on the fly -- 50 feet/ 100 minutes, 100 feet/ 25 minutes, etc. When time is critical, it can save your bacon not to fumble for a chart (mine are in my dive log, anyway.)
The important part is knowing that all dive tables are theoretical (uber-athletes under controlled conditions) and the U.S. Navy tables in particular are way too liberal for us couch potatoes. So compare tables and go conservative on maximum no-deco times, then build in a fudge factor. This is suppose to be fun -- time in the hospital is not a joyful bonus.

While we're on this, borrow a current beginning scuba book and look up the factors that predispose a person to decompression illness. Note that all but one are preventable -- age. After 40, higher theoretical risk.
But the Cousteaus all look good in neoprene!

spectrum wrote: Surrendering those functions to a single electronic device IMO is not an option. The computer should be in addition to analog instruments. It's too easy to hear of floods and other outright failures beyond batteries. In reading threads it's easy to find divers wearing a back-up computer for this reason.

Check your instruments early and often. Again, analog has messed up on me, and I would not have known it if my husband and I weren't at a premeasured depth with two different readings.

lostinspace -- I like how you think. It's not just plotting a given depth and time with the tables, it's agreeing on Plan B and Plan C if things go wrong. Instruments are just tools, but they don't take the place of the air-integrated computer between your ears!