Why should I get a computer?

[Doctor.Lizardo]

My apologies if this sounds like a stupid question but why should I bother getting a computer? I'm returning to the sport after a long hiatus and it appears that computers have now become ubiquitous, bordering on mandatory for many folks. I've done many thousands of dives through the 70s and 80s, none with a computer, and I didn't die My understanding is that computers typically allow one to dive longer as the algorithms factor in depth over the entire dive, rather than simply using one's maximum depth as is normally done when using the tables... but I'm not sure how much more time one would get and whether it's worth it. Or is it just a matter of convenience for most folks?

 

[El Orans]

It's useful as a log.

 

[The Chad]

If your doing completly square dive profiles at sea level and not doing deco or gas changes and know how to use tables for ML dives, maybe you don't need one. They are handy though with the other things listed above

 

[BradEllis]

My understanding is that computers typically allow one to dive longer as the algorithms factor in depth over the entire dive, rather than simply using one's maximum depth as is normally done when using the tables... but I'm not sure how much more time one would get and whether it's worth it. Or is it just a matter of convenience for most folks?

Your understanding is right on the money. They are just a convience for lots of divers, esp those that ONLY do very shallow (less than 30') dives once or twice a day when they are on vacation.

However, they do use algorithms that factor in depth over the entire dive as you have stated. This equates to much longer bottom times when compared to using a dive table and a square profile. The real difference starts to show up on dives deeper than about 50'. By starting your dives at the deepest point of the dive site, and then gradually working your way shallower as the dive progresses, you really take advantage of the computer algorithm. I frequently have bottom times longer than 45 minutes on dives where the deepest depth is 100' or so. As a matter of fact, I just returned from a week long liveaboard trip to the Florida Keys where we were doing 5 to 6 dives per day. Depths ranged from 35 to 130' and I didn't record a single dive shorter than 50 minutes the entire week. Thats a true testament to the advantages a dive computer gives you.

Brad Ellis

 

[Doc Intrepid]

My apologies if this sounds like a stupid question but why should I bother getting a computer? I'm returning to the sport after a long hiatus and it appears that computers have now become ubiquitous, bordering on mandatory for many folks. I've done many thousands of dives through the 70s and 80s, none with a computer, and I didn't die My understanding is that computers typically allow one to dive longer as the algorithms factor in depth over the entire dive, rather than simply using one's maximum depth as is normally done when using the tables... but I'm not sure how much more time one would get and whether it's worth it. Or is it just a matter of convenience for most folks?

It isn't a stupid question. There is no doubt that newer divers are conditioned to want to run right out and purchase computers.

As others have noted, whether you 'need' them or not is pretty subjective. If you're traveling to a dive destination, doing 3-5 dives per day over 7 or 8 days, for example, a computer can track residual nitrogen much more precisely than diving without one. If you're doing a lot of multi-level diving they allow you greater precision in tracking ongassing, thereby increasing your allowable times.

OTOH, if you're dropping off a dive boat onto a wreck, which is a reasonably square profile, then you've likely already planned out your gas plan and you're pretty familiar with your gas requirements.

Whether a computer is worth the investment or not is really something thats in the eye of the beholder. I've been diving since 1975 or so and have never owned one. I log my dives using a ballpoint pen. Its never bothered me, frankly, however, Brown University annually publishes a little blurb for its faculty to orient them to incoming freshmen. The freshmen entering Universities this fall, for example, have never known a time when personal computers were not widely used. Many of them have never seen a cassette player. They have never lived when bottled water or cellphones did not exist.

To some extent dive computers are widely used simply because they exist, and not because they provide any specific 'value-added' to the experience. As you note, many older divers have gotten along for years without them and are unable to articulate any compelling reason why they should run out and drop $500 or so on one now. It's primarily another personal choice, for most recreational diving, unless your specific diving circumstances are such that the computer actually provides a measurable benefit for the diving you're engaged in.

IMHO. YMMV.

Regards,

Doc

 

[Rick Inman]

I have a computer, but I use it in gage mode. I may go back to using a computer if they ever teach it to know:

How old I am.

How fat/slim I am.

My physical conditioning.

How I'm feeling that particular day.

How hydrated I am.

How cold/warm I am in the water (not the water temp).

My average depth.

Programmable stops.

How much I exert myself during the dive.

Make a good Mocha Latte.


Until then, I'll just stick with the one between my ears, which does know all that and knows how to make a good latte, too.

 

[Puffer Fish]

Some good answers, but also consider this: If you breath nitro, which is a very good idea if you are doing the 60 to 100 ft diving, and you are switching gasses with tanks, the tables get fairly complex.

If you have an air integrated one, you also get some very important information... like SAC rate for future dive planning.

As El stated, you get a very nice record of your dives.

If you travel a lot (looks like that would be the case), you don't always exactly know the profile you will dive. The computer takes care of those nasty reverse profiles, the gradual incline ones and some of the complex ones...they are worth the money, many times over.

Dive in the same place, square profile.. don't need it.

 

[Puffer Fish]

I have a computer, but I use it in gage mode. I may go back to using a computer if they ever teach it to know:

How old I am.

How fat/slim I am.

My physical conditioning.

How I'm feeling that particular day.

How hydrated I am.

How cold/warm I am in the water (not the water temp).

My average depth.

Programmable stops.

How much I exert myself during the dive.

Make a good Mocha Latte.


Until then, I'll just stick with the one between my ears, which does know all that and knows how to make a good latte, too.

Mine did ok, until you got to the Mocha Latte.. but it does really well on all the other items (most have adjustable settings)

 

[Rick Inman]

Mine did ok, until you got to the Mocha Latte.. but it does really well on all the other items (most have adjustable settings)

Really? You can put in your age and how you feel and how hydrated you are? Cool. What kind is it?

Here is one guy explaining how computers tell you when it's ok to fly: POST

Here's another telling you how he does it: POST

 

[nereas]

The main advantage of a computer is that it gives you a dive planning feature which allows you to plan your bottom times for various depths on repetitive dives, for air or various nitrox mixes.

For relatively shallow dives in the 50 ft range, you can probably ignor this. But if you are diving in the range of 75 to 100 ft or more, this is really nice. You press a button, and there is it, in real time. If you want to wait longer, you can input more planned surface interval time, then press a button, and there is the new number.

The second main advantage of a computer is that it calculates a very precise average depth per dive. This allows you to track your SCR.

The third advantage is that they have an ascent rate monitor built in, and they will beep and thus warn you to slow down if you are ascending too fast.

The final advantage, as others have said, is that it records a lot of data for you, such as max depth, current depth, dive time, profile, water temp, etc. This info can then be transferred into your log easily.

For old salty divers, the computers take the place of the watch and the depth gauge and eliminate the need for dive tables to plan repetitive dives. I dove for a long time with a watch and an analog depth gauge, until the computers became very reliable and sophisticated around the late 1990s. Then I finally bought a SUUNTO.

Boat captains, these days, look for 3 things most often on divers: (1) a surface marker buoy rolled up and attached to your B/C-harness; (2) a dive-alert horn attached to your LP hose; and (3) a dive computer. If you have all 3 then they are usually pretty happy with you being on their boat.

When I dive trimix tech deco, I switch the computer into to gauge mode, attach it to a bottom timer as a backup, and use that for square profile deco diving.