Computer or Not

[ChrisA]

I've never used one. My buddy that is just getting certified is getting a real nice computer. I was just wondering how many of you use them, and how necessary you think they are.

If depends on the type of dives you do. If you are doing one non-deep shore dive where you know you will run out of air before NDL then you don't have much need for a computer. But as soon as you are doing multiple dives or multilevel dives the computer will let you spend more time underwater as the dive table assumes an unrealisticaly conservative dive profile.

With a computer my typical weekly Weds.night idive is to go to 70 or 80 feet untill I use up most of my NDL and then work up to shallower water slowly. By the time I'm back to 40 feet of depth I've got over and hour of NDL again. then I'll hang out at 30, 20 and 15 feet untill the air gets low. A dive table would have had me out of the water with a half tank of air left But with a computer I can safly go to 80 feet and stay down for an hour if I want.

Also if your buddy has a computer his is going to want you to have one too because you will have to dive the most conservative plan. He will not want to dive on your table based plan because it will force him out of the water when he could have stayed for 30 more minutes.

In my case a dive costs me just an airfill but if I'd paid for airfare and a boat the extra time the computer buys is valuable makig the computer a no-brainer.

 

[Zeeman]

don't need it, but it sure makes life easy

Z...

 

[rjack321]

Fair enough.

I've never used a computer in the past 18 years of diving, and haven't found a need to get one. I picked up a Mosquito for my wife a while back because she thought it was cool, and she no longer uses it. A digital bottom timer seems to work easier for us, and I've never had a problem tracking CNS % and OTUs over the course of a week or more of diving.

~ Jason

Are you actually calculating CNS% and OTUs on a regular basis? I did for awhile and eventually decided that for any reasonable combination of diving there's almost no way for me to reach even close to their limits.

If I had 5 dives planned per day for multiple days (liveaboard?) or wanted to get a couple of tech dives in per day, I might start tracking this again. Maybe if I went to the Red Sea or something :07:

 

[limeyx]

Are you actually calculating CNS% and OTUs on a regular basis? I did for awhile and eventually decided that for any reasonable combination of diving there's almost no way for me to reach even close to their limits.

If I had 5 dives planned per day for multiple days (liveaboard?) or wanted to get a couple of tech dives in per day, I might start tracking this again. Maybe if I went to the Red Sea or something :07:

well, bottom time * /2 isn't so much work I guess

 

[darkpup]

Are you actually calculating CNS% and OTUs on a regular basis? I did for awhile and eventually decided that for any reasonable combination of diving there's almost no way for me to reach even close to their limits.

If I had 5 dives planned per day for multiple days (liveaboard?) or wanted to get a couple of tech dives in per day, I might start tracking this again. Maybe if I went to the Red Sea or something :07:

Not anymore. I tracked our CNS % and OTUs for the 3 day Channel Islands trip we did, and with 5 dives per day, we never got close to the limits.

I hear you on the Red Sea trip. If you'd stop putting the bug in Janeane's ear about that Cave class in Mexico, then we should be able to do a Red Sea trip next year. Multiple dives to 150' for 20 to 30 minutes (without the use of a computer) would be a blast.

~ Jason

 

[MoonWrasse]

A dive computer should really be the first piece of gear a new diver should purchase.

I disagree.

I'd suggest buying a safety sausage and whistle first.

 

[1_T_Submariner]

I use computers. I maybe wrong but it seems that they are the most useful when doing dives to greater than 35' and where you are not doing a square profile. Like ascending next to a wall or ramp etc..... Above 35' I run out of gas way before NDL even on multiple dives. Just my .03 cents

 

[divebutt]

Hi Jason,

I asume you are asking about the 4 reasons?

60 ft: Any dive below 60ft would be rounded to 70 ft, which would give you a NDL of aroud, off the top of my head, 35 min or so. Well a diver who is good on air runs the chance of running out of BT before running out of air. Thus, a computer is a good, constant reminder.

More than 2 dives: Assuming we're not talking about 30ft dives over 12 hours... Using a computer multiple dives gives more bottom time for each dive, and removes some human error from SI calculations.

Nitrox dive: same as a deep dive, but now you have oxygen toxicity to consider as well. Again, a computer is a safe and easy way to accuratley track the N2, and O2 levels in your body.

Multi day: Similar to more than 2 dives as above.

Just my 2 cents,

Cheers,

Divebutt

 

[caymaniac]

I have two computers, one is redundant. My dive partner has one computer plus gauges. We always check eachothers computers at least once when we are doing multiple dives. We have had so much more bottom time and isn't that one of the ideas of scuba is to stay longer at depth than if you just breath hold? I want to be down as long as possible as safe as possible. Yes I've had a computer malfunction, that's why I have more than one computer, this happened only once in the last ten years and I aborted the dive, and skipped a day so I could start over. With the tables once you go over 60 ft. your bottom time really gets wasted, I've had plenty of dives over 60ft. for over an hour with a computer. We've been on 2 liveaboards, it would be silly to go on a liveaboard without one (although I've seen it done).

 

[dexter98]

There are 3 main reasons:

1) Ease of use. Although the divetables are easy to use, a computer is even easier.

2) Spend more time underwater. Divetables use bathtube (worstcase) profile, while many real profiles (when carefully planned) are far from this profile. Many profiles will buy you more time in combination with a computer.

3) Timer and depth gauge in one device. This makes logging easy, usefull for navigation and time and it is also interesting to see your real profile on a computer screen.