Is a computer actually necessary?

[MikeFerrara]

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

Why would anyone dive without one these days?

Because I don't need one.

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

Nonsense.

 

[Lucy's Diver]

If you're diving a typical recreational AL80 tropical moderate to (non tech) depths just get a computer. Your profile will be all over the place in terms of depth and you'll get more bottom time. You can spend the dive looking at the computer every once in awhile instead of recording depths and making recalculations.
Planning your dive to the degree necessary to use multi-level calculations is not realistic for most of the diving public. Most recreational, AL80, warm water diving is multi level and not that amenable to planning. For example, if your plan call for X time at Y depth and some rare sea creature is ten feet lower, are you really going to stick to the plan? You have to with a set of tables, or do on the fly recalculations.

You can do tables for the above sort of diving, but everyone else with computers will be getting more out of their dives.

Now, if you're strapping on twin steel 120s and slinging a pair of steel 40s with a total of three different gas mixes for accelerated deco, now it makes sense to use tables (or more appropriately, I think, use a multigas computer backed up with a software generated deco profile).

Or if you're breathing surface supply air with six guys on the surface supporting you, including a dive supervisor with two stopwatches around his neck to track your bottom time, tables are the only way to go.

 

[MikeFerrara]

If you're diving a typical recreational AL80 tropical moderate to (non tech) depths just get a computer. Your profile will be all over the place in terms of depth and you'll get more bottom time.

Your profile will only be all over the place if that's the kind of dive you want to do but I can still get all the bottom time I want without a computer.

Most recreational, AL80, warm water diving is multi level and not that amenable to planning. For example, if your plan call for X time at Y depth and some rare sea creature is ten feet lower, are you really going to stick to the plan?

No big deal even without a computer.

You can do tables for the above sort of diving, but everyone else with computers will be getting more out of their dives.

I get as much or more out of my diving as I did when I used dive computers. I wouldn't have stopped using them if I thought I was giving up anything.

 

[Theunis]

I've been diving for many years without a computer. I've bought one recently and did 8 great dives with it and will never dive without it in future!!

The reason for me purchasing a computer is the fact that I was getting frustrated depending on the diving group regarding deco times, water temperatures, etc. At the Natal South Coast, South Africa on the Protea Banks for instance, the reefs are between 100 and 130 feet deep. Profiles can be all over the place depending on say shark activity, etc. I 'd rather be watching my back than doing a deco recalculation. My computer is doing the job for me!!

Now I have all the information on my wrist and it also warns me if I "step out of line", or let's say "dive out of line"!!

 

[porsc]

nm please see below, as i mistakenly double posted. thanks.

 

[24940]

Until you understand and have used the concepts Mike is referring to for a time, your opinion lacks credibility.

 

[porsc]

mikeferrara, i don't know what your dive experience is, but your technique doesn't sound very realistic for most divers. no offense intended. in fact, it blows my mind that we are even having this discussion in this day and age of diving. and i can tell you, that it is hard for me to believe that you are getting as much out of your dive as i am, when you are sitting down there and doing calculations, instead of enjoying all of the marine life.
the big problem with the original question is that one word used, "necessary".
is a washer and a dryer necessary? are forks and spoons necessary? is a car necessary? is it necessary to have a roof over your head every night? are shoes necessary? none of those things are necessary, but they sure make life a lot easier and nicer for us to go about our daily lives. the same is true with using a dive computer.
why would anyone want to carry tables with them, and re-plan their dives as they go? because i can tell you, as one of the more experienced persons on this board, people rarely if ever dive their exact plans. once you hit the water, things change. the marine life rarely cooperates with our dive plan. they go to different area's and depths. this is one of the biggest reasons to have a good computer. it recalculates your profile, in real time, as you go, which can help keep you from ending up diving at the limits. also, how many times have people gotten caught up in looking at something really cool, and made a mistake in their plan, because they weren't paying attention. this is actually very common, and without a computer it is very likely that you won't even realize it, therefore not take steps to correct it. the computer keeps you in line, and even advises you on different things, like deep stops.
unlike a lot of people on this board, i dive every single day. and almost all of those days i am taking people diving with me. so having a computer to make sure that things are done properly, is just sound thinking. also, with human error being what it is, how easy is it for the common person to make a mistake while planning their dive with the rdp? the chances of that mistake goes up considerably when re-planning underwater. when i'm diving, i want to dive, not do calculations, where i am taking my attention off of the actual dive, or the marine life around me. i wonder if mike has ever heard of perceptual narrowing? if you are down there trying to make calculations, there is also the chance of getting into trouble because you are concentrating on the calculations, and not what is happening on the dive. besides, having to do that is so 70's and 80's. yaba daba dooooo!!!!!! fred flintstone!!!!!!
get with the program people, this is the 21st century! while i in no way subscribe to the mentality of the shop owner who treated the original poster poorly, i do agree with what she was trying to say, even though she went about it completely wrong. that's NOT to say that if you don't use a computer you are stupid, but unless your doing 30 to 40 foot square profile dives, you aren't really being very smart, in my opinion.
i hope no one is offended by any of my statements, they weren't meant to offend. but i have been at this since 1980, and i am now in samoa, which is my 35th country living and/or working in this industry. if you are going to dive two or three times a year on vacation, then it probably isn't going to be cost effective to buy a computer. but if you are going to dive regularly, i would advise buying a decent computer, and will not insult you if you don't.
as far as mike having a sure proof way of doing all of this without a computer, that is good for him, and i don't doubt him. but this discussion is for many people who just started diving (ie the original poster), or people who don't have that skill. while making my argument, i am not considering rather mike can or can't actually do what he says he can. he probably can. i'm trying to think about all of the people who are reading this, that can't do what mike does, or who wouldn't want to bother, since a good computer can do all of it for you, quickly and thoroughly. so i am just trying to think about the common diver, not just one person who cares to do it the old way. i hope this helps.

 

[Lucy's Diver]

Until you understand and have used the concepts Mike is referring to for a time, your opinion lacks credibility.

I think I understand. I understand that my dive supe, and not me, is calculating my bottom time, depths, and deco profile (if any) for a reason on a work dive. I have other stuff to do down there.
Similarly, I have other stuff to do on a common warm water AL80 recreational dive. I don't want "dive my plan" to mean rigidly obeying a pre-planned depth plan. Plans seldom survive first contact with the enemy and all. I want the freedom during the course of a no D recreational dive to focus on enjoying the dive, and that means multi-leveling all over the place to see what there is to see at that place and time. I guess I'm not smart enough to do that and recalculate the deco stuff on the fly.
Over the course of many, many, recreational AL80 dives I've seen one guy not use a computer. He must use and understand those concepts.
Frankly, I understand how to make fire with sticks also, but I like to use a match.

 

[24940]

I guess I'm not smart enough to do that and recalculate the deco stuff on the fly.

It's not about smart. On the rec level, it's pretty basic. Min deco, rock bottom, depth averaging and the rule of 120 are all very easy concepts to grasp and employ.

 

[charlesml3]

I'm with porsc, here. I'm sure a computer isn't absolutely necessary, but I'm sure not diving without one. There's no reason NOT to. I dove Mary's Place today in Roatan and it was so nice not to have to worry about my max depth and calculate that as depth/time. Just let the computer keep up with those data points. It can do it better and faster than any diver can. The computer is a tool. Use it to your advantage.

Dive computers allow the vast majority of recreational divers to get more bottom time safely. And bottom time it what it's all about.

-Charles