Is a computer actually necessary?
- Thread starter Kimsey0
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Computers and tables are 2 means of implementing the same science.
Just as you can have different tables you have different computers with different algorthyms.
BOTH however both do identical things. Tables are always a "worst case scenario" expecting a square dive profile whereas computers will be more accurate and adapted to the current dive profile
Remember though the science that both these are based on is just a statistical approximation of how likely it is not to get bent. A computer will more accurately follow the statistical table however that doesnt mean much when the core data isnt perfect in the first place.
Is a computer essential ? Most definately not, you can use tables
Are tables essential ? Most definately not, you can use a computer.
Both have exactly the same function.
If most of your dives are pure square profile then a computer wont give you more than tables. If however you do a lot of multilevel diving, often not knowing the exact profile until on the dive a computer can buy you more bottom time without increasing your risk.
I started diving without a computer living quite happily on tables but since bought a computer and finding it very useful, not only for dive logging but for increasing my bottom time as i very rarely end up on a square profile dive. I keep a spare set of level 1 tables in my BC pocket just in case the incredibly unlikely happens and my computer and buddies both computers die. Inevitably it'll mean more possibly unneccesary deco stops but it will get you out as safely as possible.
I find the computer gives me far more flexibility in my diving and the advantage of having an ascent rate displayed ans so on is nice to have - much easier than looking at my watch to try to gauge a rate.
Just as you can have different tables you have different computers with different algorthyms.
BOTH however both do identical things. Tables are always a "worst case scenario" expecting a square dive profile whereas computers will be more accurate and adapted to the current dive profile
Remember though the science that both these are based on is just a statistical approximation of how likely it is not to get bent. A computer will more accurately follow the statistical table however that doesnt mean much when the core data isnt perfect in the first place.
Is a computer essential ? Most definately not, you can use tables
Are tables essential ? Most definately not, you can use a computer.
Both have exactly the same function.
If most of your dives are pure square profile then a computer wont give you more than tables. If however you do a lot of multilevel diving, often not knowing the exact profile until on the dive a computer can buy you more bottom time without increasing your risk.
I started diving without a computer living quite happily on tables but since bought a computer and finding it very useful, not only for dive logging but for increasing my bottom time as i very rarely end up on a square profile dive. I keep a spare set of level 1 tables in my BC pocket just in case the incredibly unlikely happens and my computer and buddies both computers die. Inevitably it'll mean more possibly unneccesary deco stops but it will get you out as safely as possible.
I find the computer gives me far more flexibility in my diving and the advantage of having an ascent rate displayed ans so on is nice to have - much easier than looking at my watch to try to gauge a rate.
I personally find my computers very useful tools for a variety of reasons; however it is important to me to plan my dives with tables and I always dive that plan. I happen to plan them as multi-level dives to get the most bottom time for my particular dive. (Another rule is to plan a contingency for a just in case incident. i.e. Just in case you end up deeper than your plan)
If you are not planning your dives and diving that plan (with tables), you can very easily overstay the table's ndl while staying comfortably within your computer's limits. It is also wise to take along a timing device and another guage to measure depth as well as a slate to record the multi-level data. That said, if the computer fails and you are diving your plan you are still able to continue the dive and continue diving the rest of the day. Otherwise, you should immediately ending that dive and sit out the rest of the day's dives. Your dive vacation can become that much more expensive if this happens.
Too often I see divers in Cozumel on the fast boats to the deep walls doing "trust me dives". Many never pull out a table or plan their dives. Many don't even have a timing device. Having a computer helps them to avoid the planning process and still check themselves during the dive. Although I don't advocate diving without a plan, using a computer is way better than diving blindly where the divemaster takes them. The DM physically can't control nor watch every diver's profile.
Go ahead and flame me, if you like. Why not get the best tools you can afford. And don't forget to shop around.
If you are not planning your dives and diving that plan (with tables), you can very easily overstay the table's ndl while staying comfortably within your computer's limits. It is also wise to take along a timing device and another guage to measure depth as well as a slate to record the multi-level data. That said, if the computer fails and you are diving your plan you are still able to continue the dive and continue diving the rest of the day. Otherwise, you should immediately ending that dive and sit out the rest of the day's dives. Your dive vacation can become that much more expensive if this happens.
Too often I see divers in Cozumel on the fast boats to the deep walls doing "trust me dives". Many never pull out a table or plan their dives. Many don't even have a timing device. Having a computer helps them to avoid the planning process and still check themselves during the dive. Although I don't advocate diving without a plan, using a computer is way better than diving blindly where the divemaster takes them. The DM physically can't control nor watch every diver's profile.
Go ahead and flame me, if you like. Why not get the best tools you can afford. And don't forget to shop around.
IndigoBlue
Contributor
If you never dive deeper than 50 ft, then you may never need a computer. Charts work fine for such shallow work.
If you start diving deeper than 50 ft, then a computer is really useful.
My computer was my last gear purchase. There is no rush, in my opinion, to buy a computer.
If you start diving deeper than 50 ft, then a computer is really useful.
My computer was my last gear purchase. There is no rush, in my opinion, to buy a computer.
ScoobyPat
Guest
*shiver* Although I am a nitrogen junkie, I would never dive without a timing device and a plan. Sounds to me like an accident waiting to happen if they go deeper than 30ft. I always lose track of time while diving.
:shiver:
Actually if you get use to checking your gas supply and your depth every 5 minutes you might find that you activate your built in timer and develop not only a sense of timing but automatic tracking of your gas consumption as well.
I can tell time with my SPG.
ScoobyPat
Guest
my built-in timer is broken. some people wake up every morning one minute before their alarm goes off. i traditionally miss that by about an hour. hehe 
brush your tooth and get to bed!
ScottyK
Contributor
I got this tip from UP back in the spring, and worked on it all summer. It's well worth trying.
I already had a good handle on my bottom time and gas supply, but felt I was relying on the computer too much, and wanted to get back to memorizing the tables.
As I just stated, I was doing a good job of keeping track of things already. However, after formalizing it to a regular time interval and practicing on every dive, it's becoming so automatic I barely notice I'm doing it.
Another benefit to breaking up your air usage into snapshots is you'll start to realize that there are things you do that cause you to use more air, and you can work on changing those behaviors. I noticed that I hoovered up a lot of air in the first five minutes of my dive. I realized it was the exitement I felt at getting in the water. I now do a couple of minutes of "zen time" at the surface, which took care of the problem.
I also went from guessing right within 100 to 200lbs when I check my air, to being almost spot on every time. It's the same with bottom time as well. It's a good feeling to know that, barring catastrophic failure, I'll never be in an OOA situation.
Scott
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