Dive table vs computers

[HPT3]

I'm making some big purchases with this hobbie and all are necessary. The only purchase I'm unable to decide on is a computer. I've gone throught the ow class straight to the advanced and I hope to do alot of wreck diving off the NJ coast. Will a computer make a significant differance verses using the dive tables. I'm also taking a nitrox class. I know this will extend my time, but again, if I use a computer rather than the dive tables is it a significant amount of time.

 

[Don Burke]

HPT3 once bubbled... I'm making some big purchases with this hobbie and all are necessary. The only purchase I'm unable to decide on is a computer. I've gone throught the ow class straight to the advanced and I hope to do alot of wreck diving off the NJ coast. Will a computer make a significant differance verses using the dive tables. I'm also taking a nitrox class. I know this will extend my time, but again, if I use a computer rather than the dive tables is it a significant amount of time.

If you are changing levels down there, the computer gives you credit for time spent shallow so you get more no-stop time.

New divers often find themselves limited by their air consumption and a computer can't help you there. You may find yourself using air until you can make your gas last long enough to justify the extra money for nitrox.

The good news is that you can put off your computer decision for a few dives since you won't be getting the most out of it anyway. That will give you a chance to pick the brains of people you dive with.

 

[DA Aquamaster]

Computers make a lot of sense in multilevel diving and in high altitude diving but have fewer advantages at sea level or over a more or less level bottom.

If you plan for a max depth and time and then dive the plan with little or no deviation above the planned depth, a computer will offer you no real advantage over a table in terms of bottom time at medium depths. (However some computers are actually more liberal at deeper depths than the US Navy tables)

For a square dive profile, most computers will actually offer less bottom time than a table. However you also want to be very careful diving square profiles with your tables as when used in that fashion they offer little or no saftey or fudge factor. You either need to back off on the depth or bottom time to remain well within the NDL, or plan for the next deeper depth and time, or add some very conservative saftey stops (and you are far better off considering them to be deco stops, rather than saftey stops.)

Your best bet is to dive for awhile with your tables, get proficient with them and then see what your dive buddies are doing or using before you decide whether to purchase a computer or not.

 

[Karl_in_Calif]

Just because you plan to dive wrecks in the future, should not rule out a good dive computer purchase now. It just means you should think about a quality dive computer, with a gauge mode feature, so that you can use it in the future when you do dive wrecks.

If you get a Suunto Vyper dive computer, you can use it for all kinds of diving, and you will be glad you have it, because it records all the details of your dive, so that you can read it back afterwards in the PROFILE feature.

If you are diving to a wreck, you will probably stay at one given depth. So whether you use a bottom timer or a dive computer does not matter much.

But in the meantime, while you are diving NDL open water dives, a dive computer is quite nice, to keep track of your remaining NDL time. A nitrox dive computer is expecially nice, since you may be doing repetitive diving, and nitrox lends itself well to numerous repetitive dives.

If you are penitrating the wreck, or staying down longer than NDL, or going deeper, then you will have multiple gasses with you and will be deco diving. In that case your Suunto will still work well, however it will be in GAUGE mode, where there is no NDL model.

For tech diving, you would normally use some kind of depth/time gauge, and possibly some type of backup gauge (not all agencies require a backup gauge).

So a dive computer is a good investment. You just need to make sure you get a good one, rather than a cheap one.

 

[RICHinNC]

I like the compensating the pc will do for you.....
but i like most of all being able to accurately and more important quickly being able to check my ascent rate....and hover depth.

SPGs just arent quick enought to react for me where a pc you can watch your bobbing very well.

I would recommend a pc as soon as you can afford one. The nothing to do with life saving features like recording a series of dives for you is pretty handy too. I can dive now...do the paperwork later.

Key features for a pc to me are....
...the battery can be changed by me...not have to be sent off
...large readout numbers
...easy to understand layout
...wont break the dang bank.
...no transmitter involved
...good reputation
...backed by the company

so i went with a genesis resource.

 

[DA Aquamaster]

I agree with your ideas on key features a computer should have and selected aGenesis Wisdom. The break the bank thing is relative and a Wisdom is $350 or so cheaper than a similar Uwatec (plus the warranty service is arguably better and undisputably faster.)

I also agree to a limited extent on the computers usefulness in judging ascent rates and hover depths. But my preferenece, particularly for a new diver, would be to learn to use the natural visual cues availble including visual reference to the surface, and/or to suspended particles in the water, as well as the ascent rate of your own exhaust bubbles for judginf ascent rates.

For hovering you can also reference suspended particles in the water and once you are really in tune with your bouyancy, you can feel ascent and decent rates that even your computer won't detect. From this you will know if your rises and descents on inhaling and exhaling are averaging out properly.

Following the smallest exhaust bubble you can see will give a very good ascent rate of about 30 fpm. However you will have to keep selecting new bubbles as you ascend as the small bubbles expand on the way up and increase their ascent rate.

 

[RICHinNC]

that is so true DA....but i can not tell you how many times i have seen someone fixate on the bubbles and match their speed.

just came back from barbados....and i dove with several new and certified years ago....just back to diving people....

i never really knew how well i dived until i watched them....plus the dm on one dive said they werent worried about me...they had too many divers that didnt have a clue to watch...
gave me a little sense of accomplishment....ill take what i can get!!!

 

[ScubaRon]

Wreck-diving usually means spending most of your time at one depth, so a computer is not going to benefit you very much.

While you are undecided (or out of cash) you can also consider the PADI Wheel. It enables you to do multi-level diving (I believe up to 3 levels...it has been a while since I used one).

It takes a little studying to understand it, but it does the job nicely. I think they're about $45 new.
ScubaRon

 

[MechDiver]

RICHinNC once bubbled...

but i like most of all being able to accurately and more important quickly being able to check my ascent rate....and hover depth.

SPGs just arent quick enought to react for me where a pc you can watch your bobbing very well.

I can do this with a bottom timer.

What does an SPG have to do with dive computers

MD

 

[MechDiver]

ScubaRon once bubbled...

While you are undecided (or out of cash) you can also consider the PADI Wheel. It enables you to do multi-level diving (I believe up to 3 levels...it has been a while since I used one).

Is Padi still pushing/making that thing? I've got one for $20, you pay the shipping

MD