Diving without computers

[Bubblesong]

What's your friend's reservation about using a computer? And I assume he/she would have another means of tracking time and depth?

r.

My hubby is saying he never needed one in the past, but now that we are going to be empty nesters, I would like to do more diving and more types of diving. The improved bottom time can be used for better photography opportunities and that is going to be a key for planning next trip.

 

[boat sju]

Hmmm. I *have* heard this before, although I have never heard why some people are convinced of this. Safer than tables for open water, recreational diving? Not the way *I* was taught to dive tables (for the type of diving I do), I don't believe. Any idea why some people believe that diving a PDC for open water, rec diving makes diving "safer" than diving tables?

Safe Diving,

rx7diver

Safer because the computer shows you the advantage of a multilevel dive for off-gassing. What's safer, a reef dive to 100 ft for 20 minutes and then making a beeline to the surface because you're following your tables, or milking the 100 ft max dive to over an hour by hanging out at 25 ft by utilizing your computer properly?

boat

 

[Bubblesong]

I can do both: plan dives initially with tables, and keep an eye on computer model of how dive actually went.
One thing about dive computers is that if they Fail, as I have heard, I really want a written record of what my dives were, so I have somewhere to calculate next dive.

 

[Centrals]

There was a time when I have to rely "The Wheel" to plan multi-levels dives. Eventually I bought a computer which made the planning so much easier and quicker. I believe PADI no longer teaches "The Wheel" any more which is a pity because it is a pretty good alternative to Table. And I am pretty sure if you ask for a "Wheel" most operators won't be able to provide one.

 

[rx7diver]

Safer because the computer shows you the advantage of a multilevel dive for off-gassing. What's safer, a reef dive to 100 ft for 20 minutes and then making a beeline to the surface because you're following your tables, or milking the 100 ft max dive to over an hour by hanging out at 25 ft by utilizing your computer properly?

boat

boat sju,

When I was taught to dive using tables, "making a beeline to the surface" was never discussed. Using your example, the *longest* 100 fsw non-repetitive dive we would make would have us back to the surface at the 25 [sic] min NDL time. That is, we would leave for the surface at an ascent rate of 60 [sic] fpm so that we would be back at the surface at the 25 min NDL.

When I learned in 1986, *optional* safety stops were just being introduced. So, it was suggested that a diver could stop his/her ascent at 10 fsw and linger there for several minutes, gas and conditions permitting, before continuing to the surface.

The reality for our southwest MO and northwest OK freshwater lake/quarry shore diving is, we would descend directly to 100 fsw, and then gradually wend ourselves up to the surface, following the underwater contours.

We never gave ourselves "credit" for NOT spending our entire BT at the TOD of 100 fsw. And if the dive was planned for 100 fsw, then even if we descended to a maximum depth of only 85 fsw, the dive was treated as a 100 fsw dive.

Surface interval began when diver had exited the water (versus when diver had arrived at the surface). And diver began *dressing* for his repetitive dive when his surface interval had expired (versus began *diving* when his surface interval had expired).

This is how I still conduct my open water rec dives—except, being older now (almost 62 years old versus 32 when I learned), I now would use a 110 fsw schedule for a 100 fsw dive, for additional conservatism, and I now use a 30 fpm ascent rate. This is what I am teaching my daughters.

So, please explain again how diving a computer to maximize dive time (to maximize TTS) is safer than conducting the dive using tables as I have just described.

Safe Diving,

rx7diver

 

[Marie13]

So how many divers have been diving the old way, before computers, and still prefer it that way? I am sure everyone is planning their dive and diving their plans, but even with that as a baseline, if you only dive several easygoing vacations per year, is it worth the effort of trying to press those tiny buttons? Asking for a friend...

Having to do the math for tables rather than dealing with a computer? Really?! There's no pressing buttons unless you look at dive log after the fact or dive nixtrox, etc.

Let's just say I hate math and love my computer (and backup).

 

[2airishuman]

A lot depends upon where you will dive. If you are diving less than 30 feet with no possibility of going deeper, then you don't need a computer, a depth gauge, or a timer.

Which describes freshwater diving in many places. Around here, on most dives, there's nothing to see below 20', and not much reason to go there.

You should know how the computer is guiding you should you exceed your NDLs. That is an argument for owning your own.

A problem with DCs is that there is generally no way to simulate a dive, so aside from reading the instructions, there's no way to anticipate what the DC will do. My first 20 or so dives were shallow enough that my DC didn't ask for a safety stop. I was in the habit of doing them anyway, but was a little surprised by what the display did the first time I went deeper. I've never seen its deco display, which differs in important ways from the safety stop display, but at least I've read about it. A rented DC? I'd have no idea.

I honestly don't understand why one would pay money to buy a dive watch and a bottom timer and not a dive computer when a dive computer will cost the same if not less and still provide a lot more information that will make diving safer and much more enjoyable.

Leisure Pro has some very nice analog wrist-mount depth gauges for under $100 (new), and you can get any of several watches suitable for diving for around the same price. There's less maintenance and longer life than with DCs.

Any idea why some people believe that diving a PDC for open water, rec diving makes diving "safer" than diving tables?

Because most divers can't use tables as reliably and accurately as they can a computer. Some (many? most?) can't use them at all.

I find tables trivially easy to use. I imagine that most people who post regularly on scubaboard also find them trivially easy to use. But that is not representative of divers on the whole.

 

[BRT]

I can do both: plan dives initially with tables, and keep an eye on computer model of how dive actually went.
One thing about dive computers is that if they Fail, as I have heard, I really want a written record of what my dives were, so I have somewhere to calculate next dive.

Problem is that any planning you do with tables becomes meaningless if you are multi-level diving

 

[Bubblesong]

True BRT but We have always used tables, so we are probably going to keep using them for planning dives, initially, until I can convince the hubby to shell out for his own computer. So far only my daughter and I have them and his profile can't count on being the same as ours. So far increased safety, more bottom time and safety stop warnings are some incentives for him to consider.

 

[Goingforsound]

In 2017, first equipment you buy when vacation diving is mask, fins and computer.

It is important to understand our own computer. First step is to fully understand the manual. Rental is out of question. Unless you are learning a specific computer and its avail to you all week etc.

Provides the ndl, deco requirement, ascent and descent rates, logs, safety stop timer, easier to check than to reach for a depth gage. The first step in controling your diving and your safety is to have access to easy, direct info.

I saw some people blindly following the DM in Cozumel. With no computer or timer/watch. Apparently they were not checking their depth gage either because they were amazed when they asked me how deep we went and i answered 110ft. They were vacation diver with their OW only.