Convince me to get a bottom timer...

[ucfdiver]

Imagine this.......you're doing a dive, your computer says 2min deco, buddy A has 6min deco, and buddy B's computer says 3min deco. Who's computer is right? Are any of them right?

Now, dive 2 for you, and dive 1 for your buddy using a computer. Your buddies computer isn't on a repetitive dive, and yours is......meaning you have no redundancy, and your buddy has no idea what your deco schedule is.

Now, you can say that you'll follow the tables and use the computer for backup, but often times the computers penalize you for deep stops, so you'll show deco when you're clear. Blow it off and surfacing results in being locked out for 24-48 hours.

 

[ae3753]

Imagine this.......you're doing a dive, your computer says 2min deco, buddy A has 6min deco, and buddy B's computer says 3min deco. Who's computer is right? Are any of them right?

Don't understand this point. What if I calculate my average depth as 50 feet, but my teammate says it's 60 feet? Decisions still have to be made.

 

[ucfdiver]

Don't understand this point. What if I calculate my average depth as 50 feet, but my teammate says it's 60 feet? Decisions still have to be made.

In your scenario I would assume the team makes these decisions at the first stop, and ascends on the same profile from there on out. This could easily be done by allowing the team member leading deco to do the average, hand signals (allowing each member to call avg depth or for more deco), or wet notes. With communication and a dive plan, I'd be surprised if it's an issue.

Am I over simplifying what you were trying to ask here?

 

[vshearer]

Computers are sooooo archaic.

 

[TSandM]

Oh, my goodness, what a flap.

The bottom DIR line is that you don't need a computer to tell you how much "no deco" time you have left, or how much deco to do if you are doing deco.

The fact is that it takes time to acquire the skills to monitor your depth and time and to understand the parameters within which depth averaging is valid. For most newer divers, a computer that will serve as backup information is valuable. Over time, and many dives of working at compiling and analyzing data underwater, you will get better and better at running a tally of your dive time and depth, and knowing when you need to head up, or when you need to do deco and how much.

Many, if not most of us, started with some type of computer. It is better to buy one that has the option of going into gauge mode, because that's where you'll end up. A resettable stopwatch, and resettable depth averaging, are nice features, which is why I own and used to dive an Aladin Tec2g.

If you are willing to dive tables, you can start with an inexpensive Uwatech bottom timer. But you can't push your bottom time from the beginning with one of those, and it won't give you any real-time feedback on whether you are doing your own sums properly.

 

[orange_diver]

Couple of questions for you:

1) "counting the knots as you go up".......what exactly do you do at 150'? Or are you carrying some huge spool...?

2) Why do you think that DIR divers do not have a back-up bottom timer?
3) What kind of GUE or UTD deco are you doing that asks for 180 seconds between 10-20'?

4) Also, you might want to revisit your knowledge of Ratio Deco............

1. My spool is 150' actually and it's not huge at all. deepseasupply. Plus, i wouldn't be starting deco at 150', i'm not doing those dives yet. more like first deep stop is at 110'.

2. My team is my redundancy. If some DIR divers wanna carry a backup BT, I could care less. I'm not the DIR police. Just saying you don't NEED one and pointing out some alternatives as to why.

3. That is not the deco schedule that I use, i was merely saying for a NON-ratio deco diver doing a NDL dive that a 3 min safety stop should at the least be made. The OP is not using ratio deco.

4. Why would you say something like this? What post have i made that suggests my knowledge of ratio deco is faulty? I've done abt 100 dives using RD so far and not a bend in sight.

Now here's a question for you: in MY scenario, the only way i would need to even bust out a knotted spool is if i had TWO failures, which we don't plan for. So, now i have a scenario for you: your TWO bottom timers both crap out. those are YOUR 2 failures. what do you do now? carry a 3rd BT?

 

[Gombessa]

Computers are sooooo archaic.

They're archaic because of all the logarithms.

 

[ae3753]

In your scenario I would assume the team makes these decisions... Am I over simplifying what you were trying to ask here?

Not at all. In my scenario with depth average and your scenario about computers with different decos obligations, decisions still have to be made. That is all.

Oh, my goodness, what a flap.

Hehehe.

Though I know a few people who would disagree with using a computer as a back-up, I too found this valuable in the process of becoming more comfortable with my depth averaging abilities and MDL dives.

 

[ucfdiver]

Not at all. In my scenario with depth average and your scenario about computers with different decos obligations, decisions still have to be made. That is all.

True, but the team makes the decision vs a computer making it, plus you can't get 3 computers to "agree" on a deco schedule at the first stop, and once again if you violate them by using buddy A's computer, you've bent the rest, and they'll lock out. During a failure or emergency, the team could elevate to a more aggressive deco schedule as well, I don't think any computer on the market can do that.

Please understand, I'm not criticizing anyone for using a computer, I'm just sharing the cons that made me decide to switch.

 

[Rick Inman]

Over time, and many dives of working at compiling and analyzing data underwater, you will get better and better at running a tally of your dive time and depth, and knowing when you need to head up, or when you need to do deco and how much.

I think this is true only when you turn off the computer and turn on the brain. Otherwise, you just get better and better at depending on the computer.

It's hard to "kinda" use your computer. There came a day when I just switched my computer to gauge mode and that was it - computer data gone. Now I really had to rely on my own brain, and at first it was a bit unsettling. But pretty soon I realized that there was more data in my head that I could access than I had thought. I started doing the 1 min moves on NDL dives and came out feeling better than when I did that 3 min, 15' SS my computer made me do (it was extortion, really. If I didn't do exactly what the computer said, it would punish me, and wouldn't let me dive again for a while).

After some non-computer dives under my belt, there was a day when I realized how much more free my diving felt - less controlled by the gadgets and more controlled by my own abilities - not that it's difficult to add two numbers to get 120 (or 80% of that). In fact, all the noise on the internet made it sound much more difficult than it really was to apply.

The computer doesn't know how old I am, how cold I am, how much I exert myself before, during or after a dive, how hydrated I am, how much sleep I've had, or any of that stuff about my buddy. I am different than every other diver, and every dive is different, but the computer just spits out the data the same every dive. And I actually used to trust that! I trusted my computer until the day I spent in the chamber with type 2 DCS, and my computer said I was clear. Granted, the hit was my fault. But I realized that the computer could not know anything about me and what I had done.

My bottom line is that I dive for fun, and for me it is a lot more fun and safe using the superior computer, the one always with me, the one that has all the data right at hand without even looking at it.

People should learn to dive without the computer, try it for a hundred dives, and then say which they like better. Most of the people who argue for letting the computer tell them how to dive have not the experience to compare and comment on the benefits of non-computer lead dives.