Dive Tables

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I have seen watches go slow and I have seen watches stop.
Yes I am in the Computer fraction for recreational diving and I am not even convinced planning a tecnical dive with tables is superior to using an electronic tool like Multideco

I make my living testing hi-tech components and assemblies like those that make up the PDC. I've seen software glitches, conflicts and just bad software that worked during testing but not in the field. That means when we are using it. I've seen hardware failures to write home about and the imbedded software of multiple components fighting for control stop working.

I'd rather guess at my time and depth than to rely on this technology at this stage of it's development w/o backup. It is also the biggest issue I see with reliable RBs the technology is not up to it 100% of the time. Never had a watch stop on me during a dive. I did however have a battery in my PDC die during a dive, my watch and depth gage took over and saved the day. I check every dive on tables 1st before I even turn the PDC on.
 
Yeah! It boils down to type of diving. If you are doing a typical 2 tank boat dive in the U.S./Canada it may go like this: First dive 80' for 25 minutes. Hour+ S.I., travel to 2nd site. 2nd dive 60' for 35 mins. Crew is happy you have 500 PSI reserve each time. Assuming even a square profile, there is no major advantage having a computer. If your dive is more multi level-like, with longer bottom times obviously the computer makes a big difference. If you're diving 20-30', who cares?
And to add to that, If I'm diving lets say an offshore pinnacle with the potential to go really deep and I spend most of the dive at 60 feet. Then something catches my eye at 120 feet so I drop down to take a look. After 1 minute I leave and go back up to 60 feet and keep cruising. On tables I'm not going to count this dive as a dive to 120 feet the whole time like they want me to. That might be great for somebody that can't depth average and I can see they set the rules with tables to use them with square profiles and most of that was to idiot proof them and reduce liability. But I'm not going to count 120' for the whole dive because I wasn't down there the whole dive.
I will add maybe 10 or 20 feet to my 60 and average the dive at 80' and set the time accordingly. If I decide to do the rule of 120 that will give me 40 minutes (first dive). I also always do a few stops at 30 20 and 10 on any dive like that.

On beach dives to 40 or 50 feet with a gradual sloping bottom doing an out and back, I never use a computer. I'll run out of air way before I'm anywhere close to NLD. A computer is just one more thing to potentially lose or damage on a beach dive.

I just think this whole computer fanatasism is rediculous. People are so on a cloud these days and have forgotten how do to anything manual anymore.
Pretty soon there will be computerized BCD's that auto regulate inflating and dumping. Then instructors will get to only teach computerized BCD diving and won't teach how to manually inflate and dump your BC. for perfect buoyancy.
I swear!
 
Eric

I suspect you've got the scuba diving experience, plus time in on forum discussions, to have some sense of what rules to 'bend' (without getting bent yourself), what rules to break and what limits not to push, and all the while are capable of making informed decisions about risk as you do so.

Most fairly new divers are none of those things.

Divers are taught to more standardized practices these days than long ago, as these practices do, when followed, produce a good track record of safety.

The kind of 'make your own interpretation' thing you describe may make sense to you. But remember that huge thread about the non-cave certified guy who took his 15 year old son cave diving at Eagles Nest, and they both died? Sure, what you're doing is not the same thing, or I would think anywhere near as risky, but making personal risk choices about the 'shades of grey' is something a seasoned diver might do (and at least understand the chances he's taking).

For a newcomer to the hobby, I suggest a computer. Tables if you must.

Richard.
 
Eric

I suspect you've got the scuba diving experience, plus time in on forum discussions, to have some sense of what rules to 'bend' (without getting bent yourself), what rules to break and what limits not to push, and all the while are capable of making informed decisions about risk as you do so.

Most fairly new divers are none of those things.

Divers are taught to more standardized practices these days than long ago, as these practices do, when followed, produce a good track record of safety.

The kind of 'make your own interpretation' thing you describe may make sense to you. But remember that huge thread about the non-cave certified guy who took his 15 year old son cave diving at Eagles Nest, and they both died? Sure, what you're doing is not the same thing, or I would think anywhere near as risky, but making personal risk choices about the 'shades of grey' is something a seasoned diver might do (and at least understand the chances he's taking).

For a newcomer to the hobby, I suggest a computer. Tables if you must.

Richard.
You're right about the newbies, they need to follow the prescribed rules and stick with what they are taught.
*Note to newbies: Don't do what I do, do what your instructor tells you and follow the current teachings of SCUBA protocols whatever the training may be.


My issue is a little bigger than just diving when it comes to computeruization. I'm seeing examples in many walks of life that computerization is making our brains atrophy because we don't need to think anymore.
I can site many examples like GPS units in cars, the whole sign and graphic arts industry, calculators for simple arithmatic, and the list goes on.
I've seen a lot of creativity suffer because of reliance on computers.
For diving, tables are one of the simplest devices out there. I remember the first time I got a computer, it was a Suunto Vyper wrist mount. I already new tables before I got it so it was more of a cool new toy that was all the rage at the time. I soon found myself just looking at the computer and getting tunnel visioned into mindlessly following it. I started to lose my natural time and depth situational awareness where you look and sense the big picture of how long you've been down and what depths you've been to. It happens to the best of us, to get myopic staring at the computer screen and becoming a mindless follower.
I remember once I went up to Tahoe (6200' elevation) and did some diving. I set my computer for altitude and also set it for conservative since the next morning we had to rise to 8300' going over the pass to go home.
The following weekend my buddy and I go out to the ocean and I forgot to reset the computer to our current dive.
After a very short time the computer freaked out and sent me up to 15'. My buddy was no where near his NDL on his computer. So if I would have been paying attention to depth and time independently of the computer I would have known something was wrong. And yes I could have looked at time on the computer and probably realized something wasn't right, but it never works that way. People inherently will focus on the time remaining and that will be the leading factor of the dive, it's just the way we are - following the path of least resistance, or the easiest way.
So then I hooked up with a bunch of divers that didn't use computers and were able to calculate on the fly. I felt like a complete idiot because I didn't know how to do it and had to follow a computer. One day I was out kayak diving and lost my computer during a roll over. I didn't have the money to replace it, so I figured it would be a good time to learn from those other guys how to compute dives in my head following tables.
What a liberation! It was so easy.

I know computers are imbedded in every walk of life and are here to stay. All I'm saying is I think it's a great idea for people to know tables so if nothing else they know what the computer is based on. Even if tables are never used it's good to know them. The more people things people have knowledge of the better, it's good for our brains. Analog keeps our feet on the ground. Losing that and living up on a cloud scares me because I personally am a little uneasy about trusting my safety and life solely on an electronic device.
 
Thank you to everyone that has been so kind and informative in their responses to me. In doing research on computers and chatting with my local dive shop, it seems I am in the minority of the newly certified divers, having been trained on tables vs. computers. In fact, my LDS said "you obviously didn't train with us". Nope- I didn't. I was trained & certified in Jamaica, we used tables to log our dives and was just trying to refresh my memory so it would be second nature, so to speak, while I am in Belize on my dive trip. I would love to be independent and NOT have to rely on my DM for everything. I am a visual learner by nature and when I posted I was simply asking if anyone knew of reliable sources that cover tables for a refresher, simplifying my own searching. Thankfully, I was directed to a great video series and am so grateful for that!

Now for the irony of this entire thread- I will be diving with a computer! Turns out, the dive shop we are using sent this in response to my question regarding renting one from them- "As part of our commitment to the best diving practices, we provide all of our divers with personal dive computers while diving with us, free of charge. Renting a regulator from us, your regulator set up will come complete with an air-integrated dive computer, no worries there!"

Looks like I'm covered on both fronts- I'll dive with a computer, however will be comfortable with my tables as well!

Happy diving to you all!
 
I agree with the whole PAGE. New divers shouldn't get into any grey areas (I didn't my 1st or 2nd dive when I spent all of 3 mins. at 54', the rest at 20', calculated my tables and figured I'm done for...duh..). But you still have to know what you're doing to do multi level table dives--for me not worth the effort plus possibility of a math mistake. All the above posts point to use a computer (again, not if shore diving 30', just one more item that may flood, break, or at least that needs to be rinsed), know the tables anyway, and be logical.
 
And to add to that, If I'm diving lets say an offshore pinnacle with the potential to go really deep and I spend most of the dive at 60 feet. Then something catches my eye at 120 feet so I drop down to take a look. After 1 minute I leave and go back up to 60 feet and keep cruising. On tables I'm not going to count this dive as a dive to 120 feet the whole time like they want me to. That might be great for somebody that can't depth average and I can see they set the rules with tables to use them with square profiles and most of that was to idiot proof them and reduce liability. But I'm not going to count 120' for the whole dive because I wasn't down there the whole dive.
I will add maybe 10 or 20 feet to my 60 and average the dive at 80' and set the time accordingly. If I decide to do the rule of 120 that will give me 40 minutes (first dive). I also always do a few stops at 30 20 and 10 on any dive like that.

On beach dives to 40 or 50 feet with a gradual sloping bottom doing an out and back, I never use a computer. I'll run out of air way before I'm anywhere close to NLD. A computer is just one more thing to potentially lose or damage on a beach dive.

I just think this whole computer fanatasism is rediculous. People are so on a cloud these days and have forgotten how do to anything manual anymore.
Pretty soon there will be computerized BCD's that auto regulate inflating and dumping. Then instructors will get to only teach computerized BCD diving and won't teach how to manually inflate and dump your BC. for perfect buoyancy.
I swear!

Anything less than 5 mins is considered a "bounce" dive so the 1 min at 120 isn't counted at all when using tables. The auto BDC has been done already it was a Dacor Nautilus a hard shell back pack that held a tank and a 20#lead ingot. It had an inflator with a diaphragm that reacted to the ambient pressure and added air when the diver went deeper. The hard shell was flooded with water until the diver sunk. The unit would then take over and add air and expel water as the diver descended. It had a valves at the top and bottom that opened and closed to expel water or air. Manual control was always possible and the 20# lead ingot was manually released if need be. Pretty cool and too far ahead of its time to catch on. Check it out: http://www.scubaboard.com/forums/vi...8752-dacor-constant-volume-system-1980-a.html
 
Anything less than 5 mins is considered a "bounce" dive so the 1 min at 120 isn't counted at all when using tables. The auto BDC has been done already it was a Dacor Nautilus a hard shell back pack that held a tank and a 20#lead ingot. It had an inflator with a diaphragm that reacted to the ambient pressure and added air when the diver went deeper. The hard shell was flooded with water until the diver sunk. The unit would then take over and add air and expel water as the diver descended. It had a valves at the top and bottom that opened and closed to expel water or air. Manual control was always possible and the 20# lead ingot was manually released if need be. Pretty cool and too far ahead of its time to catch on. Check it out: http://www.scubaboard.com/forums/vi...8752-dacor-constant-volume-system-1980-a.html
I knew about the Dacor product from reading some of Sea Rat's post in the past.
What I was imagining was a BC unit that has a regular air bladder but would have a computer module that when you set the desired depth you want to dive at it does everything to automatically stay at the set depth by auto inflating and dumping via a sensor that is hooked up to an internal depth gauge. The inlet and exhaust would be powered by servos that would run off pneumatic pressure. I guess somewhere there would need to be power but in this day and age that wouldn't be hard to figure out.
The depth could be operated by a dial that you could turn as you are going along or it could also be operated by a sonar that keeps you at a pre-set depth from the bottom typography. So in other words incompetent divers that can't figure out how to get neutral to save their life could cruise along a coral reef and never have to worry about crashing the bottom. The computer operated BC won't let them.
This would be inline with everything else I see happening with the direction of diving.
They could even have fins that have hinges with little motors that flap them back and forth. Then a diver that doesn't know how to use fins properly could just keep their legs straight and the fins will automatically do all the work.
Of course there would have to be specialty classes for these things because you would have to have training and a card to prove your qualified.
 
I think one of the points that is confusing people is that you keep saying you want to use tables to log your dives since you weren't going to have computers.

The computer logs the dive. Tables are used to plan the dive before the dive, not log the dive during and after the dive.

Enjoy Belize. That's one of the places I want to go dive someday!
 
I think one of the points that is confusing people is that you keep saying you want to use tables to log your dives since you weren't going to have computers.

The computer logs the dive. Tables are used to plan the dive before the dive, not log the dive during and after the dive.

Enjoy Belize. That's one of the places I want to go dive someday!

Just semantics. On dives deep enough that I use my computer (over 40'), I use tables to plan the dive, to plan the 2nd dive after SI, and to log the dive in my book after the dive (assuming a square enough profile that I can actually figure pressure groups). I also use my computer all the time and don't use it to log the dive when done (haven't bothered to find out how to find where it logs the dive for me).
On shallower dives I use tables only for all this stuff.
Obviously I am well versed with the eRDPml as well as it was part of the DM course--haven't used it yet, though it's fun to play with.
 

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