Dive Computers & O/W

[Iguana Don]

Mario,

What you say is correct, but that is not the point in this case. Should new O/W students use a computer without mastering the tables. The question of are dive computers good or bad is not the issue.

We all use them, but I bet the majority, if not all of us on the board can use the tables if we need to.

Don

 

[turnerjd]

Guys,

We seem to have deviated from the origional topic, which was were computers suitable for o/w checkout dives, especially if this resulted in people being qualified, and not really having got to grips with the tables.

Having re-scanned all the posts, I am begining to wonder how many people *here* blindly rely on their computers (especially for non deco diving). There seems to be a general opinion that by default computers are safer than tables (again mainly limmiting to square profile, and multilevel non decompression dives). By the way computers work, you are default always closer to the safety curve, and hence less safe. By diving square profile and multi level table dives you always have large areas of the safe zone under the safety curve available, whereas the whole design of the computer is to let you remain along the edge of the safety curve.

Where computers come into their own in terms of dive time is obviously where you descend to depth, stay there for almost the NDL, and then slowly make your way up. computers monitor every few seconds, and as you ascend, you can stay pretty much on the safety curve if you want to, which is not possible by table diving. This results in NO margin for safety with the computer dive, whereas with the tables, by definition you stay under the safety curve, and have a margin of safety.

Computers for decompression diving are a different story, and in that case they are safer.

In the case of the OPEN WATER course students, with no experience, there is no advantage setting them on dives that will take them right along the safety curve. The advantages of computers come on MUCH more advanced dives, In the context of the open water divers, the only reason for getting them to dive with computers is a comercial one - the dive centre wants them dependant, so they feel they *have* to buy a computer.

Just my opinion of course,

Jon T

 

[Mario S Caner]

This reminds me of the type of replys I've been told about regarding the introduction of pressure guages, octopuses, buoyancy compensators, nitrox, the first computers etc etc etc. anyone else see the resemblance?

Anyway, the bottom line is that this practice is already being conducted with a flawless safety record by SDI (Scuba Diving International) http://www.tdisdi.com

We can discuss this until we are blue in the face. My point is that tables are discussed in the class, though they aren't required to be covered as in depth as say a PADI, NAUI or YMCA course, they are covered. The class momentum is then swithched to the safety and convenience in 'proper' computer use. And it works.

 

[Remora]

I don't think the line of thinking is the same as the reluctance to accept the BC or the computer, nitrox or otherwise. I believe the question is should we move away from teaching and mastering tables by the student at the O/W level.
To this I answer a resounding no.
I have seen far to often where automated sys have been put into use and have taken away the operators understanding of how the sys works. This can not be allowed to happen in diving as the student has to be fully aware of what happens and why. We should not be, nor allow the industry to become complacent with this. Understanding the "why" is the key and having a fail safe fall back ref is critical.

 

[Pam and Stella]

The computer vs. tables:

In the event of a power outage, one should know how to use a
candle!

I think Californians would readily agree!

 

[Rick Murchison]

Remora makes an interesting point - but that point actually supports what Gillium (and Mario and I) have been saying. Computers better calculate and represent the underlying theory behind dive tables *better than the tables themselves* - and a few minutes spent with a simulator in the classroom (Oceanic's simulation software, for example, allows you to look at a dive profile and what's happening on the computer side-by-side, and you can speed it up so a second represents a minute at a given depth, avoiding boredom) will give the student a clearer mental image of how the calculations are made, how the underlying theory of absorption and offgassing apply far better than hours and hours grinding through the tables.
Granted, there are some disadvantages to computers when considering missed dive time after a failure (24 hours), and there is an *apparent* safety margin in using the tables that isn't there when using the computer. The real world statistics, however, don't support a lot of "common knowledge." For example, the *lowest* incidence of DCS occurs among live-aboard divers, who are diving computers and making four to six dives a day, every day, for a week or more. That flies in the face of much "conventional wisdom," does it not?
Bottom line, as an instructor I see the computer only (no tables training or testing) option in OW training gaining steady support until, within the next three to five years, all major agencies will offer the "no tables" course for those who own computers, with the "computer mandatory" course firmly in place (already is with SDI) as the mainstream within the decade.
Rick

 

[Mario S Caner]

Rick,
Well said, I agree 100%. In fact I was quite surprised that another agency or two hasn't jumped on the bandwagon yet. With the next DEMA 18 months away, I'm predicting more changes in the way the mainstream agencies are doing things... as always most will disagree, deny, whine, cry and pound fists... I may be one of them too, who knows?

 

[Fishkiller]

I just purchased a Aeris 500AI and haved yet to complete my open water cert dives.(long story) I purchased the computer for two reasons the PADI wheel is tough to understand and teh DC will allow me to gather more information quicker and save it for later when I need to write it in my logbook.

 

[Remora]

Mario

I will probably argue, for all the reasons I have already mentioned. But I won't cry, whine or beat my fists on the ground. Let me put it this way... In my line of work I have seen the integration of computer sys to the point where a back up to the computer is another computer and so on. I have seen people that fully understood the principles and dynamics of their job so that if one of these sys went down they could manually complete the task. These people have left and have been replaced with "button pushers" they only know how to push the button and have no idea how to "troubleshoot" or in the event of a total blackout accomplish the task. If the sys gives false data they would not question it. I refuse to take this approach with my life or the people I train. Don't get me wrong I fully support computers and believe they have made diving safer, but I reitterate you must know the "why" A diver must have a means of defining a benchmark. You are right,there is most that will go down the garden path and jump on the proverbial bandwagon, but I refuse to put on the wool coat!

For Rick: I have read some of Mr Gilliam's articles and arguements, I can honestly say that in some (ie:his position on solo diving)of his articles he has forgotten the tgt audience of RD and has enticed a dangerous practice for the uninitiated.

I now have my hands firmly lashed to the whipping pole!

 

[Mario S Caner]

No need to brace for impact Remora. LOL! After all we're family around here. It's refreshing to see that not only are disagreements handled with utmost respect, but people care enough to voice it in the first place. Thanks all, to all of my new brothers and sisters.