How to plan second dive of the day using a computer

[Ste Wart]

It should be.

Getting apprehensive and rushing an ascent just because your DC says you have strayed into deco is the problem, IMHO.

There's a great bugs bunny cartoon, where Elmer Fudd chases Bugs over a cliff; they both hang in mid-air until Bugs hands Elmer a book titled The Laws of Gravity. Elmer reads it, and then promptly plummets. Bugs then says "Ignorance is bliss"

What am I saying? KISS is what I'm saying. Divers know what they need to know at each level. We don't need to have PhD's to be OW divers.

 

[lowviz]

You have convinced me that you are holding to your position.

I have another way of looking at the same issue, "accidental light deco" and a recovery plan are not too much to understand for the OW diver. Avoiding panic is the main value of such.

 

[Ste Wart]

You have convinced me that you are holding to your position.

I could say the same.

I have another way of looking at the same issue, "accidental light deco" and a recovery plan are not too much to understand for the OW diver. Avoiding panic is the main value of such.

The OW diver already has the tools, the extended/mandatory safety stop. The OW diver knows what to do. Recovery plan? Hardly KISS, methinks you take diving far to seriously.

 

[DevonDiver]

As I see it the deco mode is not something to be understood by the casual diver.

Then why do the agencies see fit to teach emergency deco procedures when teaching with tables? Why the disparity?

Which is why we teach basics for exceeding NDL's i.e extended safety stops.

Which is the point I am raising. Now that courses are more focused upon computer-diving, is that being taught? (sufficiently).

There is little need for more knowledge than this for the casual diver.

You're absolutely right... but.... when the 'casual' diver gets into deco, they're confronted with a very different display... different concepts. There's no option or information for 'safety stops'. They see the words "ceiling" and "ascent time".. for the first time. There's arrows pointing upwards, downwards and sideways. Stuff starts flashing and beeping.

I once saw a diver rush out of the water and back onto the boat "because their computer had failed". Upon discussion... it'd gone into deco. They didn't understand it. That wasn't a casual diver.... that was a Divemaster (trainee). Ooops... break out the O2...

I've seen 5 or 6 similar admissions here on Scubaboard in the last few months. "Why is my computer locked out and won't go into dive mode?!?"

All this information is given on the computer screen, as the diver approaches safety stop depth the penalty time is already clear for the diver

I don't think it is clear for the diver. It should be, but it isn't.

Personally, I'd prefer it if 'recreational' computers put a 'cap' on deco... giving no option but to surface. To help safe surfacing, they should keep a recognisable display interface and use consistent terminology and visual guidance. Something like "Ascend Now" and alarms continuously.... then on reaching deco depth it shows "Stop Depth" with countdown. It stops beeping when you get to 5m and gives you the time to wait (as per safety stop info). It alarms and flashes whenever you ascend above, or drop below, that depth.

As to what understanding you need beyond 'doing a longer safety stop' I don't know.

This....

Judging from my own experiences, a large proportion of novice divers seeing that would assume that the 'Asc Time' was some continuation of their NDL limit. Scary, but not unrealistic.

 

[rhwestfall]

look at the current NAUI tables.....

150 min @ 40' = 5 min @ 15' (130 min@40 limit for no-deco)
100 min @ 50' = 5 min @ 15' (80 min@50 limit for no-deco)
80 min @ 60' = 7 min @ 15', 60 min = 5 min @ 15' (55 min @60 limit for no-deco)
70 min @ 70' = 14 min @ 15', 60 min = 8 min @ 15",50 min = 5 min @ 15' (45 min@70 limit for no-deco)
etc....

the info is there for the recreational diver - its on the tables... and even an end PG......

I can only hope it is covered..... (it was for me, but that was 23 years ago through a not-for-profit [YMCA])

 

[Ste Wart]

You're absolutely right... but.... when the 'casual' diver gets into deco, they're confronted with a very different display... different concepts. There's no option or information for 'safety stops'. They see the words "ceiling" and "ascent time".. for the first time. There's arrows pointing upwards, downwards and sideways. Stuff starts flashing and beeping.

I can't look at that with anything but instructor eyes though. If I see ceiling my mind says limit. Will the average diver figure this out? I would have to say yes, we are all aware that a ceiling is limit.

Personally, I'd prefer it if 'recreational' computers put a 'cap' on deco... giving no option but to surface. To help safe surfacing, they should keep a recognisable display interface and use consistent terminology and visual guidance. Something like "Ascend Now" and alarms continuously.... then on reaching deco depth it shows "Stop Depth" with countdown. It stops beeping when you get to 5m and gives you the time to wait (as per safety stop info). It alarms and flashes whenever you ascend above, or drop below, that depth.

What is a recreational computer?

As for the alarms do we want; GET TO 3m NOW!!!!!!!!!

or: Hey, buddy extended safety stop

Judging from my own experiences, a large proportion of novice divers seeing that would assume that the 'Asc Time' was some continuation of their NDL limit. Scary, but not unrealistic.

Not unrealistic. Ascent time is an odd phrase, 'ceiling' is much more obvious.


I have had one instance where, out of a father and daughter buddy pair, the daughter had omitted a deco stop and locked the computer. But then this was a case of just following daddy to the surface rather than reading her own computer. If you don't even look at the computer then it doesn't matter what is it telling you.

 

[rhwestfall]

Judging from my own experiences, a large proportion of novice divers seeing that would assume that the 'Asc Time' was some continuation of their NDL limit. Scary, but not unrealistic.

likely because they didn't read the manual....... or did, didn't understand it, and didn't ask what the heck it meant....

 

[Jax]

Here, here, for what Andy says!

From what I have seen, on my tiny little subsample of dives, is that people do not understand their computer, nor do they know what to do when it fails!

 

[DevonDiver]

I can't look at that with anything but instructor eyes though. If I see ceiling my mind says limit. Will the average diver figure this out? I would have to say yes, we are all aware that a ceiling is limit.

Yeah, me too... but I have customers who educate me on how their eyes work... and it can be shocking

What is a recreational computer?

It's my fantasy. A dedicated computer for 'recreational' divers that does nothing more than get them to the surface after NDL is exceeded. Like the PADI tables do. No 'extra' info so that you can fudge yourself into a recompression chamber on the basis that "your computer said it was ok".

As for the alarms do we want; GET TO 3m NOW!!!!!!!!!
or: Hey, buddy extended safety stop

Somewhere in-between, I think.

Having seen divers blissfully ignorant of rapidly accumulating deco obligation, a little 'prod' wouldn't hurt.

The only dive computers that give that 'prod' are the air-integrated ones... because the computer calculates remaining air time versus deco obligation. Non-AI computers will happily let you put yourself into a lose-lose gas/deco relationship in the merry assumption that you know what you're doing.'

All that's needed is to remove the 'ascent time' and replace it with the instruction to 'ascend now'. Reach your stop, and it gives you 'mandatory stop' and a count-down.

That's as K.I.S.S. as it gets.

 

[Hawkwood]

That's what I draw on the board in my classes - an hour-glass with depth on one side and time on the other.