Dive by computer?

[g1138]

How do u keep track of letter groups once you're off tables? Just assume your in the last group before your SI?

Assuming you're in the last group isn't a smart idea IMO. You could be way off by that assumption.

If I go off tables it's because I'm planning off my computer.

And if I go off tables, I stop looking at them completely. There's no need to look at them at all really since I'm planning off my computer in the first place. If I'm planning off of tables (and not off my computer) then I make it my priority to stay within my tables.

When I'm planning from my computer, I only look at my Tables from habit and as a backup should my computer fail. I'll want a gauge of my RNT even though I won't be diving for 24 hours.

If you go off tables then there's really no way to get back onto tables unless you wait 24hours and "clear" yourself of any RNT.

 

[rhwestfall]

[-]Your profile isn't clear to me, but based on how I read it:

Multi-Level using the PADI Wheel:

assuming first dive - begin a "A"

"A" then 40' - 5 min - "B" (NDL: 128/198) *first number is for ML
"B" then 75' - 5 min - "D" (NDL: 23/27)
"D" then 50' - 5 min - "F" (NDL: 51/61)
"F" then 20' - 20 min - "K" (used 35' here as that is the min depth on the wheel) (NDL: 154/169)

End - "K"

less than a 2 minute exercise.....

but this isn't 85 minutes -[/-]

 

[rhwestfall]

okay - think I got it (took 85-5-5-20 to get the time @ 50')

"A" then 40' - 5 min - "B" (NDL: 128/198) *first number is for ML
"B" then 75' - 5 min - "D" (NDL: 23/27)
"D" then 50' - 55 min - "W" (NDL: 51/61) - OUT OF ML Calculation range for safety of ML calculation.....- POTENTIAL PROBLEM
"W" then 20' - 20 min - "V" (used 35' here as that is the min depth on the wheel) (NDL: 41/56)

A little too much per this table.

DiveNav - what is the tissue loading look like at the peak of the "hump" in the NDL profile?

 

[rhwestfall]

On the air side: - 22.5 psi/min (this is a 0.6 if I remember correctly) & using the NASDS Calculator from some recent calcs on an AL 80 I did for someone.....:

250 psi
375 psi
3100 psi
725 psi

this dive didn't work at that consumption......

only took 2 minutes to do this....

 

[Thalassamania]

Rather than working out your letter group from the tables, record the scrolling no-D limits at the end of your dive, you can use those time/depth pairs to accurately shift over to a set of tables if you need to. Just use the pairs to come up with letter groups and take the highest group designator.

 

[racerx_]

Assuming you're in the last group isn't a smart idea IMO. You could be way off by that assumption.

If I go off tables it's because I'm planning off my computer.

I'm not assuming, I'm asking haha.. And mainly because you said at the end of the day you work out your pressure group, but also said sometimes you're off table. So was trying to understand what you do, as it relates to some recent questions I've had

Rather than working out your letter group from the tables, record the scrolling no-D limits at the end of your dive, you can use those time/depth pairs to accurately shift over to a set of tables if you need to. Just use the pairs to come up with letter groups and take the highest group designator.

This makes sense.. What do you mean by 'scrolling'

 

[Thalassamania]

Most computers have a dive planning feature whereby they flash your new no-D limit for each depth, in 10 foot increments. See: Mike Emerman's paper in: [h=1]Proceedings of the AAUS Dive Computer Workshop.[/h]

 

[Belce]

Dive computers are solid state electronics meaning they will fail to begin with or due to water in their circuits. Or if your dive computer worked yesterday it will work today. If it has a problem it will indicate it as part of the predive check and most common would be low battery. Dive computer is the single least likely to fail item you dive with. To improve your dive safety, I recommend you intergrate tank air pressure with your computer as well.

Diving people can be more than conservative when it comes to their safety and it is understandable. However technology has improved and advanced and today's computers are better.

if you are diving deco or non deco it is safer with a computer. If you are diving deco with trimix it is safer with a computer.

 

[racerx_]

Most computers have a dive planning feature whereby they flash your new no-D limit for each depth, in 10 foot increments. See: Mike Emerman's paper in: [h=1]Proceedings of the AAUS Dive Computer Workshop.[/h]

gotcha.. thats what i thought you meant, just wanted to make sure.

 

[Thalassamania]

Dive computers are solid state electronics meaning they will fail to begin with or due to water in their circuits. Or if your dive computer worked yesterday it will work today. If it has a problem it will indicate it as part of the predive check and most common would be low battery. Dive computer is the single least likely to fail item you dive with. To improve your dive safety, I recommend you intergrate tank air pressure with your computer as well.

Diving people can be more than conservative when it comes to their safety and it is understandable. However technology has improved and advanced and today's computers are better.

if you are diving deco or non deco it is safer with a computer. If you are diving deco with trimix it is safer with a computer.

I'd have to disagree, because of the rounding factor with tables they tend to mirror a more rigorous exposure than was actually experienced, computers, on the other hand, mirror rather precisely, the exposure that was experienced.