How many decompression dives do you have?

[jj1987]

Something I've been debating posting, but I think I'm new enough at this that I'll gain some valuable insight here from some of your responses, so I'll go ahead.

When I first started deco diving not too long ago, obviously the fear of getting bent lead me to do a lot of reading up. From reading first hand accounts of being bent, I couldn't find any relationship between the deco algorithm used, and rates of being bent. Obviously this doesn't mean a lot, since very few people will admit to being bent, and if they do, I doubt they'd admit to violating a profile, screwing up their tables, or messing up avg depth. Honestly if you look at minor details of messing up a deco algorithm, it really doesn't throw your schedule off too much (maybe a few minutes?), so I'm guessing most cases aren't due to these factors.

One thing I did however notice, was that a surprisingly high number of cases were occurring on vacations. My own inference here is lack of sleep as well as dehydration (drinking the night before the dive?), but I'm just throwing that out there to see if others think it might be something worth considering?

I've also found it interesting to see HOW different people pad their safety margin.

Some work out and stay in shape, drink TONS of water (even bringing camel packs for during the dive), ensure they're diving dry with plenty of exposure protection to stay toasty warm, do at least 5min surface deco debriefing the dive, and get a good nights rest before any deco dive. From what I can tell, most of those who fall into this group don't pad their deco schedules much. Others will add 5min to their o2 time or something along those lines, or pad their overall schedule with time.

GUE has an interesting dvd about decompression, that if you haven't seen it, is worth your time and whatever they're charging for it these days. Much of it is over my head, but it does go into details of why decompression sickness remains such a mystery, and theories that are being tested to prevent it.

[FW]

One thing I did however notice, was that a surprisingly high number of cases were occurring on vacations. My own inference here is lack of sleep as well as dehydration (drinking the night before the dive?), but I'm just throwing that out there to see if others think it might be something worth considering?

Possibly they do most of their diving while on vacation. Not to mention more repetitive dives.

[FW]

3) I do a few minutes substantially shallower than my computer suggests. At Ginnie, if my first stop is at 30, I spend about 5 mintues at 50 first.

?? Deeper maybe?

[aainslie]

Yeah... OK, on that, I DO also try to hug the ceiling all the way to the bench - after that I change my strategy and hug the FLOOR, and move slowly. If I have a scooter I don't use it between the lips and my 50 ft stop. I start moving VERY slowly basically from the bench/keyhole on out.

Also this is on shorter Ginnie dives. In the deep section (I hit 167 ft, apparently it goes a little deeper), I often have a formal 50 ft stop by the time I get back to the lips. Of course, the whole passage from the Henkel out is a nice deco from that deep bit. Then I stop before the lips, just after the keyhole, for a few minutes in 60-70 ft. Puzzles the crap out of incoming groups, they sit there signalling at me to come past them, and on at least one occasion it tok a LOT of signalling to convince them to come past me. Good manners gone nuts

But you're right, I could start earlier. Key thing is, the computer's suggestion that 30 ft is cool is often NOT cool. nd it pays to slow down a LOT during the exit.

[FW]

shallower

What I meant by "deeper?" was you said "shallower" in your other post.

[aainslie]

What I meant by "deeper?" was you said "shallower" in your other post.

D'uh - sorry, I missed that!

[Bob Cree]

Yeah... OK, on that, I DO also try to hug the ceiling all the way to the bench - after that I change my strategy and hug the FLOOR, and move slowly. If I have a scooter I don't use it between the lips and my 50 ft stop. I start moving VERY slowly basically from the bench/keyhole on out.

...But you're right, I could start earlier. Key thing is, the computer's suggestion that 30 ft is cool is often NOT cool. nd it pays to slow down a LOT during the exit.

Perfect!

In the deep section (I hit 167 ft, apparently it goes a little deeper), I often have a formal 50 ft stop by the time I get back to the lips. Of course, the whole passage from the Henkel out is a nice deco from that deep bit. Then I stop before the lips, just after the keyhole, for a few minutes in 60-70 ft. Puzzles the crap out of incoming groups, they sit there signalling at me to come past them, and on at least one occasion it tok a LOT of signalling to convince them to come past me. Good manners gone nuts

2) I use GF 15/80 and VPM B/E conservative 5.

Having observed a part of one of these dives and on deco, I am curious what software you use to generate the GF 15/80? Given, there are plenty of unknowns on my part to be sure, but I believe (my) decoplanner using GF 20/80 would have resulted in a bit longer deco than what I observed - so I just assumed you were diving the computer (which I routinely find are significantly less conservative). Now, since learning you use GF 15/80, I am wondering if there is a significant difference between different software packages as well.

As a point of comparison, decoplanner 30% Nitrox, 110 feet square profile for 140 minutes w/100% O2 deco gas gives 106 minutes deco and 159% CNS. Since computation is our primary defense against getting bent, what software are you using and how does it compare?

Why I bring this up is that we all tend to follow our software - whether real time or tables - some conservative, others less so...do we truly know what it means? My bet is we are diving less conservative out of ignorance...and your polll data suggests that - biases and all. I think we are all just a bunch of human guinea pigs.

Glad to see you are using the 15/80 - I think it makes alot of sense for chronologically challenged divers.

[Bob Cree]

And yet everyone seems to opt for schedules to 'rush out of the water'.....

I agree with Sludge...Profound indeed...

After all, why the heck do we want to leave someplace we all try so hard to get to?

Is it because we are in such a big hurry to refill and get another dive in? Hmmm, now that I think if it, interesting link to what Rich said...if you are in an all fired hurry to get out and refill for another dive - seems there is a link to repetitive diving and exertion...

higher quality...lower quantity

[aainslie]

On your first post - I use GF on my Vision on the Inspo.

On the second - are you kidding me? Deco is excruciatingly boring!

[atedeschi]

i feel like my profiles are like dare devil profiles to what I am hearing. I use Vplanner on nominal, and usually throw a min or two in at half my max depth and a 5min saftey stop added to my last stop.