Challenge (easy one). Deco.

[WJH]

Ok, I'll add to this one. Sneak diving, walked a very long way up a spring run with my buddy dragging a canoe and our gear. When we got there my buddy had forgotten his two computers. It was a very hot day so no way were we going back. He took my computer and I took my tables and bottom timer. We dropped into a S shaped opening. I was upside down and digging my way into a fantatic sidemount cave and guess what? I see a marble. Of course I had to have it and as I was stuffing it into my pocket, my tables blew away...I thought, OK well we can deco off my computer. I didn't know my computer had died and my buddy thought, OK we have tables and we can deco off those. To justify this a little it was hot, a great cave, a sneak dive etc....I know, no excuse but we did it! We did 90 minutes, max depth of 110, no tables or computer for deco. Without cheating..What would you do? Cindy

You do have some serious adventures, Cindy. Not sure whether I would love to go diving with you or if I would be afraid to go diving with you. LOL! OK, I'd love to dive with you--but would be sure to bring a buddy bottle and redundant everything.

WJH

[Cindy]

Bring redundant everything! The way we dive and the places we go truly does eat gear!!

[DeWayne]

Deleted since it no longer applies to this thread

[Cindy]

I took most of my post off, DeWayne. Thanks for the compliment but I was breaking my own rule on that one! Cindy

[ARY]

I personally liked this one:

50ft, 1m
40ft, 1m
30ft, 2m
20ft, 7m 99%
10ft, 7m 99%


I assume backgas is 32%. and I have deco gas available.

I then asked v-planner, and got much less deco time, and no deep stops.

Here is my paln (gas is 32% but if the He comes at bargain price i'll take 30/30):

DEPTH__TIME,_STOP,___GAS,__PPO2
FT___M___min__min_____o2%_____
100__33__90___________32___1.29
90___29_________1_____32___1.19
80___26__92_____1_____32___1.1
70___23__93_____1_____32___1
60___19__94_____1_____32___0.9
50___16__96_____2_____32___0.8
40___13__98_____2_____32___0.71
30___9___100____2_____32___0.61
20___6___112____10____100__1.61
10___3___114____2_____100__1.3
0____0___116__________100__1

TOTAL DECO, min=22
TOTAL DT, min=116

V-planner actually gave me 19 mins w/longer stop at 20' and shorter deeps stops. Like DeWayne said i tried to implement method from that article in I-net.

Aanslie, i would freez my butt now in a drysuit doing it that long. Couple years ago i was able to handle that kinda deco in wetsuit but even reminding that makes me shivering

Cindy, too bad your post is gone but i caught a chance to read it. You are reading between lines, and thinking clear, i guess that is why you can see small tunnels where many people would just swim by.

[aainslie]

Aanslie, i would freez my butt now in a drysuit doing it that long. Couple years ago i was able to handle that kinda deco in wetsuit but even reminding that makes me shivering

I agree, but would you rather be bent or cold? The thing is, over-decoing doesn't carry any real penalties other than a bit of cold and boredom.

Divng is always about risk mitigation. This is a good example of where you can reduce risk almost costlessly. Usually there's a price - increase the PO2? Decreases deco but increases O2 exposure. Independent cylinders (i.e. sidemount)? Increases redundancy but increases complexity. And so on and so forth.

Here where you really have to guess, adding time is pretty costless.

Plus I did 50 mins deco in Ginnie in a wetsuit - after a 2 1/2 hour dive - and survived that. So this can't be that bad.

Andrew

[Cindy]

I kind of like deco.

We ended up doing close to the schedule that Andrew suggested. THen we added 15min. just to be sure. When we got back to the dive log said it was only 5min more than my buddy John's dive log showed he had done on a previous dive. We just made a guess. But we had both been diving a lot of dives at that time there had the same profile. What I would do if I didn't have that much time and experience at that depth would be to just use up my little oxygen tank. Better cold than bent. Especially when you are sneak diving out in the middle of the woods without cell phone or a chance of help without going to jail.

Of course I don't do that anymore, I reformed...Cindy

[rjack]

Not a single ratio deco answer??? I'm disappointed.

RJ

[Cindy]

Not a single ratio deco answer??? I'm disappointed.

RJ

Oh! These guys all know how really crappy at math I am! If I don't have a computer or tables you can just figure I have to guess. I don't have enough fingers and toes to figure those cool deco ratio's on the fly! Being born blonde has been a constant burdon to overcome in my life. LOL,
Cindy

[rjack]

Ok here it is.

Air (sucks):
with 110 max I assume the average is 100ft
02 only for deco
BT = 90 mins

no deco at 100 is 20 mins, 90-20 = 70 mins over no deco limit

2min deep stops start at 75% of depth
70-2
60-2

switch to 5 min deep stops at 50% of depth
50-5
40-5
30-5

Then...
One half of backgas deco time (70/2) = O2 time
20-35mins total

3 air breaks in there count towards total deco time so
12-6-12-5 would be the routine

then a slow 6-10 min ascent to surface on O2

Ratio gives alot more time deeper, backgas breaks, and all the shallow time at 20.

Questions? I'm only Tech1 and 70min obligation is a bit beyond those limits, but that's how I'd do it.

RJ