Is 130 ft too deep?

[padiscubapro]

You're not saying that you would do that dive only carrying 80 cu ft are you? If you are, I'd like to see your gas plan.

With an RMV of 0.44 cu ft per minute you would suck the entire 80 cu ft on the bottom and that's without considering the use of any of the gas for ascent, decompression below 70 ft, any contingency gas or taking into account that you can't suck the tank completely empty.

First I normally wouldn't do it on a single 80 (except with 1 buddy in particular ) but I could easily do it ( which I did and had about 65bar when I reached my 70ft stop).. I have a very low rmv Here is a plan with an rmv 0f 0.35 which is higher than I normal see when I check my consumption rates.

I also know someone with about 1/3 the gas consumption I use.. He averages about 3 lpm which is about .11 cuft/min. I always kid him that he must have Gills

If I HAD to I would have no reservations about going on my 50% bottle at 100fsw.

Decompression model: VPM-B

DIVE PLAN
Surface interval = 2 day 0 hr 0 min.
Elevation = 0ft
Conservatism = Nominal

Dec to 165ft (5:30) on Nitrox 25.0, 30ft/min descent.
Level 165ft 24:30 (30:00) on Nitrox 25.0, 1.50 ppO2, 155ft ead
Asc to 100ft (32:10) on Nitrox 25.0, -30ft/min ascent.
Asc to 80ft (32:50) on Nitrox 25.0, -30ft/min ascent.
Stop at 80ft 0:10 (33:00) on Nitrox 25.0, 0.85 ppO2, 74ft ead
Stop at 70ft 2:00 (35:00) on Nitrox 50.0, 1.56 ppO2, 32ft ead
Stop at 60ft 1:30 (36:30) on Nitrox 50.0, 1.41 ppO2, 26ft ead
Stop at 50ft 2:00 (38:30) on Nitrox 50.0, 1.26 ppO2, 20ft ead
Stop at 40ft 3:30 (42:00) on Nitrox 50.0, 1.10 ppO2, 13ft ead
Stop at 30ft 4:30 (46:30) on Nitrox 50.0, 0.95 ppO2, 7ft ead
Stop at 20ft 7:00 (53:30) on Nitrox 50.0, 0.80 ppO2, 1ft ead
Stop at 10ft 12:30 (66:00) on Nitrox 50.0, 0.65 ppO2, 0ft ead
Asc to sfc. (66:20) on Nitrox 50.0, -30ft/min ascent.

Off gassing starts at 112ft

OTU's this dive: 79
CNS Total: 33.5%

63.3 cu ft Nitrox 25.0
20.6 cu ft Nitrox 50.0
84 cu ft TOTAL

 

[dweeb]

Nice to hear a "someone who lives outside the USA", type attitude, even if you don't. The whole thing about getting this cert, that cert, do this dive first, blah blah blah is just to provide lawsuit protection. Ther are other ways to learn that are just as effective.

Except he's not proposing to skip just the credential, but the training and experience part, too.

He's saying take a green, 30 dive neophyte, put her on trimix, and, with no more instruction than "follow me and do what I tell you," taking her to 160fsw.

 

[dweeb]

Remember the US Navy dive tables were written for strong, healthy men, in their late teens or early tewnties, and there is an expectation that adequate surface support is available.

And where a 5% casualty rate is acceptable in peace time.

 

[padiscubapro]

You are talking solo diving right? If you were to do this dive as a "safe" dive where you had enough gas for your buddy - that would not be enough gas. If you disagree lets see the numbers. Again, I could buy that only ise 80cu' of gas on the bottom, but to do the dive safely you would need allot more.

It depends on the buddy.. I know a few divers that can't even use "AIR" integrated computers without going crazy because they dont consume gas fast enough and get constant alarms.

The dive has to be planned with the whole team.. If I were to do this dive Solo, I would definately be on at least twin 80s, or my CCR.

 

[Mark Vlahos]

And where a 5% casualty rate is acceptable in peace time.

What good is surface support if you don't use it now and then. You need to give them some practice too.

Mark Vlahos

 

[MikeFerrara]

First I normally wouldn't do it on a single 80 (except with 1 buddy in particular ) but I could easily do it ( which I did and had about 65bar when I reached my 70ft stop).. I have a very low rmv Here is a plan with an rmv 0f 0.35 which is higher than I normal see when I check my consumption rates.

I haven't dived with many divers (ok none) who would be comfortable planning a dive based on an RMV of 0.35

 

[jbisjim]

Except he's not proposing to skip just the credential, but the training and experience part, too.

He's saying take a green, 30 dive neophyte, put her on trimix, and, with no more instruction than "follow me and do what I tell you," taking her to 160fsw.

Well I hope and think he was not serious on that.

 

[dweeb]

OK, I am a little more relaxed.
It sounds like the actions of the dive master in the water
were generally appropriate.

That's AWFULLY charitable.
SO he began to move upward. He was continuing the sightseeing, which means maintaining an ongoing risk that someone might wander off or otherwise create/experience a problem he no longer had the margin to deal with.

The actions of the dive master before the dive however were entirely inappropriate. By taking you on this dive, even if there had not been any equipment failure, the dive master put you at risk.

Amen that.

Wether you knew it or not this was a total "Trust Me" kind of dive.

But she should have known.

KAthy - heck no, it wasn't safe. Furthermore, if you have to ask, by most agency standards, let alone the probable opinion of many people reading this, you had no business being beyond 60 ft.

Just out of curiosity, since you apparently didn't know what should be done in that situation, did you know what the NDL was for that depth? Did you know what your contingency was for accidentally going deeper, staying longer? What sort of tank did you have? Did ANYONE in the group have a completely redundant air source?

When you decided to do this dive, just what did you think you would do if something went wrong? My guess is you just assumed the DM would handle it. You know what you do when you assume.

This decision mechanism really needs a closer look. What exactly made you think that the DM could save you from any mistake or mishap at a depth that 90% of the diving population is not competent to dive? Did he have a blue dive skin with a red and yellow 'S' on the chest? Did you witness him crushing a steel tank like a beer can on his forehead? In short, what readily observable attributes of the DM led you to believe he could save you from a situation you couldn't save yourself from? Did he have some extensive extra equipment you had never seen, and if so, did you ask any questions about it? yeah, so he had more training and experience - but did you ever stop to analytically consider what mere knowledge could possibly be a safety net for any problem you or the other divers, presumably novices as well since they blindly followed this pied piper DM on this journey into danger, could inadvertantly create?

Even now, I can hear the cries that I'm being too harsh, but we hear again and again about this sort of faulty decision mechanism to do a dangerous "trust me" dive, and it behooves us to determine its source. What is behind this willingness of people to blindly place their lives in the hands of others, with no empirical evidence of an incremental difference in objective capability, just because they have a title, an office, or some other credential? What about the current marketing, training, etc. of the current dive industry encourages this all to common phenomenon? Kathy, by now you should be realizing just how much risk you undertook. Think back - what made you believe, at the time, that it was reasonable, or what motivated you to take an unreasonable risk? If it's something you were told in training, then that something needs to change, fast.

 

[dweeb]

Well I hope and think he was not serious on that.

Go back and read all of Curt's posts on this thread.
I find no reason in anything he wrote to believe he's not as serious as a heart attack about taking her to 160. Sure, the helium remark may have been in jest, but only
because he was taking so much flak over the initial proclamation.

I can't tell you where I think his thinking on this originates - last time I alluded to it it was deleted.

 

[jbisjim]

Go back and read all of Curt's posts on this thread.

I have, and again I hope and think he was kidding. Or just trying to spur you a bit :06: