Beware lunatic divemasters

[Russoft]

Because that's what I do when some parts of a story seems weird... the "EYE" witness wasn't an eye witness at all.. he "heard" they were in deco... they "say" they would go into deco if they saw something nice... That's why i'm asking what did his computer show... not there's. He doesn't know if they were really in deco or not. Since he says he aborted the dive prematurely so he wouldn't go into deco i'm expecting to hear he was close to it... If i don't have two sides of a story i like to make sure the one side i have makes sense

I have no idea. I was diving in the grey zone between diving the dive tables and trusting the DM (which is stupid, I know). I've been reticent to buy a computer as I was trained in the old days when almost no one owned a computer (and they're pretty expensive for the occasional diver), but I'm quickly realizing times have changed. That said, my log book says 28 meters for 37 minutes. I don't remember that dive profile very well. In any case, the DM and 12yo were pushing an hour BT by my watch. I was on the boat long enough to get sea sick...and I rarely get sea sick so it must have been a lot of waiting. No idea if a 20 min deco obligation is possible for that sort of dive. Maybe they exaggerated the story, but I do know that the 12yo kept yapping about it into the evening when we were doing a briefing for the next dive... her father asked she have another buddy for the next day. NO idea why he'd make such a request...

But when you're hearing something second hand, I understand not taking someone's word for it. I did try to tell the story accurately, but it's possible I'm biased by the fact that I had a less than positive experience.

 

[phoenix31tt]

I have no idea. I was diving in the grey zone between diving the dive tables and trusting the DM (which is stupid, I know). I've been reticent to buy a computer as I was trained in the old days when almost no one owned a computer (and they're pretty expensive for the occasional diver), but I'm quickly realizing times have changed. That said, my log book says 28 meters for 37 minutes. I don't remember that dive profile very well. In any case, the DM and 12yo were pushing an hour BT by my watch. I was on the boat long enough to get sea sick...and I rarely get sea sick so it must have been a lot of waiting. No idea if a 20 min deco obligation is possible for that sort of dive. Maybe they exaggerated the story.But when you're hearing something second hand, I understand not taking someone's word for it.

and that is reasonable... and it does make much more sense now knowing you were diving with tables...

 

[Nemrod]

I have no idea. I was diving in the grey zone between diving the dive tables and trusting the DM (which is stupid, I know). I've been reticent to buy a computer as I was trained in the old days when almost no one owned a computer (and they're pretty expensive for the occasional diver), but I'm quickly realizing times have changed. That said, my log book says 28 meters for 37 minutes. I don't remember that dive profile very well. In any case, the DM and 12yo were pushing an hour BT by my watch. I was on the boat long enough to get sea sick...and I rarely get sea sick so it must have been a lot of waiting. No idea if a 20 min deco obligation is possible for that sort of dive. Maybe they exaggerated the story, but I do know that the 12yo kept yapping about it into the evening when we were doing a briefing for the next dive... her father asked she have another buddy for the next day. NO idea why he'd make such a request...

But when you're hearing something second hand, I understand not taking someone's word for it. I did try to tell the story accurately, but it's possible I'm biased by the fact that I had a less than positive experience.

You cannot compare tables and computers. It is possible to do dives over a 100 feet or more and go nearly 1.5 hours total time and I have done it many times and on an 80cf, especially in Cozumel where the walls allow deep initial depths and the proximity to shallower areas, you may wind up in ten feet of water more than an hour later. That same dive on a basic, simple square profile tables would be 25 minutes. Even divers who are expert at multilevel cannot do those kind of times, well, not easily anyways and a good deal of planning and discipline to stay within the plan. Computer divers routinely ride the bar graph, we can argue the wisdom of that but it is nonetheless common. It is what finally made me abandon the tables for recreational diving, you/I cheat ourselves of so much valuable dive time. You need a computer and you need nitrox cert if not advanced nitrox eventually. In any case, a computer (with nitrox capability) is invaluable and a argument can be made you need two. I have one of the Oceanic Buds as back up but in lieu of that I often still carry a depth gauge and always a watch and I know the tables by rote memory including the ability to do basic on the fly multilevel calculations. And yes, you are wise to always have a basic dive plan, computer or not, and you are not at all wrong to want to stay within that plan.

Again, we can argue the wisdom, but it is easy to go into deco on a computer and then move shallow(er) and knowing that you will off gas and the computer will credit you for the shallower depth. I have many times bounced into deco from which a direct ascent is not immediately possible but which simply moving shallower quickly erases the debt. Foolish or not, I am certainly not recommending doing this (especially without some technical experience and equipment) but it is nonetheless routine for experienced divers to do exactly that, right or wrong is another thread. Riding the computer is very common.

N

 

[The Chairman]

I still don't get the issue over whether the girl went into deco for twenty minutes or two minutes. As a guide, it's my job to keep all of my charges comfortable and safe. He failed miserably here as attested to by the OP. Unless it's a tech trip, why would I allow, much less encourage any cavalier deco diving. Why badger the OP over such minor, minor points? You're straining the gnat and swallowing the camel.

DMs do push people into diving beyond their comfort zone all the time and I have a problem with that. It's type of intimidation where they use their experience as a lever to force these people to go farther than they would like. Many new divers are used to trusting their instructors, so they try to trust the professionals taking them diving. It's hard for them to speak up about this, and here people are grilling the OP rather than being outraged at the pro.

Again: you can call a dive at any time, for any reason, no questions asked and no repercussions. Speak up if you don't feel comfortable with the dive plan. Refuse to go if you still don't like it. It's your dive and your life. Don't let anyone endanger you needlessly.

 

[The Kraken]

The first thing I teach my students is that they should never hesitate to call a dive, for what ever reason.

The amount of money spent on a dive is not worth putting one's health/life in jeopardy.

You have been trained to make decisions. Rely upon your training. Be your own master.

Safe dives . . . . . .
. . . safer ascents !

the K

 

[phoenix31tt]

I still don't get the issue over whether the girl went into deco for twenty minutes or two minutes. As a guide, it's my job to keep all of my charges comfortable and safe. He failed miserably here as attested to by the OP. Unless it's a tech trip, why would I allow, much less encourage any cavalier deco diving. Why badger the OP over such minor, minor points? You're straining the gnat and swallowing the camel.

DMs do push people into diving beyond their comfort zone all the time and I have a problem with that. It's type of intimidation where they use their experience as a lever to force these people to go farther than they would like. Many new divers are used to trusting their instructors, so they try to trust the professionals taking them diving. It's hard for them to speak up about this, and here people are grilling the OP rather than being outraged at the pro.

Again: you can call a dive at any time, for any reason, no questions asked and no repercussions. Speak up if you don't feel comfortable with the dive plan. Refuse to go if you still don't like it. It's your dive and your life. Don't let anyone endanger you needlessly.

Nobody is arguing that the op has a valid point and that he did the right thing by insisting on a dive he was comfortable with... Me and others just wanted to clarify if the person actually went into deco based on the ops own deco obligation, he clarified he was diving tables which could mean the dm never went into deco at all, hell he could've been pulling the ops legs (as I said before I've heard dms joke about those things never do it). Pushing somebody past there comfort zone and recklessly endangering somebody's life by sending them into deco are two different things. I see the former all the time. I guess for me I just want to believe that there aren't dms out there crazy enough to send a 12yo into any type of deco... Maybe it's me looking for the good in others instead of just making up my mind that people could be that reckless with another person's life... That's just me


BTW.. You're kidding with the grilling right? One question? Without any type of aggression?... The OP took no offense to it why are you?... Ease up

Sent from my iPhone using Tapatalk

 

[The Chairman]

First, you weren't the only one grilling, er questioning the OP. I didn't like how it was coming across en mass and I thought everyone should 'lighten up'.

While I don't attribute any nefarious intent to the dive master, I have personally seen too many of them with a cavalier attitude towards limits, both personal and industry wide. To paraphrase Dirty Harry: "A diver's got to know his limits!" New divers have an especially hard time with this and all too often an overly eager DM will blur the lines even further so that the diver has no perspective on what they should or shouldn't be doing. They shouldn't be joking about putting a teen into 20 minutes of deco and I doubt if many of them would do that as they know they crossed a line.

 

[Oldbear]

... "A diver's got to know his limits!"...

"And as a Professional Dive Guide the DM got to know his customer's limits!"

To me, as this thread exemiphies, there are times when trust is misplaced in an misguided DM.

 

[The Chairman]

"And as a Professional Dive Guide the DM got to know his customer's limits!"

... and respect them.

 

[scagrotto]

Then I realize we're swimming into the current. Someone dropped us on the wrong end of the reef. So we swim against the current. I watch as my depth gauge drops below 20 meters, then 22, then 24. Who plans a dive with a shallow to deep profile?

Would you have preferred to deliberately swim against the current if that's what you had to do to start at the deep end of the reef? All dives start by progressively getting deeper, and they all end by ascending back to the surface. There's no reason any part of that has to happen quickly, other than being fast enough to finish before you've run out of air. You don't want a sawtooth profile, but AFAIK the whole deep first thing is related to the limitations of using tables to calculate NDL. The flip side of using tables to calculate a 100 minute dive that starts with 20 minutes at 100' is that if you start by spending 20 minutes at 30' and then descend to 100' you'll exceed the table's 20 minute limit for a 100' dive the instant you hit 100' (really 90.1' , since you should treat that as 100, and you'll already be at least a little past 20 minutes). Your computer can figure it out very easily. That's somewhat similar to what RJP is referring to in this:

it's very possible for a diver's computer to indicate that they are (or soon will be) in a deco situation at a certain depth... without that REALLY being the case based on the dive plan. This might be due to the computer not knowing what the REST of the dive looks like.

Other than all deco theory being, well, theoretical, and different algorithms disagreeing, I'm fairly sure that being in deco is a bit like being pregnant. It's a simple black and white distinction: you are or you aren't. If you will soon be in deco you're not in deco even though that may change. If you are in deco, you're in deco regardless of what you've planned as the rest of your div. The only question is how the situation resolves.