DCS due to reading computer wrong (I think)

[halocline]

I realise that I'll get probably get more flak following this post but those are the facts and I cannot change things that have already happened. Basically, I did not do anything different from any other diver on board except the major error during the ascent and safety stop with the SFM dive. As I have said many times, I realise that it was a big mistake, the consequences could have been more serious and I was very lucky that they were not. I will be more careful in the future and plan dives properly. I will not even consider any dive which is beyond acceptable recreational depths. Beyond that, I cannot do anything now; I am certainly not going to cut my own throat to appease anyone.

Finally I think you've hit the nail on the head with this post. I don't think anyone has been too mean to you, and we all appreciate your open-ness in posting this thread. Maybe you should consider taking some technical training; you're an experienced diver who has an obvious interest in diving spots that are really technical dives, and since you're a doctor, we assume you can afford it!

 

[vladimir]

Hintermann, if you're still following this Thread, I have a question. If you should decide to not answer publicly, I undertand.

I can't remember how many dives you had done ON THAT TRIP before you dove the SFM. Did you dive the day before you dove the SFM?

I wonder if there might have been a healthful impact if you had taken a non-diving day on the day before. Would a day of hydration and plenty of sleep before the dive had any impact? I don't know.

So, did you dive the day before? If so, what kind of diving did you do that day?

Thank you again for posting, Hintermann. You have helped promote safety in the diving community by posting here.

Ah, the persistent hydration myth. The known risk factors for decompression illness, according to this DAN article, are (emphasis added):

The main risk factor for DCI is a reduction in ambient pressure, but there are other risk factors that will increase the chance of DCI occurring. These known risk factors are deep / long dives, cold water, hard exercise at depth, and rapid ascents.
​

Dehydration falls into a different category:

Other factors thought to increase the risk of DCI but for which evidence is not conclusive are obesity, dehydration, hard exercise immediately after surfacing, and pulmonary disease.​

Which is not to say that a prudent diver should not ensure proper hydration. I just don't understand why so many people rank it so highly in the hierarchy of risk factors. I mean, we're talking about a diver who skipped deco stops—do you really think hydration was a big factor?

That aside, there is nothing stopping a diver from hydrating properly while diving during the day. Nobody needs a "day of hydration." Similarly, there is no reason you can't get a good night's sleep after diving all day. I sleep better after diving during the day.

A day to off-gas would have been a great idea, though. But again, probably not much help if you're going to skip required deco.

 

[DandyDon]

Ah, the persistent hydration myth. The known risk factors for decompression illness, according to this DAN article, are (emphasis added):

The main risk factor for DCI is a reduction in ambient pressure, but there are other risk factors that will increase the chance of DCI occurring. These known risk factors are deep / long dives, cold water, hard exercise at depth, and rapid ascents.
​

Dehydration falls into a different category:

Other factors thought to increase the risk of DCI but for which evidence is not conclusive are obesity, dehydration, hard exercise immediately after surfacing, and pulmonary disease.​

Which is not to say that a prudent diver should not ensure proper hydration. I just don't understand why so many people rank it so highly in the hierarchy of risk factors. I mean, we're talking about a diver who skipped deco stops—do you really think hydration was a big factor?

That aside, there is nothing stopping a diver from hydrating properly while diving during the day. Nobody needs a "day of hydration." Similarly, there is no reason you can't get a good night's sleep after diving all day. I sleep better after diving during the day.

A day to off-gas would have been a great idea, though. But again, not much help if you're going to skip required deco.

The hydration myth will be a lonnng time dying. It's generally the primary cause given for hits by Dr.P. on Coz and many other chamber docs in the Caribbean - and who's to dispute them even if they haven't updated their training since Y2K.

I think the obvious trigger is given in the title of the thread. An aggressive, week long dive trip without understanding his dive computer - with other contributing factors, one of which I am not allowed to mention.

Funny how those those misses play out sometimes. I knew a diver once who blew off 55 minutes of deco to help his buddy, fully expecting to be entering a chamber as soon as he got to the hospital - but they just watched him, and he never showed symptoms. They were in a well supported area in Canada tho, and his 55 minutes deco were planned - not a computer alert.

 

[Lorenzoid]

See Belize's Blue Hole - trips daily, similar approach.

This occurred to me. I've been considering starting a thread where people can list "million dollar dives" that the dive ops promoting them know or should know the average rec diver shouldn't be doing. To the SFM and Belize Blue Hole, I might add the Turtle Cave in Sipadan.

 

[Hintermann]

Maybe you should consider taking some technical training; you're an experienced diver who has an obvious interest in diving spots that are really technical dives, and since you're a doctor, we assume you can afford it!

There are 2 factors that stop me from doing this. First off, in the UK doctors are not even close to being 'rich' by American standards. Most of us work for the state owned NHS (which works very well by the way). You might say that I'm 'comfortably off' but no more.

Secondly, I have already decided to retire from diving in September 2015. I'll be 2 months short of my 60th birthday by then and maybe less than 3 years away from job retirement. There are quite a few land based holidays that my wife and I want to do while we still can afford to do so and my diving has taken too much vacation time in the last 6 years. I made a promise to my wife that after I retire from diving we will cover those overland places and I intend to keep that promise.

 

[themagni]

This occurred to me. I've been considering starting a thread where people can list "million dollar dives" that the dive ops promoting them know or should know the average rec diver shouldn't be doing. To the SFM and Belize Blue Hole, I might add the Turtle Cave in Sipadan.

Pfft, it won't happen to me.

 

[RJP]

Exactly. Because the operation allows and even encourages recreational divers to do this dive (remember that the OP believed that the dive plan had been discussed in depth during the briefing),

Either you are misquoting the OP (I don't feel like re-reading the thread) or the OP doesn't understand what a dive plan is.

I have done nearly sixty dives from the Odyssey. The captain and the crew of the Odyssey provide exquisitely detailed DIVE SITE BRIEFINGS prior to every dive. They do not, however, discuss a DIVE PLAN in any way. In fact they are very clear that they will NOT engage in any aspect of dive planning with or for passengers. They will tell you where things are - including depth - and they will tell you where they will lead tours, or they will take you on a specific tour if you like. But they do NOT offer a dive plan, suggest a dive plan, or help you plan your dive. The closest they will get to involvement in your plan is that they provide an MOD chart and an EANx log book.

 

[Hatul]

Good points made here and thanks to Hintermann for posting this and stimulating a good discussion.

While a deco dive should be planned out prior to diving, including gas management, the newer Uwatec Sol/Luna provide another safety net with AI. They display the Remaining Bottom Time, that still allows enough gas to made a safe ascent with all the required stops. When this number goes to 0 it requires the diver to start his ascent, and in this case would likely occur before the 15 minute bottom time.

 

[RJP]

Basically, I did not do anything different from any other diver on board except the major error during the ascent and safety stop with the SFM dive. As I have said many times, I realise that it was a big mistake, the consequences could have been more serious and I was very lucky that they were not. I will be more careful in the future and plan dives properly. I will not even consider any dive which is beyond acceptable recreational depths. Beyond that, I cannot do anything now; I am certainly not going to cut my own throat to appease anyone.

After everything that has been written in this thread, do you STILL not understand where and when your "major error" occurred?

Yeah, the error eventually bit you in ass at depth towards the end of the dive, but you MADE the error during your dive plan... or more precisely lack thereof.

[shakehead]

---------- Post added February 23rd, 2013 at 03:42 PM ----------

the newer Uwatec Sol/Luna provide another safety net with AI. They display the Remaining Bottom Time, that still allows enough gas to made a safe ascent with all the required stops.

How do these computers take into account:

• potential gear failures
• potential need for gas sharing with another diver
• potential increases in breathing rate later in the dive, such as the very high likelihood that a recreational diver will start sucking down air like crazy when he looks at his computer and sees that he has 10min of deco - and only 5min of gas - remaining

What is the "opposite of safety net"? Perhaps a pit of sharp spikes? Because that's what that "feature" amounts to...

 

[Hatul]

After everything that has been written in this thread, do you STILL not understand where and when your "major error" occurred?

Yeah, the error eventually bit you in ass at depth towards the end of the dive, but you MADE the error during your dive plan... or more precisely lack thereof.

[shakehead]

---------- Post added February 23rd, 2013 at 03:42 PM ----------



How do these computers take into account:

• potential gear failures
• potential need for gas sharing with another diver
• potential increases in breathing rate later in the dive, such as the very high likelihood that a recreational diver will start sucking down air like crazy when he looks at his computer and sees that he has 10min of deco - and only 5min of gas - remaining

What is the "opposite of safety net"? Perhaps a pit of sharp spikes? Because that's what that "feature" amounts to...

No one is saying is saying an AI computer is the panacea to safe diving. It's just an instrument to assist in making a safer dive, and I prefaced my comment that a deco dive should be preceded by making a dive plan. And by the way, no matter how well trained you are and how well you plan, I can always come up with a scenario that will kill you -- the point is one can make a dive safer but not foolproof.