I f*** up and I am ashamed

[Dody]

Damn, you are having a rough go at it recently! I've never had to swim for 2 hours to make it back!

It was fun. Except from the lateral current. My wife and I are pretty fit. The DM struggled though .

 

[Dody]

Hi @Dody

Let's try again. I'll start with a story of my own. I dive a back inflate BC and an AL80 cylinder. I have been diving a 3 mm full suit +/- a 5/3 mm hooded vest for many years through many new wetsuits, with 8 pounds of weight. This allowed me to be neutrally buoyant at my safety stop and then make a nice, slow, controlled ascent to the surface. I recently bought a new 3 mm full suit with a different construction material (Henderson Greenprene). On my first dive in this suit, I found it very difficult to hold the SS and control the ascent. I added a pound of weight for the next dive. This was much better but I was still borderline weighted. I added one more pound of weight and this works well. So now I dive that suit with 10 pounds, rather than my previous 8

It's not how much weight others think you need, or even what you think you need, it's what you really need, based on a valid weight check at the end of your dive. If you are properly weighted, you should not have a problem descending. The weight of gas in your cylinder, that you will consume during the dive, weighs 5 or more pounds, depending on your cylinder size. Trapped air in your BC or wetsuit may impede the descent.

So what bothers me, and perhaps others, is that one would think that the information above would have been taught to you and incorporated into you diving during any or all of your training, up to divemaster. How would you advise others in checking their weighting?

I am a new diver. And I am still learning. But my nature is that I only accept what can be proven. Instructors told me that I should dive with 2 Kg. I am very thin. Of course, I will make mistakes, hopefully not lethal ones. This whole story about weight, I agree that I was wrong. But make no mistake. I was told to dive with as little weight as I could. I am a DM but I don’t feel like being good enough to be responsible for the life of others. I just don’t have the experience. So, instead of bashing me, can you try to make sure that I get the experience I need to become a better diver?

 

[boulderjohn]

His point was that if you are underweighted at the end of a dive, you will have an uncontrolled ascent, and there will not be much in the way of skills that will prevent that from happening. A diver I know had a buoyancy control issue at about 90-100 feet after a middling tech dive. He was a long time tech instructor, even a cave instructor. As he went to the surface, he did all he could to stop the ascent, but he could not stop it. He said he assumed he was going to die. He didn't die, though. It just took 3 months in a rehabilitation hospital for him to be able to walk again.

Sorry for your friend. But can you tell me how you can have such a problem without losing your weight belt or being caught in an upstream current? Just want to learn.

I don't know how a diver with that much experience lost buoyancy control on that dive, because when he told me about it, he did not know, either. The key is that it happened to an extremely experienced diver--they are not immune.

One small possible factor may have been his tendency to resist learning information that conflicts with his previous beliefs. He had been told emphatically by people he admired that altitude did not have to be considered on dives. On a dive we did together at about 11,000 feet/3,300 meter elevation, I talked about problems we had with buoyancy in shallow water, and I talked about the significant difference between buoyancy at that elevation and buoyancy at sea level, and he dismissed my statement, saying there was no real difference, despite the simple math of Boyle's Law. The dive on which he was paralyzed was at a significantly higher elevation than our previous experience together, and when we talked about it, I asked him if he knew the difference at that elevation according to Boyle's Law. He had not given it a thought. At sea level, a bubble of air at the depth where he had his trouble will increase 4 times when it gets to the surface; at the elevation he was diving, it will increase 7 times. I think that is significant, even though the difference at depth is not as great as that. Because his mindset was that altitude is not a factor, he had failed to take that into account.

 

[Dody]

Don't know if your using sarcasm or not, but deflating a BCD and having proper trim and weight should have been covered on day one...<TG>

And it is.

 

[boulderjohn]

My DM course was one week long .But I had done the Rescue course before and it took two weeks.

My DM course through PADI took a couple months. I have taught DM courses. I cannot imagine getting through one in a week unless maybe it was 7 full days of work.

 

[Dody]

I don't know how a diver with that much experience lost buoyancy control on that dive, because when he told me about it, he did not know, either. The key is that it happened to an extremely experienced diver--they are not immune.

One small possible factor may have been his tendency to resist learning information that conflicts with his previous beliefs. He had been told emphatically by people he admired that altitude did not have to be considered on dives. On a dive we did together at about 11,000 feet/3,300 meter elevation, I talked about problems we had with buoyancy in shallow water, and I talked about the significant difference between buoyancy at that elevation and buoyancy at sea level, and he dismissed my statement, saying there was no real difference, despite the simple math of Boyle's Law. The dive on which he was paralyzed was at a significantly higher elevation than our previous experience together, and when we talked about it, I asked him if he knew the difference at that elevation according to Boyle's Law. He had not given it a thought. At sea level, a bubble of air at the depth where he had his trouble will increase 4 times when it gets to the surface; at the elevation he was diving, it will increase 7 times. I think that is significant, even though the difference at depth is not as great as that. Because his mindset was that altitude is not a factor, he had failed to take that into account.

You really scared me. I will study the altitude aspect.

 

[Dody]

My DM course through PADI took a couple months. I have taught DM courses. I cannot imagine getting through one in a week unless maybe it was 7 full days of work.

It was a 7 full days of work. But as I said, was it enough?

 

[boulderjohn]

Exactly. But some people tend to believe that even though you deflate using all the available means, you still have air in your BCD.

I think what you are missing is what many newer divers miss. You can use all the possible dumps on your BCD and still have air in your BCD because air can be trapped in places that prevent it from getting to the dump. Air wants to go up to the highest point in the BCD. If it has to go down to get from one place to another, it isn't going to happen. You can have an enormous bubble a few centimeters away from a dump, but it will not get there if there is something in the way (a fold or crease in the wing) or if it has to go downward to get there.

 

[Dody]

I sometimes have a dream. More than a nightmare. I dive and I turn so see my wife and she is weird. I fin to get to her, make sure that she still breathes through her regulator and then ascend as fast as I can. In this scenario, there are good things and bad things.

 

[Dody]

I think what you are missing is what many newer divers miss. You can use all the possible dumps on your BCD and still have air in your BCD because air can be trapped in places that prevent it from getting to the dump. Air wants to go up to the highest point in the BCD. If it has to go down to get from one place to another, it isn't going to happen. You can have an enormous bubble a few centimeters away from a dump, but it will not get there if there is something in the way (a fold or crease in the wing) or if it has to go downward to get there.

I understand that very well. Not only did I use the valves but I moved my body. Ass up. I am willing to accept the concept that there was some air trapped in my BCD. But the question is: how could I get it out?