What if... [loss of buoyancy question]

[Bennno]

If my tank was too negative to enable me to be correctly weighted in the exposure protection I wear, I'd make some changes to my gear.

When you're on vacation you often don't have a choice. Some shops only have steels or ALs but not both. There are also still some older Fabers about in Egypt and the Med, that are very heavy.

 

[Diver0001]

./.. snip.../ That guy clearly had too much weight on him... or a kid or very skinny.
Unfortunately, these days, many instructors and shops tend to give people to much weight just so they have it easier.

As I said before, I and lots of other people used to dive without a BC and it works just fine as long as you only carry the amount of weight you really need.

I don't know. I had just met him 1/2 hour before. However, he was a German diver and the general impression that I have of German divers is that diver training in Germany must be relatively good because I don't see German divers making a lot of stupid mistakes. Moreover, I don't normally go nosing around the gear of people I don't know with all kinds of comments about it..... Maybe if we all did that more it would help but social conventions being what they are, I assumed that a diver (according to the list) with several hundred dives would know what he was doing.

We *were* in Egypt, however, so it's a context that he didn't dive in every day. There is a chance that he wasn't perfectly weighted since the configuration was very different to what he would have used at home.

In other words, all that I know is what I saw, which is that he was unable to regain neutral buoyancy after the BCD failed. He was able to hold his depth, more or less, by finning up but he was obviously struggling with it, perhaps due to the current, and I think he made the right decision to GTFO to the surface.

R..

P.S. as an aside, I have a massive allergy to "know it all" divers who sit behind a keyboard and level criticism on the actions of others. I've seen other things happen in Egypt too, to the point that a dive guide we had came to me in the evening, visibly distressed, because a couple of Dutch divers had leveled such massive criticisms of his response to an emergency during the dive I was on that he was shaken by it. This is someone who had 10,000 dives to the 50 that the Dutch divers had but they were so *sure* of themselves that they made the poor guy feel like he had made a massive mistake because he returned to the surface to fix it instead of fixing it under water.

The Dutch have a saying for these kinds of people. They say, (translated) "the best skippers are standing on the shore". This seems to apply to Dutch divers in Egypt but also to people on the internet.....

R..

 

[Diver0001]

I also have heard of this happening, and it's just another example of really stupid design for the sake of perceived convenience. Yanking on a weak rubber hose that you are relying on for buoyancy is not a good idea, yet the pull-dump encourages exactly that. You can't even turn upside down and inflate the BC because the pull dump hose is also the inflator.

Anyhow, glad you and your buddies survived. It does reinforce the idea of never being so heavily weighted with a single buoyancy source that you can't swim up. There's always another solution.

I don't think any of the divers I mentioned were in real trouble. In my case and in the case of my buddy who had the same problem we both communicated about the solution on the bottom and consciously decided what to to. In those two cases we took the time to examine the failure and formulate a plan.

In the case of the diver in Egypt, he clearly couldn't continue the dive with his BCD failed like that and decided to GTFO. The dive guide was the closest person to him and had already moved to intervene so even if he had continued to try fighting it, there would have been someone with him in a matter of another few seconds who could have helped him get back to the surface.

Those experiences have, however, formed me. At the shop I work I show my OW students the functions of the BCD, including the pull-dump but based on experience I strongly advise them NOT to use it. These three cases are not the only failures of the pull dump I've ever seen, just the the three that happened under water. For example I once had a student pull so hard on the pull dump during the buddy check that he broke the plastic coupling and my BCD leaked like a mofo under water, which I only noticed during the dive. I was able to finish the dive but that was the straw that broke the camel's back. Given the number of failures I've seen I utterly refuse to use it and I advise students to do the same.

If you ask me, a pull dump is a BAD idea. It's a BAD idea to use it and a BAD idea to teach it.

R..

 

[Bennno]

I don't know. I had just met him 1/2 hour before. However, he was a German diver and the general impression that I have of German divers is that diver training in Germany must be relatively good because I don't see German divers making a lot of stupid mistakes. Moreover, I don't normally go nosing around the gear of people I don't know with all kinds of comments about it..... Maybe if we all did that more it would help but social conventions being what they are, I assumed that a diver (according to the list) with several hundred dives would know what he was doing.

Three of the shops I used to work for had mostly German customers and I would guess that at least 8 out of 10 'vacation type' divers dive with too much weight. You don't have to check their gear, you can tell by how much air is in their BC and how fast they sink. I my experience, people are open to advice when they're 'offline'. I've had people go down from 6 to 2 kg or from 8 to 5 all the time.
Most instructors don't teach weighting as they should. One reason for that is, it requires more time and the 2nd reason is that you have a hard time kneeling with the proper amount of weight...
I know this because I did it myself, I used to give people too much lead because that how I was taught.

P.S. as an aside, I have a massive allergy to "know it all" divers who sit behind a keyboard and level criticism on the actions of others.

I assume you mean me and I'm sorry for your allergys. Eitherway, if you need to drop your weight to accend as a 'normal sized' person with a busted bcd, you're using too much weight!

 

[Diver0001]

Three of the shops I used to work for had mostly German customers and I would guess that at least 8 out of 10 'vacation type' divers dive with too much weight. You don't have to check their gear, you can tell by how much air is in their BC and how fast they sink. I my experience, people are open to advice when they're 'offline'. I've had people go down from 6 to 2 kg or from 8 to 5 all the time.
Most instructors don't teach weighting as they should. One reason for that is, it requires more time and the 2nd reason is that you have a hard time kneeling with the proper amount of weight...
I know this because I did it myself, I used to give people too much lead because that how I was taught.

I understand this, perhaps better than you know. I see instructors doing exactly what you are describing and I also hear novice divers saying that they *like* having a couple of extra kilo's because it gives them a better feeling of being in control. However every student is taught buoyancy checks and every diver does them. If a diver, like the one we're talking about, with 300-odd dives, carries too much ballast with them, then at some point it is no longer the FAULT of the instructor. It is, of course, the fault of the instructor if the novice does not understand the basics. But this example did not describe a novice diver.

Given that, do you see why I feel that the diver needs to be left to take his responsibility at some point?

I assume you mean me and I'm sorry for your allergys. Eitherway, if you need to drop your weight to accend as a 'normal sized' person with a busted bcd, you're using too much weight!

I don't know you well enough yet. On the one hand you come across as very experienced and on the other hand as very judgmental. You and I are different that way. I observe what I see and respond to my observations of events and you are much more assertive about your judgement of other people. In that way, I don't feel a "click".

Like I said, I have an allergy for "know it all" divers who are unnecessarily critical, particularly when they lack sufficient experience to back up their opinions. If you feel like I am addressing you then I can't answer to that. What I *do* see in you is your judgmental side. I've also seen you send the odd thread spiraling off into chaos. I personally believe from what I have seen that you have a lot to offer but at the same time I think that nobody learns much from criticism that is not constructive or ego based posturing, which is nearly ubiquitous on the internet, and to which neither you nor I are immune.

R..

 

[boulderjohn]

That's why you're not supposed to use heavy steels in wet suits... look up 'balanced rig' if you wanna learn more about it.

I have only seen that "rule" advised with steel doubles.

My reasoning presupposes that the diver is able to balance their equipment and avoid being overweighted, because that's what I'd do. If my tank was too negative to enable me to be correctly weighted in the exposure protection I wear, I'd make some changes to my gear. Because that's the only safe thing to do, especially for a "normally" experienced diver. YMMV, of course.

This seems to me to be self-evident. In a typical normal year, I will dive in a 3mm wet suit, a 5mm wet suit, and a dry suit. I will breathe from a single AL 80, a single LP 85 (Worthington), double steel LP 85s in a sidemount configuration, and double steel LP 108s (Worthington). To make all this work for weighting, I use either an aluminum backplate, a steel backplate, a sidemount rig, and a variety of weight configurations. With the double steel tanks, I always use my dry suit, because there is no way I can avoid being overweighted. With the single tanks, I have to change the amount of weight I use with each one. In the context of this discussion, if I am using a steel tank instead of an aluminum tank, I will simply decrease the amount of weight in the backplate, the weights I use, or both.

By the way, there is a difference even among aluminum tanks. A bit over a year ago, I was diving in a 3mm suit in Key Largo, and we did the deeper dives (like the Spiegel Grove) on nitrox and the shallow dives on air. When we checked out the tanks, I noticed that the nitrox tanks had a pressure rating of 3300 PSI, and the air tanks had a pressure rating of 3000 PSI. I asked if there as a difference in buoyancy, and the tank fillers assured me they were exactly the same. I checked via my smart phone and discovered that, no, the 3300 PSI tanks were nearly 4 pounds less buoyant. So my friends and I simply wore 4 pounds less when diving with nitrox and were just right.

 

[Bennno]

However every student is taught buoyancy checks and every diver does them. If a diver, like the one we're talking about, with 300-odd dives, carries too much ballast with them, then at some point it is no longer the FAULT of the instructor.

When you look at the run-of-the-mill vacation type dive shop in Egypt, Spain, Thailand or wherever. The vast majority of customers have less than 100 dives. I wouldn't be surprised if 80% have less than 50 or even 30 dives. I very much doubt that every stundent is taught a buoyancy ckeck and you or I hae no way of knowing that.

I understand this, perhaps better than you know.

Ironically, you're calling me judgemental a couple of lines futher down the same post.

I don't know you well enough yet. On the one hand you come across as very experienced and on the other hand as very judgmental. You and I are different that way. I observe what I see and respond to my observations of events and you are much more assertive about your judgement of other people.

What I find very aggravating about Sb is that it's very cliquey and lots of poor and one-sided advice is given to beginners by the 'heavy' posters and mods... everybody needs to buy a BP/W (and it's gotta be DSS of course), PADI is fantastic and you can't start too early with your PADI tec training (and here is a like where you can book), whenever something is wrong it's always the divers fault and never the agency or the instructor, yadi yadi yada... yet, if you utter an opinion that not to their liking, the SB 'experts' start whining and reporting.
When I call something BS, I do so because I think it's BS. What do you want me to do? Beat around the bush in a 500 word post, so a SB 'expert' doesn't feel like he's been criticized?

Look at this thread. The OP asked whether it's a problem when your BCD craps out. The answer is NO, not when you dive with the proper amount of weight! It's not a matter of opinion and no anecdode changes that fact. I explained this without attacking anyone, but yet again, the SB crew seems to have an issue with that.

I think that nobody learns much from criticism

You can't be for real.

 

[Bennno]

I have only seen that "rule" advised with steel doubles.

Doesn't matter whether you dive doubles, single tank or sidemount. It's not a rule, it's physics.

 

[boulderjohn]

I very much doubt that every stundent is taught a buoyancy ckeck and you or I hae no way of knowing that.

The weight check is part of the standards for every dive organization I know. For PADI it is supposed to be taught during confined water dive #2, and it is supposed to be done at the beginning of all 4 OW dives. A student who was not taught to do a weight check was taught in violation of standards.

That being said, a lot of students are indeed taught in violation of standards. That is because teaching students to learn skills and then demonstrate them during the dives while they are planted on the bottom while kneeling requires them to be significantly oveweighted. I know of instructors who do the weight check in the pool as a formality, tell the students they are overweighted but need to be overweighted while they are in the class so don't worry about it.

 

[Bennno]

...it is supposed to ...

Exactly!