Genesis once bubbled...
It was a religious thing. I learned a lot from it and the time that I took from my life with it, and won't make that mistake again.
Hm. I wouldn't mind talking to you about it. Offboard, if you'd like. Shoot me a PM about it, if you're willing to share.
Very interesting.
I don't think it is materially better than anyone else's.
I couldn't tell you. I've never heard a DIR-ite claim a perfect safety record, and I have no idea what the statistics are. My gut feeling is that they are statistically safer than other agencies, but it'd be really interesting to know the actual truth. I wonder where something like that could be found, and if DIR training improves the (already admittedly statistically excellent) dive safety record
WKPP has lost several people over the years. At least one set of deaths has been reported in their progress reports. They have also bent a LOT of people. GUE in general has had people die, including most recently Far (from the west coast, expired here in Florida) and a GUE-trained cave diver who expired in Ginnie not all that long ago (suspected Oxtox hit). I've heard of others, but don't have the details.
I've heard of cases like this, usually in boards over casual discussion such as this. Do you have any proof? Any newspaper articles or anything?
I would love to have some actual stats... That might really be an answer for this constant DIR vs. non-DIR debate.
I have no idea what the real stats are. Like I said, my gut instinct says that statistically, DIR trained divers are considerably safer, but I would really like to know via the numbers.
How do you know that "They have bent a lot of people?"
I don't know of any agency that trumpets its failures, of course, so the lack of full disclosure is not an indictment - its pretty much SOP. DAN doesn't catalogue agencies when compiling their reports to the best of my knowledge either.
Jeez, that's a real shame. You would think that one of the first things they'd look for is the training agency that said that the injured diver could dive.
I'm doing a "virtual dive" followed by a "virtual flight" in the next couple of months at the DAN center at Duke University. I'm playing "Guinea Pig," and plan on having many conversations about deco theory with those on the cutting edge of that medical understanding. (Whatever "cutting edge" there is!)
Maybe this is a question that needs to be asked...
I like the trim and the pack "melting away" in the water - I don't even notice its there.
I'm with you on that one.
What I was really looking for is your choice of weighting and trim, buoyancy compensator style, and maybe even brand names. Do you dive a Hogarthian rig or an "open water" rig?
GI3 and the Fundamentals book both make the case for ALWAYS having ditchable weight - for the specific purpose discussed below.
I haven't heard that... Or read that. And the DIR-F class taught me specifically what I talked about in my last post, which was that YOU must decide exactly how much ditchable you need, if any.
I disagree [with the idea of needing ditchable weight], in that I disagree with the basic premise.
Agreed. I do most of my diving from a boat out in the middle of the ocean, where separation is possible. The only time I'd really be concerned about wanting to ditch weight is when I'm at the surface, waiting permenantly and indefinitely to be rescued (ie: I'm separated from the boat and lost) In this case, I could ditch anything that wasn't buoyant in order to ensure floatation, if I really needed to. Of course, first I'd have to be diving with no exposure protection whatsoever (which doesn't happen), I'd have to have a complete wing/BC failure (as in, "it will hold NO air, whatsoever), and I'd simultaneously have to be separated from the boat and have been able to get nobody's attention. It'd be a pretty far-fetched possibility, and even then I'd just ditch whatever was negative... Not to mention that I've always got a lift bag and sometimes a surface marker anyway.
No they don't. My SSI books didn't, and neither does a set of PADI books I loooked at. Both list that as an ABSOLUTE last resort. In fact, both make pretty clear that during an ESA, you DO NOT ditch until you get to the surface (THEN you ditch!)
Really? That's not how I remember it.
Page 92, DIR-F manual:
"...The diver should be able to remove enough weight (in the form of a weight belt or a canister light) to enable him to swim to the surface." Page 93, DIR-F manual:
"Removable weight that allows divers to remove some of their weight (as opposed to all at one time) allows greater control over a buoyant ascent... Depending on how much weight one needs, divers might choose to use a combination of a v-weight and a canister light. Nonetheless, it is important not to overweight the diving rig with too much fixed weight, because it will prevent one from "ditching"the weight..."
Nothin in there that I see says any special order that it must be done in... Like in class, the object in an ESA is to swim to the surface. If you're too heavy to do so, then you need to be able to ditch some of the weight in order to do so. Simple.
Page 93 continues:
"Far too many people assume that an easy solution to the weighting problem is to wear a lot of additional weight and then counteract that weight with oversized double wings. Not only will this 'solution' leave a diver carrying far too much weight, it will also put him/her in the same unenviable position of having to struggle with increased resistance caused by the unecessary drag of an oversized BC filled with too much air. As we mentioned earlier, trying to solve the weighting problem by resorting to a double BC system creates more problems that it solves because, while a diver is VERY unlikely to ever have a BC failure, the diver who opts for a double BC system will always be victimized by increased stress and task loading. Furthermore, should this system fail, that latter diver will be in substantially more trouble than the one who, from the outset, had configured their system to survive the loss of buoyancy." Sure, I realize that this sounds like I'm quoting from some sort of "bible." I'm not... It's just JJ, and it's just the opinion as he expressed it. I happen to agree with it, though, and for the same reasons he listed. I am sure that if you took the DIR-F class, the instructor would be willing to prove these points to you. That is, if you ever were interested in taking the class. Matters not to me. You mentioned it, and I'm simply telling you what DIR teaches, that's all.
There's more too, on choosing a cylinder... Page 94:
"Choosing the appropriate cylinder depends on several factors; e.g., body size, breathing rate, dive profile and diving environment. Selecting the wrong cylinder contributes to buoyancy control problems, and because of this, to environmental damage and diver risk. Failure to match the appropriate cylinders with the right exposure suit and buoyancy control system can also prove fatal. Most people find that Pressed Steel 104cf steel tanks are great for cave or cold water diving, where heavy thermal insulatoin and dry suits offset negative weighting. For longer dives or larger divers, 120's are also a popular choice. P>For ocean diving in a wet suit, twim aluminum 80's are the cylinder of choice. Divers should never risk their life by being over weighted at the beginning of a dive. If one needs more gas, then they should take an aluminum stage. The buoyancy characteristics of aluminum, especially when filled with helium, are such that ad added weight belt and/or canister ligth provides the necessary ballast that allows the rig to be only reasonably negative when full, neutral when empty, and capable of being swum if the weight is dropped. In cave diving, steel tanks are commonly used with a dry suit, because the must be negative enough to allow the diver to stay down in a low-on-gas emergency. There is nothing worse than being too light to stay off the ceiling while being low on gas and struggling. For this reason, prior to use, a rig must be balanced and weighted to accomodate a no-gas situation. P>Aggressive dives like those conducted in deep water or in overhead environments require ample reserve breathing supplies. Therefore, individuals often prefer larger volume, lower pressure, steel cylinders made by manufacturers like Pressed Steel and Faber; these generally have a working pressure of 2,640 psi. The lower pressure tanks do not require high pressure fills to achieve reasonable gas supply, but allow for higher volumes when necessary. This is especially helpful for partial pressure Nitrox and Trimix fills. Divers using steel tanks should use additional buoyancy in the form of a dry suit to protect them from BC failures."
Okay, a couple of things to note there... JJ does not say, "Dive steels when you're wearing a wet suit, and no more Kool Aid." JJ says, "These are the reasons why aluminum 80's are
the cylinders of choice when diving in a wetsuit." He goes further to show why he believes this. From my own humble experience, I agree with him. However, if you can plug in the numbers and get the correct buoyancy characteristics from whatever tank you choose, then so be it. Nobody said that diving steel in a wetsuit = "no DIR." JJ simply said that's what he believes, and this is why... I'm sure that if you showed JJ your math with your tank, he'd say the same thing I did... Can you swim up "X" number of pounds? Simple.
Also, note what he said at the very end about "additional buoyancy in the form of a dry suit to protect them from BC failures." Isn't that pretty much exactly what we were talking about? Who told you that a dry suit couldn't ever, under any circumstances, be used for buoyancy? And if this is the case, then why in the world would you need a redundant bladder? Why would you want to put up with the drag created by one?
Man, I didn't make this Kool Aid... And I can assure you that I didn't run up and just drink it... I studied it for a while until I finally said, "Lemme try it." It was different than I expected, even after all that I thought I knew about it. I really like it. I think you would too. But I swear, I couldn't care less if you had any or not. But so long as you keep staring at it and asking questions, I'll be happy to tell you about it.
The amount of weight you need to balance your rig at the surface with no gas (or very little) in the cylinders has NOTHING to do with the type of metal the cylinder is made of!
Oh, I agree completely. The only reason that material is even mentioned is because it's generally accepted that aluminum tanks are the most buoyant tanks you can have.
But however you cut it, you're absolutely right... It's got everything to do with exposure protection and how much gas you have. Everything else should be adjusted correctly from the beginning, and should be a moot point if you're weighted properly.
So you are, if balanced for neutral at the surface with empty tanks, going to be 28lbs negative at that same 100'! Can you swim up 28lbs? I probably cannot. I don't know if you can.
You know, I've never tried... It'd be an interesting thing to learn. I've set myself a personal limit... If it's more than 10 or 12 pounds negative at any point, then I probably need ditchable. Luckily, using my rig of an AL80 and a SS backplate, I've been able to never go over that personal limit.
But if I did, I'd simply use ditchable weight... Probably the SCB+ pockets, since I hate weight belts so much. They also allow me to ditch half my ditchable at a time.
I'm not "overweight", but I still have a (potential) problem!
Ah, okay, I see your point... I don't think we disagree on this topic, I think I just used somewhat misleading verbage when I described the situation.
We're in agreement, I believe.
I can't imagine a SINGLE tank configuration that gets me in trouble though. Let's say I have an HP120. Its got 9lbs of gas in it. With my "heavy wetsuit" exposure protection, which is a 3 mil full suit with a 3 mil hooded vest under it, I have compensation for about 15lbs of suit buoyancy; let's say half that gets lost at 100'. So I am now -16 at depth at the start of the dive. I know I can swim that up (I've tested it.)
Hm.
Firstly, it's my understanding that at 100', you lose much more than just 50% of your suit's inherent buoyancy... I understood it to be more like 85%... Which brings that number up some. And although I'm a very strong swimmer, I don't think I would want to swim up 16 pounds... Especially from 100', when my life depends on it. Are you sure you can swim up that much? Lastly, I believe that, if you look on my website under "Talk" and then "Equipment," you will find information regarding tank buoyancy... And you will find that LP steel tanks are even heavier than HP ones. Add to that a large capacity, full tank, and man, you're going to be swimming up a lot more than 16 pounds!
...And by the way, HP120's are not the most negatively buoyant tank made. In fact, they're probably the LEAST negatively buoyant HP steel tanks made, so we should probably use another example. Something tells me that we could easily find a combination that got you 30 pounds negative with a full tank, if we really tried.
I can also sit on the bottom and breathe some of the gas if I want, and THEN swim it up If I find this out at half-empty, I'll be -11-12ish, and that's not even difficult to swim up.
Like I said, I've never actually tried this exercise, but I don't think I'd want to attempt to swim up anything like that.
I can tell you that in my 3/2 mil, I'm positive by about 4 lbs, and that's a real pain when I do freediving without weight. I can't imagine three or four times that. I wouldn't want to do that...
