Personally..I'd pull water into my mouth, swish it around real hard then blow the hydrogen into the wing and the O2 out into the water. You must be careful not to swallow any of the pure O2 at depth.
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Personally..I'd pull water into my mouth, swish it around real hard then blow the hydrogen into the wing and the O2 out into the water. You must be careful not to swallow any of the pure O2 at depth.
"..., some rigs can't be balanced. (or its impractical to do so) So you need to decide if you want to do the dive (or not)."
I'm assuming that what you mean by this statement is that your 'rig in salt water filled with helium mix was very balanced' without any stage bottles or deco bottles, right?"...My dives with double 130's, Nitrox and in fresh water was very "unbalanced". I did the dive anyways, because if my BCD bladder failed, I would just walk on the bottom of the lake until I got out.
In salt water, with a helium mix. The same rig was very balanced.
"..., some rigs can't be balanced. (or its impractical to do so) So you need to decide if you want to do the dive (or not)."
That's the definition. But adding the other stuff is really insignificant. You are talking about an extra 3-4 lbs. Physics is a stubborn thing.I'm assuming that what you mean by this statement is that your 'rig in salt water filled with helium mix was very balanced' without any stage bottles or deco bottles, right?
Has nothing to do with the current conversation.I'm aware that scooters are neutrally bouyant, but they have mass
on the internet I guess. LOL- resistance that adds drag, increasing the amount of effort needed to push them through the water.
Why do you keep bringing up the scooter?????? ITS NEUTRAL!!!!!!Had I ditched all my sling tanks and scooter its possible that I may have been able to swim the backgas up, but there are still physiological issues with CO2 loading at work.
No, you said its a myth.I'm not against being able to swim to the surface if you have issues, but I disagree with the dogma that suggests that a 'balanced rig' is universally an optimal solution.
I don't think you understand it.Beyond a certain level of diving, I don't find that a compelling argument. Taking into consideration issues of CO2 loading; and the costs of jettisoning tanks, gas, and scooters (both in terms of money and in terms of resources you could use on the way up); my argument is that there's a better way to plan deep dive problem-solving than ditching your can light and sling tanks and swimming up. But thats just me. If it works for you, great.
LOLWhere we agree is here:
If you decide you want to do the dive, then you also need to figure out how you're going to respond safely to issues that may occur during those dives where "some rigs can't be balanced".
It fascinates me how this thread has morphed from a question that arose from a recreational, single tank dive, into what one does with scooters and multiple deco bottles.
My setup is close to yours.In using the example of a 220' dive in salt water I am starting with a fully kitted out tech diver with double steel 130's, an AL 80 bottom stage, one Al 80 of 50% (or Al 40 depending on run time) and one Al 40 of 100%. This diver has a scooter and no camera. This diver is diving 15/55 trimix and wearing a 400 gm thinsulate undergarment and a tri lam drysuit. He is also carrying a typical 21 watt HID light. Since our gang regularly dives in this kind of environment I am using my weighting as a starting point.
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I use a 5.5 kg backplate
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So I open to floor for comments. Jeff, I get the impression that you have some different views here and I welcome your input.
Totally agree with thisFurther, you have various tools at your disposal to help you deal with failures, but I believe we have to be realistic about the number of failures we plan for: buddy seperation? I am outta here. Wing failure? I am on my way home with or without some of my gear. Drysuit failure? Same thing. All these things happening at the same time? The sport has inherent risks. Period. But in my view, when the perfect storm comes along, it comes along. It is a question of how likely this could come along. I plan for one major failure and shut things down. Three or four in one dive? Somebody really doesn't like me and I am probably screwed. But I don't get out of bed each morning worrying about getting in a car crash and then getting hit by a passing car as I extricate myself from my broken vehicle, while I am also getting struck by lightning.
This tooYou also have the chance to just not do this type of dive. This is just a sport and nothing in the ocean is worth dying for so maybe the risks in this diveplan risks are unacceptable to many people. I think it also points out several very serious considerations: Doing this type of diving with a team that is not switched on is a very bad idea. A well practiced team is less likely to get seperated, can help with moving gear around, can take extra gear and manage a bad situation in a far less "dramatic" fashion than a bunch of dudes who are on the "same day-same ocean" program. Moreover, this diving requires some significant training. Maintaining your poise and keeping your wits about you when the **** hits the fan requires skill, training, and constant practise. Simply thinking through this problem while at depth and facing possible catastrophic consequences will use up a lot, if not most, of your available bandwidth. You don't have a lot of left over brain cells to deal with buoyancy issues, etc. This stuff has to be ingrained in your subconcious.