halcyon eclipse for doubles?

[MXGratefulDiver]

Hey Tobin,

I feel we may have to stop the debate. From the GUE DIR camp there is no acceptable method to dive double steel while wet. Single steel "maybe". Well in a 7mm semi dry I'm quite happy to dive a single 130....

The overall concept of the GUE DIR point of view on this is sound, good advice. But like every rule there are exceptions. Thing is that exceptions are frowned upon to ardent followers so thus are dismissed out of hand. I personally chalk this up to lack of experience.

There should be no "debate" about it.

Whatever you chalk it up to, the question was asked in the DIR forum ... which mandates a DIR response.

From the sticky that explains the rules for posting in this forum ...

6) The answers in this forum are member's best attempts to answer questions within, and according the DIR diving philosophy. If you wish to give a non-DIR answer, please do not post it in this forum. If you do not wish your question to be limited to DIR answer, please ask it in another applicable forum.

Non-DIR solutions should not be posted here. If the OP had wanted a non-DIR solution, he or she would have posted the question elsewhere.

... Bob (Grateful Diver)

 

[globaldiver]

Regarding what Halcyon wing to use:

I use the Evolve 40lbs with dual PST E-7 100s, and dual aluminum 80cf tanks. I also carry one 40 cf decobottle. This setup works very well.

I use the Evolve 60lbs wing when diving dual PST E-8 130s/104 tanks. Previously I used the Explorer 55lbs wing but have switched to Evolve wings since I like them better.

Anders

 

[cerich]

There should be no "debate" about it.

Whatever you chalk it up to, the question was asked in the DIR forum ... which mandates a DIR response.

From the sticky that explains the rules for posting in this forum ...


Non-DIR solutions should not be posted in the DIR forum. If the OP had wanted a non-DIR solution, he or she would have posted the question elsewhere.

... Bob (Grateful Diver)

NO Bob, there should be. You are mixing up GUE and DIR.
DIR is "DOING IT RIGHT" it is NOT GUE. GUE was and is instrumental in making DIR available to the masses but has no lock on DIR (they did try however ) GUE teaches the "No steel when wet" rule of thumb (as does NAUI Tech BTW)

What is DIR in regards to the question? Working from the goal of being in a balanced rig regardless of what the individual is diving as DIR, the quest then becomes what will work to achieve this. Simply saying that all steel cylinders are not DIR when wet excludes thought. Thinking divers is also a DIR principle.

In the example I gave you can achieve a balanced rig with steels in doubles (again most steels I would NOT recommend doubles and wet). Now prove given that the DIR goals are met that this is indeed not DIR, do so without fallling back on boiler plate if you please.

Best,

Chris

 

[DIR-Atlanta]

A luxfer cylinder (standard 80) goes from -1.4 full to +3.4 with 500 psi. So in doubles -2.8 full and +6.8 at 500 psi (not including bands, manifold) (You had this correct)

Not to quibble, but the definition of "buoyancy swing" is from full to empty, not full to 500 PSI (unless you know a way to keep the last 500 PSI from escaping during a catastrophic valve failure). The worst cases from a buoyancy standpoint are "full tanks, max depth" and "empty tanks, shallowest stop". FYI, I pulled the buoyancy numbers directly from the Luxfer website, so I am not suprised that they are correct.

The cool aide is sweet but the mind is sweeter....

Believe me, I have thought about this kind of stuff a lot over the last 10-15 years (and wasted a lot of money on poor decisions and bad gear choices). What I have found is that the longer I dive, and the more thought I put into my diving and what makes the most sense both logically and logistically, the more sense it makes to stick with DIR.

I know this goes againts the mantra that you suscribe to, but if you get a chance dive some doubled 85's wet, you may find yourself thinking they are the better way to go.

Thanks, but no thanks - my comment about "orphan tanks" was from the school of Been There, Done That. I already have enough unsuitable tanks in my garage to last me a while.

 

[cool_hardware52]

There should be no "debate" about it.

Whatever you chalk it up to, the question was asked in the DIR forum ... which mandates a DIR response.

From the sticky that explains the rules for posting in this forum ...


Non-DIR solutions should not be posted here. If the OP had wanted a non-DIR solution, he or she would have posted the question elsewhere.

... Bob (Grateful Diver)

Bob,

This no troll, it's a genuine attempt to understand and stay within the rules.

What I see is a conflict between two GUE guidelines, i.e. the concept of a ballanced rig, and the second being "no steel doubles with a wetsuit"

If you meet the first criteria does the second still apply?

Is the orignial intent of these guidelines unworthy of debate?

I suspect, and may well be wrong in this specific case, that like many other GUE guidelines, the original "no steel doubles with a wetsuit" was based facts that have changed. Consider PST 104's and their popularity in cave diving, these tanks are negative even when empty, clearly a bad idea when diving wet.

Bolt snaps on lightheads, finger tight second stages, cuff dumps, scooter ring placement, etc. All debated, all changed.

Your thoughts?



Tobin

 

[cerich]

Thanks, but no thanks - my comment about "orphan tanks" was from the school of Been There, Done That. I already have enough unsuitable tanks in my garage to last me a while.

I wasn't suggesting you buy them, just try them!

I have a bunch of useless tanks as well!

 

[cerich]

Bob,

This no troll, it's a genuine attempt to understand and stay within the rules.

What I see is a conflict between two GUE guidelines, i.e. the concept of a ballanced rig, and the second being "no steel doubles with a wetsuit"

If you meet the first criteria does the second still apply?

Is the orignial intent of these guidelines unworthy of debate?

I suspect, and may well be wrong in this specific case, that like many other GUE guidelines, the original "no steel doubles with a wetsuit" was based facts that have changed. Consider PST 104's and their popularity in cave diving, these tanks are negative even when empty, clearly a bad idea when diving wet.

Bolt snaps on lightheads, finger tight second stages, cuff dumps, scooter ring placement, etc. All debated, all changed.

Your thoughts?



Tobin

Hey Tobin,

Only AG started the cuff dumps on the drysuit, that never was DIR.....

It's a little like trying to argue a Halcyon SS inflator is DIR, it has to be right? Except it needs so much attention to be reliable(if ever) that it isn't Doing It Right at all.

 

[DIR-Atlanta]

Where did I say I'd ever be at 165 on a single LP85 on air?

You didn't - where did I say that I thought you would be?

Seriously though, I know of people who would use air or a light Nitrox at that depth. I wasn't making assumptions about what you would do, and I apologize if it seemed like I was. I was merely explaining what my personal standards would be for doing that dive. What I was trying to emphasize is that it would be a "mandatory" deco dive for me (based on my choice of gas), so I would obviously prefer doubles for that - if I were diving wet, then that would be double AL80s.

I mentioned 165 only to point out that above that depth neoprene is still somewhat buoyant.

Not enough for me.

I know you can "do the math" so it seems silly to mention this, but 165 feet is 6 ATA, so your 3 mm wetsuit will only be 0.5 mm thick. Even a 7 mm wetsuit wouldn't be much more than 1 mm thick at that depth. That's insufficient buoyancy IMO, and then there is the thermal issue as well. I just don't see how that is more desirable.

 

[cool_hardware52]

I know you can "do the math" so it seems silly to mention this, but 165 feet is 6 ATA, so your 3 mm wetsuit will only be 0.5 mm thick. Even a 7 mm wetsuit wouldn't be much more than 1 mm thick at that depth. That's insufficient buoyancy IMO, and then there is the thermal issue as well. I just don't see how that is more desirable.

Minor point: Neoprene is not all compressible gas, it's a closed cell foam, some of it's volume is compressible, and some is not. As a consequence it does not compress in a linear fashion with respect to ambient pressure.

I'll easily conceed that neo at 6 ATA is not the best solution, from either a buoyancy or thermal protection standpoint, but I was not suggesting it was.

I was discussing the merits and risks of using lightweight steel doubles with a wetsuit. When calculating the maximum weight one might have to swim up in the event of total buoyancy failure how neoprene behaves is worth considering.

If you are in lightweight steel doubles and have a hard bottom at 120 fsw your suit will still be somewhat positive, reducing the "swim up weight"

I prefer to dive doubles, and often make 2 decent rec dives using them. Often no deeper than 90-100 ft, sometimes shallower. Is my rig unbalanced in these conditions?


Tobin