The "other" end of the DIR question

[Boogie711]

I also do not want anything wrapped around my neck, ever! I can see that having the second bungeed under my chin, could be a good thing, and I also agree that a panicked diver might steal my primary...

Pasley - two points here.

A) The long hose does NOT - repeat NOT wrap around your neck. This is a common misconception about the Hogarthian dive style. At no point is the long hose an entanglement hazard.

...I have dove with several DIR divers. Some were good, others were overweighed accidents waiting to happen.

Then they weren't DIR. Period. They may have been diving in a Hogarthian rig, but as I've pointed out earlier, simply wearing a backplate/wings and a long hose no more makes someone DIR than wearing an Air2 and split fins makes them a PADI resort-course only rototiller.

 

[pipedope]

I don't see the bouyancy thing an issue of agency size so much as it is an issue of agency standards. GUE instructors are have a certain minimum requirements to that they meet or they will loose their instructor rating. Also, I don't think it's GUE's goal to be anywhere the size of PADI.


By the way, how have you been feeling lately; have you been diving much?

I first trained in OW and AOW with PADI in 1978 and 1981, the standards were high and the instruction excellent. There is a reason why both the standards and levels of instruction have changed. A lot of it has to do with survival as an agency.

I hope that GUE can both grow and maintain both their standards and high level of instructor performance. My point is that it is not easy to do so as you get bigger.



Unfortunately I am not diving now. I am hopeful that I will be able to do some easy beach dives soon, but I am not 'holding my breath'.
Right now, typing is about as hard of work that my hands will do.

 

[Dan Gibson]

Better check your dates. The term "Doing it Right" predates Halcyon and GUE.

http://www.pina3.net/dive/doitright.pdf
original article from DeepTech, Issue Number 3, 1995

There is no appearance, just laziness to get the facts before coming to such a conclusion.

I am also suspect of any system that gives the appearance, as IMHO DIR does of being built around a mfg product line.

 

[pipedope]

relatively high SAC rate, and it's safe for you to say that in an emergency their SAC could easily exceed 1 CF per minute? Really? Incredible!!

Hey, I can easily exceed 1CFm SAC even without an emergency. All it takes is a little work.

I think the spare air is a great unit. If I were riding helicopters to offshore rigs (especially over cold water) I would want one in my Mustang suit.
For diving I think there are better solutions, but I can see *some* situations were the spare air would be very useful even in diving.

 

[lamont]

I wrote up a quick perl script to play around with spare air calculations, and thought I'd share these two tables. The first is assuming a SAC rate of 1.5, no time on bottom, no stop and an ascent rate of 60ft/min. This is probably your average open water diver's response to an OOA, which increases DCS risk, but avoids drowining:

60 ft/min ascent with 1.5 SAC, no stop, and no time at depth
depth cuft
10 0.3
20 0.7
30 1.1
40 1.6
50 2.2
60 2.9
70 3.6
80 4.4
90 5.3
100 6.3
110 7.3
120 8.5
130 9.7
140 10.9

Here's the conservative side, with an ascent rate of 30 ft/min, a safety stop for 3 mins at 15 ft and 3 mins of bottom time to fix whatever problem is happening down there:

30 ft/min ascent with 1.5 SAC, stop at 15 ft for 3.0 min, and 3.0 min on bottom
depth cuft
10 13.0
20 15.1
30 17.3
40 19.7
50 22.3
60 25.0
70 27.8
80 30.8
90 34.0
100 37.3
110 40.7
120 44.3
130 48.1
140 52.0

Personally, if I ever think I need a spare air, I'll be diving with an AL40 slung as a stage or just use doubles. I can see, however, where a 13 cu ft spare air would keep someone from drowning in the case where the OOA is just caused by poor gas management and the OOA diver shoots to the surface.

[ I think 1.5 SAC is more reasonable than 1.0 in the general case, because I know that the first time I ever calculated my SAC it was 1.1 and that was without thinking I was about to die... If we're talking about handing off a spare air to a random OOA diver, you have to assume the worst... ]

 

[jhelmuth]

And the original question has faded into oblivion...

Just wanted to point out one little tiny problem with your calculation...you forgot to account for the fact that for every ATM, your actual gas consumption increases. Assuming your 1CFM SAC; 2CFM @ 33 feet, 3CFM at 66 feet and lo and behold...6CFM at 99 feet...hmm...don't think I'd try an ascent from 300' on a 13...I'd die...

:06: No. I stand by my calculations. SAC is (if properly calculated) Surface (IE - 1ATM) Air Consumption rate. IMHO a SAC of ~ 1.0 cf/min is not a bad approximation for a diver OOA with a normal SAC around .5 cf/min.

 

[dweeb]

I make alot of money from MSFT - go baby, go! Before you flame me, I will publicly state that yes, I am biased towards profit in my business... Whew - now I'm upfront, just like JJ...

Of course, the above (while basically true) is humor, before this spins off into meaningless drivel...

BTW, I did not accuse, nor infer, that there was a monopoly - only that there was bias - they are very different concepts that have nothing to do with one another.

As your first paragraph points out, a bias isn't a bad thing. The issue is simple. As head of GUE, JJ has a fiduciary duty, to see to it that GUE training is sound
and based on objective safety goals. As head of Halcyon, he also has a different fiduciary duty, so sell equipment. In order for this to be a problem, you have to show how any conflict of interest has caused him to violate one of these duties. Clearly, your IMPLIED thesis is that he might violate his duty to GUE students by swaying GUE/DIR gear recommendations to conform to Halcyon's offerings. However, no one, including you, has demonstrated that this has ever happened. In fact, what HAS happened is that he has guided Halcyon to make gear that conforms to GUE's recommendations. This in no way impacts his duties as head of GUE, and absolutely serves his duties as head of Halcyon. The influence all flows from the demand side to the supply side - GUE/DIR created demand, and Halcyon responded to that demand. The cart is behind the horse where it belongs, and all is well in the world. Ethics isn't about a weird feeling you have, it's an objectively ordered field, and no one's demonstrated where the problem lies.
The closest you can get to a problem here is that Halcyon might be privvy to 'insider' information on what changes may be imminent in GUE's recommendations, so they could be first to market with a conforming product. One small problem with that spin, though - when was the last time GUE made such a change in recommendation, i.e. where is the smoking gun? I think the success of Oxycheq's wings pretty much shows that no undue influence is working in Halcyon's favor.

 

[Boogie711]

:06: No. I stand by my calculations. SAC is (if properly calculated) Surface (IE - 1ATM) Air Consumption rate. IMHO a SAC of ~ 1.0 cf/min is not a bad approximation for a diver OOA with a normal SAC around .5 cf/min.

Helmuth, you're wrong buddy.

You wrote "13 cf / 1 cf/min = 13 min - 3 min safety = 10 min * 30 ft / min = 300' floor. Using a pesimistic view of having 2x the requirements for a greater margin of safety, that would make the floor 150'. (anyway, that's my thinking)".

Your math assumes that a SAC of 1cf is the same as 1cf at depth. Nope. You've ignored the pressure factor. A SAC of 1cf at surface means in that one minute, a diver would breath:

2cf in one minute at 33 feet, or,
3cf in one minute at 66 feet, or,
4cf in one minute at 99 feet, or,
5cf in one minute at 132 feet, or
6cf in one minute at 155 feet.

So, with a 13 cf bottle at 150 feet, assuming no time needed to fix anything, at a 33fpm ascent rate, you would burn 5 cf in the first minute. 4 in the second minute, and uh oh - you're out of air at about, oh - 66 feet.

A 3.0 spare air is even more ridiculous. Hand it off at 100 feet to a diver, and he bolts to the surface at 60 fpm, and he still runs out of air with about 30 feet to go.

 

[jhelmuth]

I wrote up a quick perl script to play around with spare air calculations...
...
...
I can see, however, where a 13 cu ft spare air would keep someone from drowning in the case where the OOA is just caused by poor gas management and the OOA diver shoots to the surface.

[ I think 1.5 SAC is more reasonable than 1.0 in the general case, because I know that the first time I ever calculated my SAC it was 1.1 and that was without thinking I was about to die... If we're talking about handing off a spare air to a random OOA diver, you have to assume the worst... ]

Nice job with the pearl script. I would note that my assumption of ~1.0 cf/min SAC is just that - an assumption. I use my own experience as my guide, but do not recommend that others rely on that. I derive that the same divers "normal" SAC is ~ 0.5 cf/min. I would also add a margin of safety to the supply so that the diver does not necessarily "run out" at the surface. That is why, for me anyway, I'd apply the 2x rule. The 13 cf pony is/would be my choice because it calculates to a floor of 150 fsw (for me), which is slightly beyond my personal limits.

 

[Boogie711]

The 13 cf pony is/would be my choice because it calculates to a floor of 150 fsw (for me), which is slightly beyond my personal limits.

Jhelmuth - read the post above yours.