Kudos to the Ginnie Staff

[Spratman]

Wow!! I've read all the posts on here, and I think I'm in the Twilight Zone...

I'm just now reading Basic Cave Diving, A Blueprint for Survival. Sheck mentions in almost every case of a death that NSS investigated that it was lack of planning or diving beyond experience, or diving too deep.

I do a lot of research and reading before deciding on a class. I might be experienced enough next year to take the intro class. I'm not sure if I'll just take the cavern course, which is single tank, octo and flash light, or intro to cavern and cave with recommends single tank, h-valve, two 1st & 2nd stages OR doubles.

After 25 pages, I'm not sure of much except that it seems several certification agencies have allowed for people getting their feet wet with singles and/or doubles. There is another group about, raising a large concern that no one should be allowed to even get close to a cavern/cave, if they aren't diving full cave setup.

I'm confident in the instructor that teaches cave diving course, since she met up with her husband diving the Doria back in 72. If she says it's okay to try the intro class with singles, I believe her. Since the NACD and NSS-CDS says it's okay to take the intro classes with singles, I believe them as well.

No dog in the fight, just an observation and opinion. Oh yeah, I hope all the threads in this forum are not so stretched....

 

[WaterDawg]

a lp 121 filled to 3600psi holds 165cuft (121/2640 x 3600 = 165) 1/3 of that is 55cuft

a set of double 80's holds 155 cuft. 1/3 of that is 51cuft

so even if both dove to 1/3, the singles diver can make it farther into the cave, he also has less drag!

If at max penetration both have a failure:

1) the doubles diver (in this case) will be closer to the exit
2) he can isolate and save half his gas. While breathing down the free flowing side (if applicable)

Now if the doubles diver dove to 1/6 it wouldn’t even be close!


If limiting penetration is the idea, why not limit it by saying "intro divers can not penetrate beyond 1000ft" or something

Like Ive said before, I DO NOT think that if you dive a single into a cave your gonna die, just that for ME its not the preferred method. And that it shouldn’t be such a pain in the butt to actually dive that configuration (doubles) if one chooses to...And most here choose to.

single tanks are not more inherently
dangerous. end of story.

...which
means that if anything, doubles are more dangerous to intro divers than singles...

 

[GDI]

Ok well I have read all the threads that I had not read since my last read (if that makes sense?)

Someone, asked I think it was Notabob if I was on the BOD.
Yes I am, I am also the membership committee chairman and I sit on the training committee when needed.

Over a year ago when the NACD standards were being reviewed and updated I brought this issue forward at that time. Since this has come up with so much enthusiam between a couple of chat boards I thought I would address it again. As before I say that I can see both sides of this issue, I am not saying I support doubles or against doubles .
(I will ask why the signing of waivers is only available for full cave instructors as this is a good point)

I want to bring into light some other limitations regarding the Intro Diver.

ALL DIVES ARE PLANNED FOR THE EXIT NEVER THE PENETRATION

The Intro to Cave diver is not just limited by the single tank with H or Y valve, three lights a main reel and a safety reel. The Intro diver is also limited to doing a NDL dive.
Now bringing these factors together really does put the intro diver in a safe position on a single tank. The concerns of gas loss which are noted are not as big as many will think. Example is that a diver on a single 120 vs a diver on a single 80 both are limited to 1/3 gas supply. BUT since they must match cylinder volumes the diver with the 120 is also limited to 26.7 cu ft for their penetration same as their 80 cu ft buddy. At no point in the dive are you to be more then 1/3 gas and outside of NDL away from the exit . In fact the limit that you reach first (NDL turn time or gas) will be the cause to turn the dive. example at 100 feet you can only penetrate for 20-25 minutes subject to tables and computers being used. Further to the tank volume matching which cavern divers also must learn, the dive team is also to adjust their available gas supply to the SAC rates of the dive team members. The diver with the higher sac rate adjusts to the volume of the diver with the smaller tank and if that means not using a full 1/3 gas to penetrate then so be it because the diver with the smallest tank must be the controling factor of the dive and be able to get the diver with the highest SAC rate out of the cave. In short the dive is always planned to the weakest link and must be conservative to that respect.

Limits In review:

Single cylinder with H or Y valve dual regs one with long hose
three lights
primary reel
safety reel
dive made within NDL
cylinders matched for volume
SAC rates factored for

Considering these limits the Intro diver will not penetarte all that far. Failing to adhear to all the above mentioned limits the Intro diver is at a greater risk. At this level we are not just worried about cave conservation. We're are not just worried about the divers physical skill. We are but we are also aiming for the diver to further develop their awareness skills and dive planning abilities.

Many of the above arguements have focused on the gas supply and safety concerns. OK these are valid. But we need to address the other limts imposed on the intro diver to understand the entire picture. It seems to me that many of you were taught to focus mainly on the gas supply of 1/3's or 1/6's.

 

[wreckchick]

After reading this entire thread.... and being righteously amused at various points.... I can only offer the following:

It is a statistical fact that the murder rate increases in direct correlation with the increase in sales of ice cream.

There are more than a couple people out there that understand the significance of the previous statement.

Dive Safe!

Rachel

 

[H2Andy]

It is a statistical fact that the murder rate increases in direct correlation with the increase in sales of ice cream.

it is also a meaningless fact, as it assumes (or at best, implies)
a cause-effect relationship that simply isn't there.

on the other hand, it is a fact that of all the student intro divers who have
died diving in caves in the last 15-20 years, NOT ONE was wearing singles.

spin all you want

 

[mdb]

After reading this entire thread.... and being righteously amused at various points.... Rachel

agree, this is one sad thread. The same folks arguing back and forth.

 

[H2Andy]

jeez, don't read it. kind of sad wasting time reading a sad thread



or would you care to enlighten us all with your wisdom????

 

[wreckchick]

It's not spin. It's what every Intro Statistics student learns the first week of class. Correlation does not equal causation. There is very clearly a high degree of correlation between gear configuration and death in caves. In fact, this carries over not only from an Intro standpoint, but all the way through Full Cave. If the statistics from earlier are to be believed, and I see no reason not too, there has not been a case of ANYONE dying in a cave without wearing doubles. The same correlation exists there. In fact, if we look a little deeper, one could say that cave training is likely to get one killed in a cave. What are the proportion of trained vs. untrained divers that die in caves?

Just the world as I see it, Andy, take or leave it.

Rachel

 

[H2Andy]

ok, please answer me this question:

can you use existing evidence to support the following statement:

diving singles in overhead environment for new, introduction-level
cave divers is more dangerous than diving doubles?

 

[wreckchick]

Find out how many Intro divers that DIVING WITHIN Intro limits have died in the same time period. Only then is there even a remotely valid comparison.

R