roll on roll off

[ltb7733]

i went to beneath the sea in new jersey and had a blast. if you havent gone, try to make it at least once. anyway, i picked up a copy of IMMERSED, FALL 2003 and there was an article by jeffery bozanic on manifolds. I used to dive in new york in the early 90s with independent doubles. got strange looks from my fellow divers. like any other rig, it has its pros and cons. ( i didnt know it at the time, but i was practicing for side mount training by switching regs. some day i will get there) anyway, i was shocked to read that a whole artilcle was devoted to roll off problems. i thought that if you were having roll off problems i assumed:
1. you dont have your trim worked out

2. you are in a place too tight for a backmount rig and need to be in sidemount rig.

roll off problems tell me that the caves are getting damaged. Is this a real problem that we dont want to talk about, or its not really happening that often? then why a whole article on it? So i ask the cave divers whats the real story? thanks ltb7733

[curtschu]

Look at the IRAP and you tell me. There are a bunch in there about roll offs
Just about every cave has at least one spot that is "a little tight" This seems to be where roll offs occur. I don't think people are banging along the ceiling if so you’re right they got issues. This is why I think if someone came up with a positive but simply disengaged lock on the valve you might have a winner. There was a guy that posted about a design exercise he was conducting to address this among other valve related issues. He was thinking of a guard but I think that was the wrong course as he soon found out from the types pf replies he got. It also could be addressed with the position of the valve handles, how about pointing down at an angle say 30 deg. and forward at 5 deg the manifold would look kinda like a droopy dog’s ears this would change the angle that the handle hit and still allow easy access. Manufacturing might be the problem here.

Anyway that’s my two cents

[Sid]

Well I can't resist. Pretty much you can roll off the left post moving forward easily, especially if you got the soft rubber knobs, the right post will just get jammed on tighter if you hit moving forward. Not a problem if you can reach your valves, everytime you get near the ceiling or go through a restriction just check your valves and make sure they are open. If your hitting hard enough to bend stems (like a good wack when scootering) you need to develop better skills (don't know anyone who ever done this but...:)snicker). Also you can get really strange rolloffs rubbing alongside anchor lines in choppy water. Worst thing that happens is you suddenly got no gas, but it should be second nature which way to turn a valve back on if you practice and aren't too dislexic(sp?) BTW if you are moving at mach 2 or so exiting through the lips, etc at devils or someplace that low, might want to wait a couple of seconds before wedging you hand inbetween the valve and the ceiling and grinding off a finger, cave diver conservatism sort of.


Ahh that feels better. Sid

[Gary]

roll off problems tell me that the caves are getting damaged.
I would say that most roll offs are an indication that people are contacting the ceiling WAY too much and should be fixing something in what they are doing.

[jammer]

Well I have to say I was trained to check my air offten and everytime I check my air to check for roll off so it keeps you safe no problem it is now something I do without thinking twice about it. I know they make these neat little stainless knobs I have seen them on some rental tanks at the Dive Outpost.

[ARY]

Well I can't resist. Pretty much you can roll off the left post moving forward easily, especially if you got the soft rubber knobs, the right post will just get jammed on tighter if you hit moving forward. Not a problem if you can reach your valves, everytime you get near the ceiling or go through a restriction just check your valves and make sure they are open.
Agree. It is easy to detect roll off if you have inflator and SPG on left post: you suddenly loose air or find yourself face in clay which simply indicates recent roll-off (or true OOA :-) ) Sidemounted tank also doesn't guarantee that you never shred stem. I had cylinder fallen into hole from my hands while i was pushing it through restriction, result-sliced knob (in opened position). Impact was very very little and apparently enough to cause a damage. After that i would rather hit ceiling with my head then touch it with valves.

[NitroxWarrior]

I've always been much more afraid of damaging the valve then having rolloff. I only use a guard because the thought of experiencing some sort of extreme loss of boyancy control(Such as drysuit over inflating) hit my valves on the ceiling and having a valve bust.

[John L.]

Welcome back Sid! Good to see you posting again.
John

[Stu]

I reckon there's another way to avoid this - at least to a large extent.

Mount your tanks inverted. I discussed this during my full cave class and got told the dreaded words "Bad student! Entanglement risk!" but the more I think about it, the more sensible it seems. ("Bad qualified diver!")

AFAIC, you're more likely to run into line which is drifting above your head. You drift into this valves first, then you've got all those strangely shaped bits of metal and rubber to get entangled as opposed to the rounded ends of a couple of tanks. Same with a roll-off. You're more likely to figure out that you want to be a little bit further from the ceiling when the part of the tank nearest the ceiling impacts, and that's generally going to be the bit above your shoulders. With tanks mounted "the right way up", you're going to start to roll off on that impact. With tanks inverted, you hit a big, round piece of metal that gently smooths away the ceiling above rather than digging strangely shaped holes in it.

For those of us like me who have enough trouble scratching our heads never mind reaching valves, mounting tanks inverted also makes a huge amount of sense. Now the valves are almost level with my arse, and while I may have wiping problems (seriously - what idiot thought white underwear was a good idea? :evil: ) at least I can reach around there to scratch. This means I can reach all the valves easily, and if anything there does get entangled, I can reach it without having to undo my crotch strap and waistband (usual method of reaching my valves) and work it out in comfort.

Another point with this - the fact that you're mounting your tanks upside down generally means that you'll need some sort of guard rail to sit them on. This should also help avoid roll-offs ever occurring, and though ("Bad diver!") it may be an entanglement risk, I don't see it as any more of a problem than the valves themselves.

[Sid]

I reckon there's another way to avoid this - at least to a large extent.

Mount your tanks inverted. I discussed this during my full cave class and got told the dreaded words "Bad student! Entanglement risk!" but the more I think about it, the more sensible it seems. ("Bad qualified diver!")

AFAIC, you're more likely to run into line which is drifting above your head. You drift into this valves first, then you've got all those strangely shaped bits of metal and rubber to get entangled as opposed to the rounded ends of a couple of tanks. Same with a roll-off. You're more likely to figure out that you want to be a little bit further from the ceiling when the part of the tank nearest the ceiling impacts, and that's generally going to be the bit above your shoulders. With tanks mounted "the right way up", you're going to start to roll off on that impact. With tanks inverted, you hit a big, round piece of metal that gently smooths away the ceiling above rather than digging strangely shaped holes in it.

For those of us like me who have enough trouble scratching our heads never mind reaching valves, mounting tanks inverted also makes a huge amount of sense. Now the valves are almost level with my arse, and while I may have wiping problems (seriously - what idiot thought white underwear was a good idea? :evil: ) at least I can reach around there to scratch. This means I can reach all the valves easily, and if anything there does get entangled, I can reach it without having to undo my crotch strap and waistband (usual method of reaching my valves) and work it out in comfort.

Another point with this - the fact that you're mounting your tanks upside down generally means that you'll need some sort of guard rail to sit them on. This should also help avoid roll-offs ever occurring, and though ("Bad diver!") it may be an entanglement risk, I don't see it as any more of a problem than the valves themselves.

You got to be kidding, right? So now to avoid a problem that doesn't exist, you got your valves and 1st stages getting smashed everytime you hall yourself out of a cave, do the death march and hit the picnic table or tail gate of the truck. As for entanglement, your not supposed to swimming under lines getting your manifold wrapped up, and if it's really low and the lines are all stuck in the ceiling, well don't go there if you can't help but get tangled. Much simler and elegant to just learn how to turn valves on and off. BTW I like dark red silk underware for several reasons (1) it feels gooooood (2) when you run into Gary solo diving with his independent transverse mounted tanks and you do get startled the stains are easier to hide/spotclean (3) silk will wick the sweat accumulated from the deathmarch away from the sweetspots into the drysuit underware. Ok I'm going to work on my dorsel mount rig now. Sid

[divindoubles]

IMHO, the entanglement risk would far outweigh any reduction in the risk of a rolloff. Rarely, if ever, do you read an incident report involving a fatality from a rolloff. Rather, rolloff incidents usually wind up making excellent dive shop or bar tales. Entanglements, on the other hand, have been responsible for many fatalities over the years. Having experienced a rolloff myself, I can say that it is a minor inconvenience (and in my case was very preventable, skills-skills-skills) but was easily corrected. When I tried to inflate my wing, it let me know immediately what the problem was, and when I finished correcting the problem, I marvelled that it had happened to me. (Cool, I had a rolloff! I think were my exact sentiments.)
Anyhow, that's my 2cents worth. And remember when you pee that your buddy may be closer than you think!

[NitroxWarrior]

just be frikin' carfull when diving!
do not hit the ceiling!
stay out of your guide line!
and
do not try some weird setup until it is more widly accepted!

you dont have to sit here and try to figure out how to fix problems that are not really a real problem.

heres a real problem! keeping idiots from going into caves without training, that is still a risk. I'm not saying to close any caves but something needs to be done.
think of all the people that pulled up next to little river and just decided to check it out, think of all the dive instructors that have done this and never come out.

sry, just had to let that out... lol

[rchrds]

Mount your tanks inverted.

AFAIC, you're more likely to run into line which is drifting above your head. You drift into this valves first, then you've got all those strangely shaped bits of metal and rubber to get entangled as opposed to the rounded ends of a couple of tanks.

Gotta try everything once. Mount your tanks inverted. Move your bands so that you get neutral longitudinal bouyancy. (front to back even.) If you're diving 120's odds are you wont be able to reach your valves. Even in 95's you cant reach the isolator.
Now get a buddy to make a loop of line and make one turn around the isolator or the body of the first stage.
Now hold that line directly away from your butt- as if you were swimming from the line cause you couldt immediately figure out what you were wrapped on. Can you even reach both ends of the line to cut it?
Nope.
Odds are you wont be able to tell which side is which- as you reach around your butt to cut the line. Say goodby to your downstream line the high flow crappy viz.
Hope there arent any side passages as you feel your way out of (or into) the cave.

Enough?

J

[rchrds]

Oh yeah- if you are wrapping the line in your valves now- you sure as hell will be when turn around in a narrow passage.

Sorry- this is in addition to the "cobra gaurd" argument- which implies as someone else mentioned, that you would have to add something to protect your valves when you set your tanks down.

Unless he/she is a hero- and takes their tanks off over their shoulders without a bench-- ha. tried that once. Dont do it. urg...

J

[rchrds]

do not try some weird setup until it is more widly accepted!


Wow- since I'm short on sleep- and my rant button appears to be stuck- Ill let go on this one....

Try it. Try everything you ever could think of. But try it with friends in normal rigs, who are anticipating problems. and in very familiar places.

If someone didnt experiment, we wouldnt be cave diving. Or sidemounting. Or gas diving. Or going into space. okay- we get the picture.

Or I suppose you could just wait until someone makes a C-card and then pay for it.
:roll:



heres a real problem! keeping idiots from going into caves without training, that is still a risk. I'm not saying to close any caves but something needs to be done.

Wow. I'm not sure why this is really bending me out of shape today. Again must be lack of sleep. You are right. Something needs to be done. So step off the pedestal. When you see someone untrained who is obviously going to go into the cave- cancel your dive. Offer to go with them. Offer to teach them the basics of line navigation, and then when they are all finished with their little dive, demonstrate how dangerous things could be with a little siltout demonstration, and then point them to an instructor you might know- or take them under your wing.

It is this condescending attitude that is killing recreational cave diving. You dont have to be an instructor to teach someone to cave dive. Only to give them a C-card. If you are not competent enough to teach the skills you know, shame on your instructor. Go get your money back. The CDS and NACD have been kind enough to provide an outline for safe cave diving instruction. Hopefully, you filled in the knowledge over the extensive amount of diving in numerous systems you caved in during class. You should know that information inside and out. Your technique in backmounts should be impeccable. If it is not- you were not ready for your C-card and your instructor is responsible for this failure. But odds are he/she just wanted your money.
One organization has apprentice for a reason. You are an apprentice cave diver during your full cave course. You are learning. Only when you are TRAINED should you be getting a C-Card. People dont get TRAINED in two weekends. And a person certainly doesnt get a feel for his or her limits in two weekends. That takes months of diving continuously.
Yes- a C-Card is a licence to learn- things that werent in the curriculum. If you are still "honing" your skills on your graduation dives your instructor should be fired.

Caving for Pay folks: Bring it.

:smt027

[Stu]

[puts up heatshield]

So far, I've never had a roll off, and never had an entanglement involving my tanks (fins, backup lights, computer, but not the tanks). But it's been my experience that I've never hit the bottom of my tanks on the roof while diving, and as such a roll off is even less likely there than it would be with the valves at the top.

The kind of valve protectors that I talked about in my original post are more likely to allow any line to drift over the valves instead of helping entangle them. Again, given that it tends to be the front of tanks (ie, the valves when you have that perfect longitudinal buoyancy) that get hit more often when cave diving, I'd say it's the point which is most likely to get an entanglement anyway, so having something smooth there, such as the "round ends" of the tanks (can't call them the bottom in this configuration) means you should easily be able to back out of the line without getting entangled.

Purely for an example picture, and with no endorsement of the product, here's a link to the kind of protector I'm talking about: http://customdivers.com/valveprotectors.htm. I reckon this would *entirely* protect you from roll offs unless you're doing something very silly, or have a very bored buddy behind you.

The only additional entanglement risk that I see from this is where you back into a line which ends up getting between your body and the valve protectors. I figure there's a way to get around that by putting a couple of bits of velcro between the back of your wing and the inside of that guard - a line would have to be incredibly slack to get inside the hoop of the guard and wrap itself around one of the knobs. I'd have to disagree on the ability to reach the valves in this config, since it's the way the British Royal Navy divers dived for years. No pressure guages, you just isolate the tanks, breathe off the first until you have to start sucking, reach back, open and close the isolator. Breathe until you start sucking, open the isolator, then ascend knowing you've still got 1/4 of your starting gas. Doesn't sound like too much of a problem trying to reach the valves. Maybe they just used a pile of ankle weights so they could mount the tanks higher. Or maybe Johnny just has short arms :P

Don't try a wierd setup until it's more widely accepted?!? Why use a wheel when feet work so well? How's it ever going to become widely accepted until someone tries it and finds that it really works? Some people appear to think there is only one way to dive, and do it retentively. They believe that equipment configurations should never vary from that setup. This may mean that a diver cannot pass a restriction which is smaller than the size of the diver with, for example, a backmounted twinset. While exploration by humans will always be limited by the size of the person exploring, we don't need to be limited by convention. That way lies stagnation.

As for the underwear thing, I found silk too expensive. Tried sheer nylon, but the static kept lighting my farts. It was great for improving my cycling speeds, but a prohibition order being put in place by the local hospital's burns unit meant I had to stop using them after a fire in a local nightclub. Words from the wise: don't go table dancing in nylon underwear when people are drinking spirits. :!: They have to be hammered to let me table dance though....

[Stu]

Guess we were composing those at the same time. Loved that third post, Johnny - especially as it's the first follow-up that didn't conflict with mine :) Sadly, I'd never really considered taking an untrained diver into a cave - you see how much these instructors damage us? Just look at the *fun* we could have!

Stu da Sade. :twisted:

[rchrds]

Guess we were composing those at the same time. Loved that third post, Johnny -

hehe- I'm not Johhny- he's just unfortunate enough to have my last name- or is it the other way around- He's gonna hate me if he doesnt already.

The other J
:twisted:

[Stu]

Maybe *you* have short arms then :p

[NitroxWarrior]

sry for getting all pissed off about this, but its my opinion that trying somthing in an unforgiving environment such as an underwater cave is stupid, experimenting is great as long as your smart about it.

Shek did a ton of testing on his dive rig before going for the thousand foot mark and he still didn't make it back to the surface alive.

[Gary]

Shek did a ton of testing on his dive rig before going for the thousand foot mark and he still didn't make it back to the surface alive.
Sheck's safety margin on that dive was measured in breaths (aproximately 3 I think - much less then 5 minutes of reserve gas). We also recently had a couple divers at Eagle's Nest find that a 10 minute saftey margin for availible gas was't really enough to deal with a problem and make it out.

When a third of you gas is only a few minutes then is isn't really enough time/gas to deal with a problem. If any gear failure on your dive is going to take more time to deal with then you have gas reserves available then there isn't enough saftey reserve.

That Sheck lost his life simply mistiming his breathing technique is a clear indication that he was not prepared to a reasonable extent for the various failure posibilites on his dive.

It really had very little to do with how much testing he performed on his rig.

[rchrds]

sry for getting all pissed off about this, but its my opinion that trying somthing in an unforgiving environment such as an underwater cave is stupid, experimenting is great as long as your smart about it.

Shek did a ton of testing on his dive rig before going for the thousand foot mark and he still didn't make it back to the surface alive.

Oh- its nothing personal certainly. Just some of us have a different view of the environment. I almost never open water dive. I would rather test a brand new piece of obscenely new gear in the first room of a clear, medium flow cave with gravel bottom than take it in open water. I dont consider a cave to be an unforgiving environment. And I dont consider open water with unpredictable flow, bottom conditions, creatures, visibility and temperature to be an advantage. My "escape to the surface" impulse has either been completely supressed, or I never had one. Case in point- a three way airshare, necessitated by a blown gauge in zero viz halocline conditions: All three of us escaped INTO the cave, despite a both bottles off restriction- where the water was clear. We sorted things out and continued the dive. Going to the surface was never considered. So I guess it all comes down to training.

And I dont think that your implication that Exley was stupid is valid at all. The cave was not the factor that contributed to his death. It was depth. He knew and accepted the risks. He trained with all of his new gear, of which there wasnt much, in my understanding (in caves, by the way) and he in the end felt the risk level was acceptable. Perhaps it was. I'm quite sure nobody knows exactly what went wrong, nor would I like to speculate.

But please refrain from imparting your rote memorization of the training handbooks in such a manner as to imply that nobody should try anything new in a cave. I will concede, that there are some things better left for the basin- i.e. your first few breather runs- (though even mine were in a cavern zone).

In the example (reversed tanks, if anyone had forgotten) we have been talking about- should I ever decide that I wanted to try this (which I wouldnt, BTW) I imagine that my progression would be throw the junk on in the basin of my local large cave (JB, in my case) with two buddies, and adjust until I was neutral- while they check for problems. Then we'd be headed for the first room and cavern zones for the test dive. Both buddies with me are watching (and expecting) me to have problems. If we dont, cool, end the dive and get on with it. At least I know if things go all bad- I wont pop to the surface- I'll just stick to the ceiling, and we can deal with things there.

Again- nothing personal, just consider that not everyone may be at your level of training. Nor mine.

J

[Cindy]

Hey J, Forrest used to wear his tanks upside down with guards. I think he would still be doing it if it worked. What is the deal lately, everyone keeps re-inventing stuff that's already been tried. It looks like a potential cluster to me. I like all my toys right where I can reach them and see them.
Your method of trying stuff out in the basin is pretty much what I do. Testing the rebreather in the pool at my place didn't work as well as under real conditions. I did of course have VERY skilled buddys there for both events. Speaking of rebreathers, how is the side mount mouth piece coming along? Cindy Butler

[curtschu]

It is human nature to try and be innovative and we are technical people by definition. The problem is that people have been Cave diving almost as long as there has been scuba, so it is seldom that something truly new will come long. Heck Trimix is nothing new Commercial guys have been using it for years, Rebreathers are certainly not new. Dragers have been around since what 1942? What is new is the access to the specialized training needed to take advantage of these technologies, and since more people are using the stuff it means the manufactures are motivated to innovate (there's that word again) We will always try to think of new ways to pursue our sport. We all need to not be Critical of folks that might not have been around since the 80's when most of the big improvements in equipment and technique were made.

[normblitch]

sry for getting all pissed off about this, but its my opinion that trying somthing in an unforgiving environment such as an underwater cave is stupid, experimenting is great as long as your smart about it.

Shek did a ton of testing on his dive rig before going for the thousand foot mark and he still didn't make it back to the surface alive.

And I dont think that your implication that Exley was stupid is valid at all. The cave was not the factor that contributed to his death. It was depth. He knew and accepted the risks. He trained with all of his new gear, of which there wasnt much, in my understanding (in caves, by the way) and he in the end felt the risk level was acceptable. Perhaps it was. I'm quite sure nobody knows exactly what went wrong, nor would I like to speculate.



J

IMHO, anyone who considers Sheck stupid or careless, was never his Friend or Student, and CERTAINLY never dove with him...

I was blessed with all three...

Norm

[Gary]

IMHO, anyone who considers Sheck stupid or careless, was never his Friend or Student, and CERTAINLY never dove with him...
I don't think NitroxWarrior meant to imply that at all (I think he was using him as the very example of extreme caution and attention to detail). My own example did kind of accuse Sheck of a certain kind of incaution (intentionally entering into a situation that overbalanced his margin for error) - but I think he did it with full knowledge and acceptance of the risks it entailed. I would have been proud to have have been his student, friend or dive buddy - unfortunately, he died shortly before I would have got my chance to meet him.

[ltb7733]

thanks for all the replys but we are getting off the main topic (heavens to mergatroid even) it takes about 5 to 6 full turns to close a valve, that means about 15 to 20 hits (at a quater turn per hit) on the ceiling to close off. thats completely, or should be, unacceptable to the cave community if we are for preservation. one or two hits per dive adds up to a lot of damage. a complete roll off in one dive tells me i dont deserve to be in a cave. thanks for contunuing this thread. ltb7733

[NitroxWarrior]

whoa whao whoa! I am NOT saying shek was stupid, I thought he was a really great guy and an incredible diver that was more than capable. I'm just saying that no matter how well everything is tested you can still have a problem that will cause you your life, I guess I was contradicting my statment about testing but :? you know how that goes...

[NitroxWarrior]

IMHO, anyone who considers Sheck stupid or careless, was never his Friend or Student, and CERTAINLY never dove with him...
I don't think NitroxWarrior meant to imply that at all (I think he was using him as the very example of extreme caution and attention to detail). My own example did kind of accuse Sheck of a certain kind of incaution (intentionally entering into a situation that overbalanced his margin for error) - but I think he did it with full knowledge and acceptance of the risks it entailed. I would have been proud to have have been his student, friend or dive buddy - unfortunately, he died shortly before I would have got my chance to meet him.

Exactly...

[Sid]

thanks for all the replys but we are getting off the main topic (heavens to mergatroid even) it takes about 5 to 6 full turns to close a valve, that means about 15 to 20 hits (at a quater turn per hit) on the ceiling to close off. thats completely, or should be, unacceptable to the cave community if we are for preservation. one or two hits per dive adds up to a lot of damage. a complete roll off in one dive tells me i dont deserve to be in a cave. thanks for contunuing this thread. ltb7733

Let's see 6 turns x 2 x pi x 1 = 18 inches of circumference played out on a cave contact to completely roll off a valve w/ a 2 inch diameter knob, if the knob is rubber and you just skim the ceiling like on an exit through the lips where let's face it the ceiling gets higher and higher everyday due to the scrapes. Anyway you can get some spectacular roll off's without really banging the ceiling, I even got roll-ons with tanks sliding in the back of the truck, or something sliding along the knobs, especially love those quick on quick off 300 bar valves with rubber wheels.

Sid

[NitroxWarrior]

thats a good point, it is possible that at some point you could possibly roll 18 inches of valve, it woulf have to be solid contact to do it though.

[Gary]

Sorry, banging the ceiling even once or twice on the dive seems like a crime to me - much less banging and scraping enough to roll off a valve.

If it's poor bouyancy control theperson probably shouldn't even be there. If the cave requires that much scrapping you should be at least be considering sidemount (or some other method) to try to minimize the damage to the roof.

[DeWayne]

6 turns x 2 x pi x 1 = 18 inches of circumference

Yo Sid, are you only counting half turns there? Six full turns would be more like 37.7 inches.

[NitroxWarrior]

Oh yah, right about that. I thought that looked fishy when i read it. Anyway, I never hit the ceiling but I'm sure that eventully if the circumstances are right it could happen, especialy with sombody inexperienced. I dont worry about it but I still use a guard, mostly because I'm more afraid of breaking the valve or first stage

[bullfrog]

Anyway, I never hit the ceiling[/quote] Really?

[Stu]

Have you ever actually done a cave dive, Nitrox?

Throughout just this post you have constantly contradicted and retracted your statements, been intolerant of other divers and even swimmers (learn the difference between "loose" and "lose", btw) and talked unrealistically about how great your own diving is. Your recent comment where you say that "Sheck was a great guy, but I never met him" is just stupid - no disrespect to Sheck (I never met him), but how would you know he was a "great guy" unless you *had* met him? From reputation, I'm sure we can all agree that he was a great exploratory diver who continually redefined what was possible in diving, but that doesn't say anything about his personality.

As for trying new setups in a cave being stupid, why use a valve protector? Not exactly a "widely accepted configuration" in the cave community (another contradiction in your posts). IMO, a valve protector on *top* of your tanks is a serious entanglement risk, unlike the same configuration mounted inverted where you can reach it. Unless it's a custom cage which has mounting struts front and back, you are adding something in an almost unreachable position which is an open line trap. Now you don't only need to get line untangled from your first stages and valves, but also out from under the cage. I have enough trouble reaching high enough to get my valves behind me. with this setup, I'd need to be able to comfortably reach all the way to the tank necks to be sure of being able to get out of an entanglement as well as be able to reach under the protector from above to get to the back of the isolator valve.

If you're going to respond to this and actually keep some credibility, I suggest you actually put some thought behind your post this time.

Uhh, and back to the original point of this thread (which appears to have been lost along the way), I don't think roll offs are a common problem in cave diving at all. However, they're something which can happen, and which it's necessary to cover in training etc. PADI train you to put a fully assembled BC on at the surface - how often have you had to do that since an Advanced OW Diver course? I was lucky enough to see one at the weekend. I figure they do it just for entertainment :-D

[Gary]

Up late and early huh Stu? ;-) Great talking to ya!


I'm sure we can all agree that he was a great exploratory diver who continually redefined what was possible in diving, but that doesn't say anything about his personality.
Nitrox knows someone who knew Sheck personally and gets more stories then most of us are lucky enough to hear. :)


why use a valve protector? Not exactly a "widely accepted configuration" in the cave community (another contradiction in your posts). IMO, a valve protector on *top* of your tanks is a serious entanglement risk, unlike the same configuration mounted inverted where you can reach it.
I used to use "Cobra Guards". Got them after knocking a reg and causing an expensive repair and a slow leak. (Yes, I was guilty of hitting the roof as well I'm ashamed to admit.)

Later I kept it on just to piss off the DIC (sp?) divers - even after I busted a screw on one of them and had to dive with just one. ;-)

I got a line in the guards once in a low spot and didn't have too hard a time getting them out with the guards over my head. I think if the same had happened behind me with inverted tanks it would have been much harder.


PADI train you to put a fully assembled BC on at the surface - how often have you had to do that since an Advanced OW Diver course?
Are you kidding? Nothing is more fun then throwing your doubles overboard in rough seas and putting them on on the way down... (at least when you don't have stages as well)

[NitroxWarrior]

Have you ever actually done a cave dive, Nitrox?

Throughout just this post you have constantly contradicted and retracted your statements, been intolerant of other divers and even swimmers (learn the difference between "loose" and "lose", btw) and talked unrealistically about how great your own diving is. Your recent comment where you say that "Sheck was a great guy, but I never met him" is just stupid - no disrespect to Sheck (I never met him), but how would you know he was a "great guy" unless you *had* met him?

when did I say I have never met him? I have met (only once) and my father was freinds with him for a long time even when my dad was too old to dive. He was in fact a really nice guy.

I also am contradicting myself alot because I have mixed felling about this stuff. I when into caving head on when I was younger and now that several of my freinds have been killed or hurt when caving I've slowed down alot. I am a very cautious diver now, I never push the charts, penentrate restrictions I'm not comfortable with, etc.

[Puttzer]

When I first got certified as a cave diver I frequently hit the ceiling: at least once every dive.

As my skills have progressed, I now still frequently hug the ceiling but rarely hit the ceiling.

I am an ordinary cave diver with just over a hundred cave dives. That's not a lot of cave dives.

So what am I missing? Why the guards and worries about hitting your valves and rolling them off?