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How do you plan?
I'm pretty conservative and always plan to be able to swim out even when I'm towing a 2nd scooter. I've had some wonky things happen with scooters and other mechanical equipment that I just don't trust them enough, especially when it comes to my life. I know not everyone is this conservative. In fact, I've heard some gas plan the same whether they're doing a swim dive or a scooter dive.
So what do you do? And why?
I plan on CCR dying, buddy not noticing, scooter crapping out.... aka, enough gas to swim out at max penetration.
Always plan to survive the worst possible day of your life...
I always scooter with untouched backgas. One stage will get me, for example, p4,000' and back at JB. For anything more, I take another stage.
In a team of 3 divers on CCR and scooters, I plan for one CCR failure and one scooter failure.
If the dive is big enough to need to plan for team bailout rather than being self sufficient, then some serious predive planning takes place and methods are practiced before the dive at hand.
I was taught plan for any two failures if you have three it is your day to go.
Depends on the dive and it depends on the cave.
Sometimes enough gas to swim out. Sometimes enough scooters so that I won't have to swim out.
IMO, planning to swim out on a deep cave dive is not realistic. The deco times and gas requirements become absolutely bananas rather quickly. I always tow on deeper cave dives, and often on shallow ones too.
I also dive with pretty good buddies, which factors in a bit. So realistically we'd have to lose a pile of scooters to end up swimming.
I still plan it the way you taught me in DPV class. Assuming a two man team with at least one diver in backmounted doubles, one scooter for each diver: plan gas to be able to swim out with one total loss of backgas and 2 scooter failures at max penetration.
The only thing I hate to see is gas planning based on math exclusively versus some real testing. So many people will say I can exit from the Heinkel on an AL80 stage because I have a SAC of X, swim rate of X, flow rate of X..... my calculations show I have a enough gas. There are so many variables that I found when I simulated swims like this from different systems that I found that my mathematical planning would have left me short of a safe exit.
I once scootered to he Henkel, and swam out to see how much gas and time it would take in case of an emergency. It took me 48 minutes, and more gas than the third of a stage I used coming in. Also had a long deco. And this was a relaxed environment. Knowing you have a real emergency, most folks won't be as relaxed and will probably use more gas.
Quote:
Originally Posted by Kelly Jessop
that is a REALLY bad day. if i thought that was a possibility i would probably stay home and watch football.Quote:
Originally Posted by steve2281
you also presumably have had a team failure if your buddy and his scooters are unavailable.
as aj says above it depends on the cave. there are plenty of dives where you just aren't swimming out
Dude, it could totally happen. Picture this, a cave monster eats your buddy, and then your scooter explodes.
Quote:
Originally Posted by LiteHedded
both scootersQuote:
Originally Posted by Kevin Leonhardt
Totally possible:
http://m.imdb.com/title/tt0402901/
(Especially on a Dive Rite Arrow?)
oh i totally mis-read this scenario. i was thinking you have tow scooters. you just have one each in this case. I would plan where each diver has enough gas to swim out, especially with a gavin/SS scooter. I wouldn't plan for a gas sharing swimming exit. that's just too much and planning yourself right out of a dive.Quote:
Originally Posted by LiteHedded
but i think hitching up to tow after losing the first scooter is a great opportunity to pick up a rock or line and bust the second one. i wouldn't plan on being able to tow out
Well, when the first one exploded it would obviously take the other with it.Quote:
Originally Posted by LiteHedded
It does depend on the dive and cave. I'm not referring to something like Eagle's Nest here. It's simply physically impossible to carry enough gas to swim out of there after scootering in or to deco on bottom gas if you lose a gas. That's an entirely different thing.Quote:
Originally Posted by PfcAJ
I'm referring to basic cave dives in the 80-100' depth range. While having multiple scooter failures is not likely I have heard of it happening. And I have heard of having to swim out from significant distance because of this. IMO that was just poor planning. While bigger dives require some risk assessment and deciding what is okay to do and not to do, for most scooter dives planning for a swim exit isn't all that difficult. I know I can swim out from Stage Rock in JB (2600 p) on a single AL80 and still have gas left over. I've done it to prove the math works. And I even pushed myself a little bit and was pushing the scooter ahead of me to try to get my RMV up to simulate a stressed situation. (See Kelly's post #9). So for me a couple of AL80s will get me out from pretty much anywhere in the mapped passage of JB. I might have a bunch of deco but I'd rather have to ride a chamber than not make it out at all.
Now for another question.
Does everyone on the team need to have a tow scooter or is a team tow scooter enough for you?
a team tow scooter is enough for me
Would your planning change if you had a way to monitor battery/scooter life on the fly during the dive?
Depends on the distance. Shorter range stuff and I think a team tow scooter is reasonable. For a longer thing you need full coverage. Determining what is "long" is up for debate.
The scooter has always been felt to be the weakest link in all the dive equipment,for example we have redundant lift,regulators etc. If your propulsion such as scooter is part of your life support,then either have enough gas planned for a safe exit (which should be always) by swimming, or carry a spare scooter for all dives. I never plan for scenarios where if there is a scooter failure and will tow the person out because it is very slow and stresses the gas plan,and nobody really practices it following their DPV class to say they are proficient at doing it. I have seem so many instances of team separation because of scooters,where one team member has an issue to pause,and the other member goes around the corner-now we have two solo divers with Murphy waiting to strike. I have heard enough scooter incidents to fill the IRAP section of this forum,but I recall a team exiting from Manatee and the trailing buddy had an issue and paused. He got back on the trigger and it failed,but by this time the buddy had gone around the curve. The buddy realized after about 1000ft he had no one behind him. He went back and found his buddy,they exhausted gas by trying to figure out what was wrong with the scooter,and exhausted more gas by trying to get into a tow position that would work. The only thing that save their life was they could exit from Friedmen's,but they would never have made it back to Catfish Hotel from where they started. For many this dive was a short penetration,and a spare scooter was never part of the plan,but the spare scooter could have turned this into an inconvenience versus an emergency.Quote:
Originally Posted by RN
So in my opinion there's a few issues about the above story that make me raise an eyebrow.
We've all had some separation when scootering. But a thousand feet? That's like 7mins (ish). To me, that's just way too much and shows a lack of attentiveness by front guy.
Second issue is inappropriate response. On a resource-light dive, you can't fully dally trying to fix things. It's time2go when something breaks, especially propulsion.
Third thing is possibly not great towing skills. Done right it's not that much slower. But there's some odd methods being taught so I can't speak for every possible permutation.
Lastly is an apparent lack of reserve gas. Thirds is just too sporty on a scooter dive. More gas needs to be reserved, and that value goes up the farther you go in the cave.
Just my opinion.
You are right we can dissect that incident and find lots of problem. I have heard many examples of scooter dives that had problems,not this extreme,but were problems where better awareness,planning,and practice were indicated. But is this example too far off base? Not really. Why not dissect the dives that nothing went wrong,but were begging for a problem as seem in the first example. I recall the number of times that I have seen people "hook up" for a dive on the other side of the Heinkel or some distant location in JB,having no diving experience as team,but just a chance encounter to dive together. The predive planning is I got backgas to X pressure,and stage tank to X pressure-lets go dive. They complete the dive,and everything is successful so it reinforces the premise that this is okay and safe. But now is the time to dissect all the things that can go wrong,and what needs to be done to make this a safe dive. Looking at things like gas planning to start this thread,and even Rob's suggestion of spare scooters are the tip of the ice berg of solutions.Quote:
Originally Posted by PfcAJ
That comes back to training. There's a bunch of things being taught and it's easy to end up with a group of divers where everyone isn't on the same page.
Now of you want to get into a fun discussion, throw safety bottles into the mix. Now it gets complicated.
No, simply because there are other things that can fail on the scooter too.Quote:
Originally Posted by CCRMichael
I don't know; I think more complacency and poor planning.Quote:
Originally Posted by PfcAJ
Agree mechanical things fail first,such as relays,pulleys and switches. Makos used to have the LED meter,which had a huge amount of variability ,but once you learned your specific scooter they were quite handy.Quote:
Originally Posted by Dsix36
Led back then? That's cutting edge :)Quote:
Originally Posted by Kelly Jessop
Id be less interested in a gadget displaying battery life than in past application of the equipment. Very similar to the "math" of gas versus the "application" of gas usage.
As for gas planning, It is very dependent on the depth, distance and buddy arrangement. It seems that the more gas mixes you need the more scooters you need and the less conservative your gas planning becomes as you have more total gas rather than just bottom gas in the cave. Not to be confused with unsafe gas planning.
For example: single gas w/O2 deco and I understand not touching back gas and only using (even sacking) the stage (use 80cf and reserve 240ish cf for the entire dive); however, very difficult to plan to bring that much reserve gas to a Nest dive. So add a back up scooter and sufficient gas plus you have deco gas to assist your exit adding in a slight bit of conservatism/safety.
Bob
On a deep one (and some shallow ones ) I wouldn't touch backgas at all. Stages only. And definitely bring a tow scooter.
While we are all saying some very similar things, one of the themes I am hearing is that we would "use stages, not touch back gas". And then some throw a tow scooter in, too.
If I'm running the gas math right, that puts it some where around 1/10 gas for entrance and 1/10 for exit (with minimal overfill). Assuming single stage, double 104s. And a tow scooter. That dive would be better done swimming, if Im reading it right.
Just my thinking. If you are using a scooter, then you are either trying to extend your range or shorten the dive time. Or maybe just cause its fun! Whatever the reason, it seems reserving more gas than you would on the same dive swimming is uber-conservative. By more gas, I mean volume not 1/3rds, 1/6ths, etc.
In the stone age (only 15 years ago) my DPV class was either: 1/6ths or a tow scooter. Both were not needed. Local knowledge required, gas mgmt rules prevail and all other disclaimers.
Bottom line: I am fine with extremely conservative planning and I do not judge it--in fact, others consider me too conservative. I was once hammered due to my gas planning on a 10k dive in Manatee: "you dont need all that gas, thats too much logistics!". My comment: bring what you want but thats all you have--mine is not yours. On a dive, not much kills you faster than breathing water.
bob
The thing about reserving a large amount of reserve gas on deep dives isn't about thirds or sixths or some fraction of choice. Its about time. Time to deal with issues at depth. Keeping backgas intact helps to ensure that you've got the bulk of your gas with you at all times, and its in a sharable and isolatable format.
Fwiw, a double stage (al80s) dive with 104s to 3600, using just stages is roughly equal to 1/6th.
You can't swim out of a deep thing. Hence the need for a tow scooter.
@floridabob, care sharing the gas plan for manatee?
A quick napkin estimate of 2k on 1/3 stage that would lead to 5 Al80 + back gas kept for reserve. With that distance I'd also expect a tow scooter.
Assumptions:
2k per 3rd using ginnie flow (manatee is higher)
Amount of stuff being towed would also reduce efficiency...so the penetration distance may drop to 1500' per al80. This could increase the number of stages to 7-8
half+200 on stages for me.
Should have started that with the fact we were on rebreathers, sorry. But, i'd not need that many stages and tow scooter would be required.Quote:
Originally Posted by patpicos
AJ--my statement about reserving more quantity than when swimming was based on: what posters were saying; not what I would do.
Example: Ginnie to Hinkle swimming uses less than 1/3 of 2 stages and again a bit less than 1/3 on 108s at 3600. Scootering using 900 psi in a stage. So, I was using me but extrapolating using others methodology: stages only. So, more in reserve on scooter than swimming was based on that w/time to poke around and get out.
Again, no argument here on reserving gas, just trying to understand.
Manatee Dive. Total run time of approximately 300 minutes w/45-55 deco.
Team of 3 to 10k w/1+ hour survey time, 85 minutes to 8k, 50 minutes out. Yes, thats 8k from Friedmans but we get in at Catfish...so 85 minutes from Catfish to start of survey which includes:
1 AL 80 dropped at the "sign"
2 AL 80s at the crack
3 back up scooters dropped at the Siphon T
arrive at 8k about 85 minutes
Me: 2 95s at 3800; buddy --2 85s at 3800; buddy 2--2 LP 80s at 3800
We have done this dive multiple times and thats how its worked out. Quick gut check of all breathers dying and all scooters and we all swim out w/gas to spare.
Others doing similar dives use 2 scooters w/4 stages and 108/104s in OC.
Long and far but not deep. Yes, I love the safety of 3 back up scoots even though same say its overkill.
I think it's both poor training and complacency and poor planning. I've heard of DPV classes in which instructors cover the in water skills but there isn't any discussion about gas planning. That's the most important part of the class IMO. I'm less interested in how well someone can tow someone else or match speeds while sharing gas than I am in how well someone can plan a dive so that there is sufficient gas to get out of the cave alive if something goes wrong.Quote:
Originally Posted by Kelly Jessop
But then there are those who get good training and learn all about proper gas planning. They end up going out and doing a bunch of dives with nothing ever going wrong and they start to think maybe their instructor was being too conservative. They can go a little farther and it won't be a big deal. Until it is. It doesn't help that we have scooter like the SS Magnus that can travel over 200 fpm and get really far back in the cave. While I could get 4000' in and out with my Mako I never attempted that without having enough gas to swim out. I just didn't trust it that much. A 4000' dive is nothing with my Magnus though. I still plan enough gas to swim out but I also need less gas to get in because my Magnus can travel twice as fast as my Mako could.
Oh, and buddy separation is all too common. The only reason I've ever had to withhold a card is for that reason. It's too easy to lose track of a buddy when you're travelling 150-200 fpm. It's one thing to have a short separation of maybe 30 seconds but anything longer than that is lack of awareness.
Let's complicate things even more. Planning a dive that involves both scootering and swimming. Most of my dives are exactly that. In fact, I don't think I've ever planned a dive in which I've been on the trigger the entire time. I liken it to the express train . I take the train to my stop and then get off and do my dive. So now I have to plan gas to scooter in, gas to do my swim dive several thousand feet back, and gas to get out if something goes wrong.
Seriously? That's a thing you teach?Quote:
Originally Posted by RN
No wonder this is so complicated. Learn to tow efficiently. Link up, share from your buddy's backgas, and gtfo.
I'd love to hear a reasonable situation where sharing gas while scootering is a real thing.Quote:
Originally Posted by PfcAJ
Post removed.Quote:
Originally Posted by jj1987
Sorry, my joke sounded like it was directed at Rob, whom I never even met.
It was not intended that way.
Pavao.
One can't say if that is a "thing" that Rob teaches,but it is taught,and with all skills has a correct technique,and can be don't efficiently. Where my preference would be to pass off a stage,but it if the SHTF,this can be done quite well if you have a buddy versed in it. To practioners of DIR this may seem contrary to what you are taught, but at the same time many non-DIR people have always thought GI3 was nuts in teaching people to breathe off their dump valve in an emergency. I prefer to be open minded and learn from everyone,use my ability to use critical decision making to determine what is something to keep in my bad of tricks,and what to dump.Quote:
Originally Posted by PfcAJ
i dont think it's just 'DIR' folks who can see all the problems with trying to negotiate cave passage while tethered to an out of gas diver on a long hose.Quote:
Originally Posted by Kelly Jessop
just because a thing can be done does not mean it should be done
You're dramatically increasing the odds of the reg getting ripped out of your buddy's mouth. That would be bad. It also breaks down every time you need to travel single file.
No thx.
Not to hijack the thread, but since you asked, IMHO manifolded doubles can create such a situation.Quote:
Originally Posted by jj1987
I agree it isn't without flaws and requires a lot of practice to be proficient,but as I said I would prefer to know a skill to increase my chance of survival than not. We have redundant regulators out the yin yang,so we shouldn't know how to buddy breathe to accomplish an exit-correct? About 25 years ago a team survived because they used bubby breathing when they had a serious situation. From that I made a couple buddy breathing exits for practice. Like I said something that less than ideal,but another skill set that increases my percent of survivability.Quote:
Originally Posted by PfcAJ
If you can't dive your equipment (ie reach and manipulate your valves), then sure.Quote:
Originally Posted by nakatomi
Actually it's not as bad as it sounds. We did this drill in DPV class exactly where we did the standard lights out OOA drill in cave classes. That includes negotiating a restriction.Quote:
Originally Posted by PfcAJ
Both scootering while tethered, plus going through the restriction while tethered, is actually not that difficult, assuming the rest of the skills are solid.
I think sharing gas while scootering together decreases your odds of a good outcome. To slow, too many variables, too easy to rip out the donated reg.Quote:
Originally Posted by Kelly Jessop
Getting into a proper towing position means the lead diver can go the entire exit without getting off the trigger, even through narrower bits.
Maybe someone can post the video Wes Skiles took of the diver that knocked off/dislodged his manifold at the keyhole?Quote:
Originally Posted by PfcAJ
Being able to reach anything, didn't help that guy.
To get back to OOA and scootering. Per your logic, an OOA automatically initiates towing. So instead of both divers being able to scooter full speed to their next stage bottle (or the exit), they are now sharing one single scooter and are unable to maintain visual contact.
In my experience, visual eye to eye contact is very beneficial in emergency situations. It works nicely when scootering tethered to a longhose. Try it, it's actually pretty enjoyable.
Maybe someone can. What kind of manifold was it? Some yoke thing from the 80s?
I've dropped two sets if doubles off my tailgate onto asphalt manifold first. Both times BENT the manifold. Nothing leaked.
Your scenario seems like it might work in some crystal clear training cave. Sounds like a real treat in low vis, dark line, etc.
Also you maintain visual contact via lights. The towed diver points his light forward so front guy can see it.
Quote:
Originally Posted by PfcAJ
Have you ever tried it????? I mean more than cyberanalysis,but actually trying it in the water several times.
It really can work,but it requires a lot of proficiency with using a DPV. Like I said, not a preferred method,but a last ditch skill that I have in my tool box.
Kelly, I'm not one to try things that are clearly a bad idea.
I can't see a situation where it would be a benefit or a "last ditch effort". I also would not want to put my buddy in such a compromised position should we need to do a real air share exit. I'll stick with what works.
The odds of a bad outcome are too great, this is a really really bad idea. I can't believe this is actually being taught.
Just to clarify, the way we did this was to swim next to each other, side by side, then launch the scooters and match speeds.Quote:
Originally Posted by Kevin Leonhardt
We scootered side by side, having full visual contact. Once one diver goes off the trigger, of course the other one will do so too.
Negotiating smaller areas and restrictions is of course done while not on the trigger and in single file if necessary.
Does this support a 10' hose length?
Sent from my iPhone using Tapatalk
I'm sure it would, unless the vis is less than 10' :)Quote:
Originally Posted by Garth
AJ has a point. Just clip in and tow, even if you use your scooter to help the exit.
Simpler than the alternative of speed matching, I'd think.
Bob
From the NSS-CDS Training Standards
Exit cave while gas sharing and using DPVs in full and simulated zero visibility while maintaining visual/touch contact with the guideline as appropriate.
So while I don't think this is a practical method of exiting all caves and, like Kelly mentioned, not a skill that would be performed well, or even should be performed, if it's not practiced on a regular basis. I focus a lot more on other more practical skills but I do have my students perform this skill in OW and in the overhead as required by standards. Like I stated previously - I'm less interested in how well someone can tow someone else or match speeds while sharing gas than I am in how well someone can plan a dive so that there is sufficient gas to get out of the cave alive if something goes wrong.
There are other course standards I don't necessarily agree with. As long as there isn't a safety issue (I'm talking about under controlled circumstances like with a necklaced regulator attached to a cylinder that has plenty of gas) then it gets done. If there was a safety issue then I wouldn't offer the class. And, in fact, there are a couple classes I don't offer because I feel there are safety issues with the standards - Extended Air Diver, for example.
Anyway, this isn't about agency standards but rather about real life application.
... or we could always go back to "always scooter in solo configuration, with untouched back gas."
I'm already carrying 4 AL80s. I'd have to add another couple to make that happen...
Or do a setup dive?Quote:
Originally Posted by RN
Place safeties, do setup dives.
Long range diving ain't easy.
psh. what do you knowQuote:
Originally Posted by PfcAJ
Just buy a rebreather then you never have to worry about swimming out...and forget that pesky bailout...rebreathers never fail.
Sent from my SAMSUNG-SGH-I337 using Tapatalk
4 stages is really where RBs start to become most attractive, imo.
Still need the tow scoots and safeties tho.
Typically I do a pretty good job of keeping my mind open and my mouth shut, but this is bothering me too much. I think your interpretation of the standards are whacked. In your citation above nowhere does it mention both divers on the trigger while sharing gas. You're kidding yourself if you believe that is a safe way handle an OOA situation.Quote:
Originally Posted by RN
There's only one way that meets the standards in every scenario: donor clips his scooter into tow position, grabs crotch strap of OOA diver, OOA diver drives out. They are in touch contact and prepared to handle zero vis, restrictions, etc.
Kevin I am not trying to disagree with your statement above but I was taught in my scooter class that the oog diver needs to be towed. I was told that more than likely the oog diver would be stressed and more than likely not in the best of shape to be scootering. I can see the reasoning behind your way as the diver with issue is placed in front and in control of the situation and it also keeps the procedure the same as if they were swimming. I can see the reasoning either way.
Wait, people actually scooter in Zero visibility?
I'm asking because I don't know. That seems dangerous and unnecessary but I have no training with a scooter and only about 15minutes worth of time playing on one.
I think if I was in that situation now I probably would clip it off and swim.
Interested to here some discussion of real life experiences.
Thanks
Garth
Sent from my iPhone using Tapatalk
not zero obviously. but in seriously reduced visibility it's possible to scooterQuote:
Originally Posted by Garth
Depends on who you are scootering behind. :) Seriously I think what the standards are saying is swim along the line pushing or towing the scooter simulating zero viz. At least that is what I did in my class. You can scooter in some crappy viz but you really have to concentrate on the line or you will loose it.Quote:
Originally Posted by Garth
Both diver's will be a bit stressed, they are both breathing from a single air source with no other options for gas. The only way I would put the OOA diver in the back is if the donor was a whole lot more familiar with the cave.Quote:
Originally Posted by bamafan
I had a conversation with one of my very regular dive buddies and we decided there was no GD way we would share with both on triggers separately. We laughed out loud about the concept of connection by mouthpiece.
Just hook in and go. It's a better option.
I see absolutely no reason it doesn't work or that speed matching would be required. Required. If I'm missing it, set me straight.
Practice the skill of speed matching, sure, why the hell not. But do it. No thanks.
Bob
I've scootered for short sections on the line in zero vis. Its slow going trigger-bump stuff, but it can be done.
As far as which diver goes in front, I think there's merit to both the OOG diver in front and OOG diver being towed arguments. I generally think the OOG guy should be in front as its much easier to recover the reg if its out in front of the donating diver rather than somewhere behind him if the two get separated (thanks Litehedded for the reasoning). If the OOG guy was shaken up with the big eyes look, then put him in the rear so he can zen the F*&% out and not burn up a lot of gas.
I don't see any other way of interpreting "using DPVs" other than being on the trigger. I'm also not the only one who interprets the standards this way. This is what was also done during my internships. I never said I thought this was a safe skill. I did say So while I don't think this is a practical method of exiting all caves and, like Kelly mentioned, not a skill that would be performed well, or even should be performed, if it's not practiced on a regular basis. I focus a lot more on other more practical skills but I do have my students perform this skill in OW and in the overhead as required by standards.Quote:
Originally Posted by Kevin Leonhardt
Safeties are already in place. They have been. This thread is not for my benefit but rather for the benefit of others who would like to do the dive but think it can be done with less equipment and less gas. Fortunately, pretty much everyone is in agreement and hopefully others will learn from what's being stated here.Quote:
Originally Posted by PfcAJ
Backmount rebreather won't fit. I'm still not totally comfortable with my sidemount rebreather to be doing this type of dive with it. Besides, see above ^^^Quote:
Originally Posted by FLDVR
Why teach it if its not safe (first) and practical (second)?Quote:
Originally Posted by RN
It would seem to me that both students are using DPVs while doing the towing method. Diver 1 is driving it, diver 2 is towing it out. DPVs are certainly being used and you don't end up teaching some "technique" that virtually every poster here recognizes as impractical and dangerous.
That's good to hear!Quote:
Originally Posted by RN
I agree Rob it is only ideal if done in certain systems,it wouldn't work in smaller caves at all,and should only be done with a good team dynamic that have high level of DPV proficiency with practice. But, I am reading an oxymoronic statement, it is a skill that is being taught for DPV OOA exit,but instruction may not consider it safe? What is the current state of DPV training skills people receive? I really don't keep up because I feel what I have learned in the past has served me well,but I am open minded enough to understand where the industry has gone. I feel the majority of the DPV training being conducted is non-DIR and these people are not going to respond on this thread for fear of rebuke they may receive since what they have been taught has been deemed "unsafe",so I started a poll to get a good understanding on what is being taught.Quote:
Originally Posted by RN
i'm not sure why this needs to come down to DIR or not-DIR
there are plenty of problems with this method of exit that i think are plain for everyone to see.
False dichotomy.
This is not DIR vs non-DIR,this was a set up for the people following this thread for a poll that was posted. This wasn't about defending one method over another. This was about fact seeking. Everyone can go from Def-con 5 back to def-con 2.Quote:
Originally Posted by LiteHedded
got ya. thought it was a DIR thing. but plenty of people outside of the DIR camp dive this way
Why would DIR ever worry about a gas sharing exit? They have isolation manifolds! :smt102
Because the only thing that can cause an air sharing exit is a reg failure, right?
Naw...I will save my DIR rants when they are appropriate.Quote:
Originally Posted by LiteHedded
There is no way in hell I would ever consider both being on the trigger and sharing gas.
If my dive buddy suggested such a strategy I would take her directly to UF for impending stroke or brain cancer.
It brings shame on our community that people teach such a stupid idea.
Defcon 2 is more serious than Defcon 5. Defcon 5, I believe, is "All good" and Defcon 1 is "Russia just shot nukes our way."Quote:
Originally Posted by Kelly Jessop
So, how exactly does this work? I've heard it a ton before, but I'm not sure exactly how it works. I also have practically zero DPV experience.....so forgive the question, but can you clarify this?Quote:
Originally Posted by PfcAJ
Do you breathe your stage down to 1700 (assuming AL80) and then exit on your stage, draining it completely but leaving your backgas untouched? Or would you scooter in half+200 before switching to backgas and looking around that room before turning? What do you do if you have two AL80s for stages? How would you plan that?
Quote:
Originally Posted by RN
Bingo!Quote:
Originally Posted by PfcAJ
Just out of curiosity, since you're so flamboyant in telling us how stupid this method is, please allow two questions.Quote:
Originally Posted by mdax
Are you DPV trained? If so, did you ever try this procedure during your class?
Not sure if you know how to stage dive, but I don't teach cave diving so I'm not going to get into the details of all the gas management. But pretty much the "+200" is burned up during the gas switch. Stowing hoses, droppin' bottles, etc. So at the end of the dive, the stages are effectively empty. If you have an issue, you can jettison the spent stages since there's virtually no breathable gas in them. Compare this to "thirds" where you've got 1000psi in maybe 2 or 3 bottles. That's a lot of gas totaled up, but its also 2 or 3 bulky scuba tanks that slow you down and the reserve gas isn't with you at all times.Quote:
Originally Posted by victorzamora
To keep the topic focused on DPV diving, I'd suggest that if its longer range and/or deep, you don't touch backgas (that's your reserve) and breath the stages to half+200 each. Depending on the dive I might use a stage (to half+200), drop it and go a ways on backgas. Its HIGHLY dependent on the cave and the situation. There's no one size fits all method for this.
Much more than 3 or so stages and you're getting some distance under your belt and more considerations need to take place. But still, half+200 on the stages.
I use it as a skills exercise as mandated in the standards. I don't teach it as a practical application. Same reason I have my IANTD Trimix students remove and replace their rigs underwater during class. Not only that but they have to remove the rigs, ascend to the surface, dive back down and put the rig back on. Is this a practical or safe thing to do during a non-training dive? Absolutely not. It is required by standards and it is useful as a confidence builder. That's the way I view this DPV skill. Not practical but useful as a confidence builder.Quote:
Originally Posted by PfcAJ
Towing a DPV is not the same as using a DPV. It's a matter of interpretation. I may be interpreting the standard incorrectly but if that's the case so are other instructors. Who knows, maybe this thread will get the NSS-CDS Training Committee to review that standard and either clarify it or remove it. None of the other agencies I teach through have a similar standard.Quote:
It would seem to me that both students are using DPVs while doing the towing method. Diver 1 is driving it, diver 2 is towing it out. DPVs are certainly being used and you don't end up teaching some "technique" that virtually every poster here recognizes as impractical and dangerous.
I do know how to stage dive, and have taken a class.....I was asking specifically about the DPV aspect of it. I do my stage diving differently than half+200, but I don't want to get this thread onto what stage gas management techniques you use.Quote:
Originally Posted by PfcAJ
What do you do?Quote:
Originally Posted by victorzamora
Should have been covered in your DPV class. Personally, I require my DPV students to have stage experience because we will be using them during the DPV class.Quote:
Originally Posted by victorzamora
Maybe I am confused,but I when I learned this skill it came from NACD instruction.(?)Quote:
Originally Posted by RN
I teach DPV divers to gas share side by side using both scooters. It gets the team out of the cave faster. If the team gets to a place where both scooters will not go thru side by side, then get in one behind the other configuration. This seems like common sense to me. I was taught this procedure by Larry Green who was at the time the training director for the NACD.
There is nothing written in the NSS-CDS Standards about which method should be used in an OOA situation. I did not review the NACD standards in regards to this issue as I am not certified as an NACD DPV instructor.
Rob: If you have suggestions for the NSS-CDS training committee please send them in the proper venue. I do not read this forum daily and will not see your suggestions. I will of course appreciate all suggestions you may have but will appreciate them being sent to me via e-mail to: trainingdirector@nsscds.org
Mdax-> I live close to you, so I will wait at the top of my driveway for my ride to Shands. :rollguy
That is exactly how I was taught and based on my experience with it going so smooth, I have high confidence in it being the proper approach for two skilled divers who know how to do this.Quote:
Originally Posted by Jim Wyatt
I was thinking about this thread last night. It occured to me last night what this reminded me of. When I was a little kid me and my sister had some huge rubber bands that were over a foot in diameter relaxed. We would hook them over something and see who could shoot them the farthest. Finally one of the broke so we took it and tied the handles of our Big Wheels together with it. We would ride up and down the driveway and steer away from each other and it would pull us back together. One day we were coming down the driveway playing like this. Our garage had 2 seperate doors with a small section between the 2 doors. She went on 1 side and I went on the other as we were going as fast as we could. The rubber band stretched tight and I remember pulling back waiting on something bad to happen. Finally the rubber band broke and it hit my sister and luckily all she got was a big whelp. I am not saying it can't be done but I can't think of 1 instance where it would be better than being connected to the doner. I can just see the hose getting hung on something and the best case scenario is the reg is pulled from the divers mouth. The worst case scenario is something breaks. I prefer to be attached to the diver that is donating gas. Each to there own. Oog sidemount is so far down on my list of worries that it doesn't really concern me. Now backmount and a collision that damages the manifold and causes a total loss of gas might be unlikely but alot more likely than loosing both tanks sidemount. Just look at the ceiling in the duck under in the Lockwood tunnel the next time you go. Everytime I go in there all I can think is this would be a bad place to tear a manifold up but from looking at the ceiling alot of people are hitting it.