Question about a situation

[LeadTurn_SD]

I am about 2 days back from Bonaire :depressed:where i completed the SDI solo diver course

One thing that caught my eye in the manual was that a ruptured LP hose can drain 80 cu foot of gas in 83 seconds. (Apparently based on a study by the Advanced Diver Magazine). A bust disk failure is a little faster than that. My reaction to the manual - blimey that is faster than I thought. I am going to be practicing valve drills on my doubles in the next few dives.

In any event even from 60 foot I am not going to be able to react, swim to the surface and possibly get in my safety stop in 83 seconds (assuming that I have 80 cu ft of gas at the time of failure). My luck is that the failures always are at the time when my tank is 2 /3 empty giving me even less reaction time. The good news is that these failures are rare.

Catastrophic failures that result in immediate inability to access the air in your tank(s) are indeed VERY rare.

1.) For a single tank, a blocked dip tube (by rust flakes, crud) in an improperly maintained tank will do it (Dr. Bill on this board had it happen to him, had to CESA from 70 feet???).

2.) Another board member had the turret bolt on his Scubapro Mk5 shear, resulting in the turret falling off.... taking all of the LP hoses with it.... instant loss of all air.

3.) Many board members have witnessed/experienced blown tank valve o-rings. Air loss is not immediate, but you need to get to surface fast.

4.) Failure of high pressure seat. Results in both regs freeflowing, and possibly the BC inflating. Always an exciting situation.

5.) Failure of any other o-ring, hose, burst disc can result in fast or slowish air loss.

6.) Freeflows from various causes.

While the most common cause of OOA is certainly "operator error", there are (rare-ish) equipment failures that can result in the same situation.

So when I dive, either solo or with a buddy, in the back of my mind is this thought: "If I were to go OOA right now, what would I do"?

From less than 60', and without a buddy, I just swim to the surface at 60'/min. But I'm not comfortable anymore >60' without redundancy (buddy or pony/stage). I'm confident I can reach the surface from greater depths, but not at 60'/min.

Best wishes.

 

[DwayneJ]

I am about 2 days back from Bonaire :depressed:where i completed the SDI solo diver course

One thing that caught my eye in the manual was that a ruptured LP hose can drain 80 cu foot of gas in 83 seconds. (Apparently based on a study by the Advanced Diver Magazine). A bust disk failure is a little faster than that. My reaction to the manual - blimey that is faster than I thought. I am going to be practicing valve drills on my doubles in the next few dives.

In any event even from 60 foot I am not going to be able to react, swim to the surface and possibly get in my safety stop in 83 seconds (assuming that I have 80 cu ft of gas at the time of failure). My luck is that the failures always are at the time when my tank is 2 /3 empty giving me even less reaction time. The good news is that these failures are rare.

I'm not sure I understand - if you are diving doubles, it takes say less than 15 seconds to isolate a tank? Even if you don't know whats going on and shutdown the manifold in a few secs, you have saved half of your remaining gas and have plenty of time and air to return to the surface? Doubles training and associated drills are around isolating the fault at depth.

At 60' you will have plenty of air (EAN21) with doubles and likely be running into no deco limits...

Dwayne



Dwayne

 

[Dive Bug Bit Me]

'm not sure I understand - if you are diving doubles, it takes say less than 15 seconds to isolate a tank? Even if you don't know whats going on and shutdown the manifold in a few secs, you have saved half of your remaining gas and have plenty of time and air to return to the surface? Doubles training and associated drills are around isolating the fault at depth.

I didn't fly my doubles to bonaire. I used a 80 cu tank for most dives (including solo) then rented a 40 cu pony for the solo course. I do prefer doubles for the redundancy.

Point I was making was that relying on a failure to still allow enough air to for an ascent (including possibly a safety stop) is not going to work for all failures. Again I stress that these equipment failures are incredibly rare. See the quote I included from SPD 135.

 

[dumpsterDiver]

What Joel said in his first post. Todays gear is not gonna fail if maintained properly (pretty hard rule of thumb). There is absolutely no reason for a modern diver to run out of gas. Yes I know there may be an occaisional hose blow or an o-ring issue, but not a catostrophic failure that you can not safely swim to the surface and possibly even get your safety stop in. Gas Management, Gas Management, Gas management. Learn it and dive by it religiously. If you do, you will never have an issue. Most of the other things are a choice between the "lesser of two evils" and the risk of injury is very high. If you monitor your gas and manage it, there will be no issue for you.

That is a very silly attitude.. If you watch your gage and check your gear, you will never have an issue?????

I can't count the times i have seen regualtors totally fail comming out from an OH on the shop. I have seen hoses blow several times (for me it was only once on the dive platform).

I am prepared for a failure of my scuba unit, regardless of the cause.

 

[DevonDiver]

Yep...all this talk of 'impossibility' regarding kit failure is ludicrous. It's a 'law of averages' thing. Just because certain posters haven't had an issue yet, doesn't mean that kit issues cannot happen.

Cold water causes Freeflows. That's not rare. I ran OOA on a freshwater 36m during winter in the UK due to freeflow. I was a Rescue Diver at the time...approx 70 dives. The freeflow happened as I finished my initial descent at the start of the dive. My 15L tank emptied before I got back up to 20m. I breathed from the reg (as taught on OW) and it literally crusted my teeth with ice (ouch). Luckily I had a pony for the remainder of the ascent. If I hadn't had the pony, then I would have been on a CESA...as my buddy was still flustering a few meters beneath me and was lost in bad viz (I could only see bubbles passing me).

Kit can go wrong. Especially SPGs. I had an SPG failure. It stuck at 110 bar. Luckily I caught this issue whilst doing kit maintenance at home. However, this could catch divers out... and leave them OOA, despite them implementing otherwise good dive procedures.

I've seen HP hoses and SPGs blow out before. That's a quick route to an OOA situation.

I've seen divers on deep dives, experience an unrelated incident, lose control of their breathing...and suck a tank down in seconds. The last time I saw this...was a giant German DM trainee in Thailand. It was the first time he got attacked by a (very persistant) Trigger Fish. It chased him (fast) along the the bottom for about 200m, at a depth of 25m. He had big lungs and was breathing hard (panic + exertion). His tank went from 170bar to 30bar in the time it took him to sprint-fin that 200m (less than a minute).

On several occasions, I've had to share air with divers who miscalculated their requirements for ascent, having completed deep (40m) wreck dives. They had planned their air consumption, but their calculations weren't conservative enough...SAC can and does change. A little narcosis... working slightly harder than normal in current....heart racing with excitement on a great dive....a minor, unavoidable delay in ascent... If they had been separated from me, then they would have been doing CESA from somewhere above 20m. And yet they went through all the right steps for dive planning...

I've also experienced an incident before, where I ran very low (not out) of air, due to assisting another panicked diver. They got OOA (panicking - massive SAC increase) ...so I shared mine with them. They couldn't restore proper breathing and sucked down my tank at an incredible rate. It took a while for me to get us both up, as the other diver needed to be lifted (still panicking), reassured, buoyancy controlled etc etc. I needed to orally inflate for both of us on the surface. Because air was so low, I basically let him have it all for the last 12-16m of the ascent...and did a CESA myself (well, maybe a few sneaky half-breaths..).

Go figure....sh1t happens sometimes.... I opt to prepare for it, rather than stick my head in the sand and claim it'll never happen if I do everything right

There's a word used to describe the attitude in which you feel you are too good to get it wrong.

That word is Complacent

Rule of thirds applies to overhead environments. Maybe a good idea for soloists also. It can be applied to recreational dives... but if you're paying to do those dives, it would be a wasteful and un-economical option. It also doesn't help if you have a kit failure.... and kit failures can happen.

The fact remains. OOA can happen. It can happen to even the most diligent and conservative divers.

There are three ways to deal with OOA incidents.:

1) Air share with buddy.
2) CESA.
3) Redundant air source.

There are many reasons why you shouldn't rely 100% on a buddy. If you dive below your 'personal CESA limit', then you should have a redundant air source.

 

[Mark Michaud SELAUSAR]

In the context of this forum, "Solo Divers", it is not silly. I would bet that over 90% of OOA is due to lack of monitoring gas and the economic issue of "I paid money for this so I want to get the most out of the dive". Yes, there are instances that gear can fail, but..............If you solo dive you are completely responsible for the gear you use, it's maintainance, making sure it works before you start a dive, etc.

You are solo....no buddy. Situational awareness should be high at this level of diving and personal safety and responsibilty is even higher. We all should have a back up plan in case of an OOA, but the real issue is people don't manage their gas and run out of gas much more frequently than gear failures. There should be redundancy in the case of a failure; stage, pony, buddy bottle, etc. This gas is ONLY for OOA due to failure or rescue of another. I stand by the rule of thumb that todays gear is solid. If you manage your gas you will not run out of gas. Have a back up plan concerning CESA and such, but the real (time of thinking) should be spent on gear maintainance, gas management, and situational awareness.

Yes there are times that an oring extrudes, and other things happen, but that is still the exception. Just because "It happened to me" does not mean the gear, tank, etc, was maintained properly. Was it my gear, my tank, etc? Sure it can happen but it will happen less if proper attention is given to these items.

Diving deeper than 60' you should have a secondary source of gas that is more than a few breaths. If you choose to perform a rescue you have to remember that you may not have enough gas for the both of you and you are in risk of becoming a victim yourself which violates the rescue rule of don't become a victim. That is a choice you have to make and negates the premise of this conversation. I, as probably you, would try to rescue. This is about diving solo and what ifs when you are solo and you do run out of gas. Can you breath off of your bladder?

The discussion has done what it always does............changes to, Prevention in the first place. Personally I believe, Yes, you can breath off of your bladder given enough gas in there. From 50' you are only gonna breath 2 or 3 breaths and it will probably get you to the surface without embolizing and if time is right, without getting bent. Probably won't get a lung infection, but there is that chance. At this point, for whatever reason, you are OOA and have no choices.

Diving is about risks, as is any other sport. How I manage my risks is the key. In solo diving "I" have the obligation to stack the odds in my favor by using my tanks, my gear, my redundancy, etc....all of which I am responsible for maintaining and verifying things work like they should. I am responsible for having a back up plan in the case of a failure. I am responsible for deciding when economics take precedence over utmost safety. I understand that paying for a dive you want to get the most out of it. I generally breath my gas below 800 psi when on an ocean dive. But...I have plenty when I ascend to 20' or 15'. I use the extra for my stop which is usually very long because I am preparing for my next dive.

Again, in the course these things run, I believe preventative planning will place the chance of a catastrophic failure at the very bottom, and the risk of running out of gas in the first place, even lower. Stuff happens, but it happens more because of our lack of attention.

Saying "it is silly".................I don't think so.

 

[captain]

Dumpster diver mentions failures occurring on regulators just out of overhaul, that is not a failure of gear it is a failure of proper overhaul which is why I firmly believe is that any solo dive be able to correctly overhaul his own gear.
Some will say they can't get parts. I say let the shop overhaul it to get the parts then tear it apart and do it again to be sure it was done correctly.

I have never had a regulator fail or blow a hose in 50 plus years but I have been rebuilding my own for 50 plus years. I don't carry redundancy and the CSEA is my back up which I have never had to do because of OOA or failure .

 

[BoltSnap]

Some will say they can't get parts. I say let the shop overhaul it to get the parts then tear it apart and do it again to be sure it was done correctly.

This is a very bad advice indeed. Many of regulator parts will be unusable or actually dangerous to reuse if installed and then disassembled and reinstalled. Some parts will HAVE to be replaced if they were disassembled even if they were brand new.

There is more harm to do what you said to do than using the regulator as is after it comes back from the repair center. If you are in doubt about the quality or the "correctness" of the repair job, please ask the dive shop to give you a full tank and test everything BEFORE you leave the shop or go diving. I actually insisted that my customers do this when picking up their serviced equipment before leaving the store. You can also do your own visual inspection of the equipment including hoses, etc. before you dive. Again, do NOT disassemble your regulator on your own.

There is also a question of the special tools and torque wrenches that have to be used to assembled regulator parts. Trying to disassemble or assemble the regulator without these specific tool will also lead to potential dangerous damage to the regulator. One such danger is a cracked first stage body or yoke because somebody applied way too much "elbow" power when assembling the first stage and did not use the proper size torque wrench.

Please also note that the "solo" diver has no access to all of the frequent special bulletins or advisories legitimate repair centers receive from their manufacturers for special instructions on how to address some issues with their respective products.

 

[Mark Michaud SELAUSAR]

Man Captain, Us Louisiana Boys are taking an ass kicking today

 

[captain]

This is a very bad advice indeed. Many of regulator parts will be unusable or actually dangerous to reuse if installed and then disassembled and reinstalled. Some parts will HAVE to be replaced if they were disassembled even if they were brand new.

There is more harm to do what you said to do than using the regulator as is after it comes back from the repair center. If you are in doubt about the quality or the "correctness" of the repair job, please ask the dive shop to give you a full tank and test everything BEFORE you leave the shop or go diving. I actually insisted that my customers do this when picking up their serviced equipment before leaving the store. You can also do your own visual inspection of the equipment including hoses, etc. before you dive. Again, do NOT disassemble your regulator on your own.

There is also a question of the special tools and torque wrenches that have to be used to assembled regulator parts. Trying to disassemble or assemble the regulator without these specific tool will also lead to potential dangerous damage to the regulator. One such danger is a cracked first stage body or yoke because somebody applied way too much "elbow" power when assembling the first stage and did not use the proper size torque wrench.

Please also note that the "solo" diver has no access to all of the frequent special bulletins or advisories legitimate repair centers receive from their manufacturers for special instructions on how to address some issues with their respective products.

Tell that to all the regulators I have disassembled and reassembled over the years with the same parts and not had any problems.