PADI Tec Valve Drill -- Question(s)

[Diver0001]

Depending upon how you tie the knot and burn the line, you can get more security from cave line than other breakaway methods and yet still be able to break the knot.

Care to share? I use the GUE cave-line technique on my clips and I'm pretty sure if someone winched me out of the water by one of those clips that it could carry my whole weight....

R..

 

[ucfdiver]

Donating a clipped off long hose is just silly....what happens if the bolt snap is jammed?

 

[Trace Malinowski]

Care to share? I use the GUE cave-line technique on my clips and I'm pretty sure if someone winched me out of the water by one of those clips that it could carry my whole weight....

R..

If you have ever tied a proper knot and burned it with a lighter to the point where it gets "overdone" you'd be on the right track. One of the tests that is normally done after burning knots is to pick at them and pull on them to see if they still hold. Those that break are replaced. Well, if training standards call for a breakaway, but you'd rather use nylon line in place of the popular cable tie and O-ring breakaways, you simply use #24 nylon line or thinner, use a double wrap and burn it so that it holds well for normal use, but will snap if twisted or pulled hard. Tie it so that the knot rests on the bolt snap rather than the hose. Play around with this a bit and you'll figure out the "sweet spot" for durability and give. There is no real advantage to this than any other breakaway other than if done right they can last longer than cable ties and O-rings. The margin of error for achieving the desired result is such that you can have a poorer hold than you want. It just takes some trial and error. Some people want the cave line in place of obvious breakaways because they are afraid of being teased. I don't use breakaways in classes, but this was just a trick I learned along the way.

Donating a clipped off long hose is just silly....what happens if the bolt snap is jammed?

While donating the regular from the mouth is the preferred method to handle most out of gas situations and should be the most drilled method, the possibility of running out of deco gas simultaneously necessitates the ability to react to the situation and donate the long hose while it is clipped off to the chest D-ring. Many entry level tech divers use single AL40's for decompression and may misjudge how fast gas goes at depth - especially when constructing ratio deco ascents to take advantage of the oxygen window effect or when teams are slow to complete gas switches. When maximum time for an S-curved ascent is done at the 70 and 60 foot stops deco gas will be consumed surprisingly quickly. If the shallow stops are flip-flopped by extending the 20 foot stop divers often find themselves on fumes near the end of the dive. If one team member switches at 70 feet and needs to wait for others to switch who are less proficient, a planned 5 minute deco stop at 70 feet may find a diver using deco gas for 6 or even 7 minutes at that depth since the deco time starts after all team members have switched.

It is not an unlikely occurrence for an entire team to be very low on deco gas. A diver may be OOG or drawing gas like sucking a golf ball through a garden hose on the deco bottle just as on OOG signal comes from a teammate who expects a reg. At this point donating the OOG or nearly OOG reg isn't an option. But, the ability to unclip and donate the long hose while clearing the long hose of the deco reg is an option. True, the diver giving the OOG signal can switch to his own back-up regulator, but he also might be so well-drilled to receive a reg in that situation that "plugging the hole" will solve the immediate problem without added stress.

Many rebreather or sidemount divers may also have the long hose clipped during an OOG situation and they'll need to deploy it.

My philosophy is that a tech diver needs to have a special forces mindset and be able to operate as a unified team with standardized procedures, but also needs to be able to operate independently as well as think outside the box and react appropriately when things happen that aren't textbook.

But, I do agree with you that training divers to donate the clipped off hose rather than a working deco reg from the mouth is silly.

 

[Diver0001]

thanks for the detailed explanation, Trace.

R..

 

[ajduplessis]

Valve drills are there to form muscle memory and quickly shutdown the problem valve/post. The objective is to save as much gas as possible. I will shut down the suspected post and isolator in the same move with both hands. I real life situations there is no time for fancy stuff and signals. Fix the problem and then communicate, this can also be done on the move. I typical free-flow will drain a cylinder in quick time.

Modified Valve Drill

Purge Backup
Shut down right post and isolator - breath down and switch
Open right post and purge
Shut down left post - breath down and switch
Open left post and purge
Open isolator

This is the entire drill and should be completed in 40 seconds without depth change.

 

[ucfdiver]

Fix the problem and then communicate, this can also be done on the move. I typical free-flow will drain a cylinder in quick time.

I think this logic is a bit flawed. You really need to signal at the same time you're shutting the valve down so that help is on the way. As long as your buddy gets there, fixing the gas leak isn't necessary-- they'll have enough gas to get you to the surface. Without the buddy, you're at the mercy of time.

 

[Ste Wart]

I think this logic is a bit flawed. You really need to signal at the same time you're shutting the valve down so that help is on the way. As long as your buddy gets there, fixing the gas leak isn't necessary-- they'll have enough gas to get you to the surface. Without the buddy, you're at the mercy of time.

No that logic is flawed. A gas shutdown takes moments when well drilled. Your buddy could have his head stuck (not literally) in a porthole or have his focus on his camera. Why bother getting his attention, fix the problem, then go get him and ascend.

 

[gsk3]

No that logic is flawed. A gas shutdown takes moments when well drilled. Your buddy could have his head stuck (not literally) in a porthole or have his focus on his camera. Why bother getting his attention, fix the problem, then go get him and ascend.

Judging by the number of folks I've watched head off towards the surface while they aggressively shut down a valve (myself included), and judging as well by the speed with which I've seen certain divers shut down a valve *while remaining in contact with their team*, I'd say it's more than possible to do both.

I was taught "fast is slow, slow is smooth, smooth is fast", which certainly feels true when you're doing valve manipulations, even when the instructor is pointing an air gun somewhere behind your head. I don't think that style and speed are mutually exclusive, as long as you were taught style first.

Air gun? Aren't those banned in PADI Tec classes?

 

[ajduplessis]

I think this logic is a bit flawed. You really need to signal at the same time you're shutting the valve down so that help is on the way. As long as your buddy gets there, fixing the gas leak isn't necessary-- they'll have enough gas to get you to the surface. Without the buddy, you're at the mercy of time.

The longer you take to save gas the bigger the problem for you and your buddy!
Signalling someone you are losing gas when it is pretty obvious is flawed IMO!!!

 

[gsk3]

The longer you take to save gas the bigger the problem for you and your buddy!
Signalling someone you are losing gas when it is pretty obvious is flawed IMO!!!

Again, you're assuming it takes any more time at all. If you can shut down both the isolator and one valve at the same time, you can take signal and shut down a valve at the same time.

Now cue the argument about whether isolation-first is a good idea or not.