Safety Pressure

[The Chairman]

I would like to know if there is any real factual basis or if they are mere conjecture.

Claim:

The problem with all these crutches, like a computer that beeps to let you know you are running low on air, is that eventually people rely on them.

I find the opposite to be true. Computers can and will alert people to incredible deficiencies in their diving methodology. Buddies are far less apt to point out such flaws as running your air too low, ascending too fast, missing a safety stop or exceeding time/depth limits. Why take away such a valuable tool from those who might not get to dive with astute buddies? My Cobra taught me to ascend far slower and then do an actual safety stop. This was something that was not high on my instructor's list of good diving habits.

Claim:

No beep means you have air or a broken computer. If they reversed the logic and made it beep to mean you had air you would have a valid test.

Again, I find the opposite to be true. During initialization, most computers will turn on every pixel and light and even beep when done. This will alert you to troubles before you dive. Computers fail for sure, BUT NOT NEARLY AS OFTEN AS DIVERS FORGET TO CHECK THEIR GUAGES. The problem lies in that divers feel that they do not need any training to use their computer competently. The converse is true.

Furthermore, I think air integrated computers are phenomenal. Not only do they let you know how much air pressure is left, but they calculate remaining time based on depth and consumption. Most casual users never get a feel for how much time they would have at any particular depth so this helps them to not overstay their welcome.

You can call them crutches, gizmos or whatever to let us know your distaste for them. I see them more as redundancies that help bring the distracted diver back to reality before the ca-ca hits the propeller. How many people have benefited from low oil/low brake/low gas lights in their cars? The technology is cheap and reliable enough to offer the same type of feedback for divers.

For what it’s worth… I have brought no more “facts” to this table than any other poster. These are merely my humble opinions based on my observations of hundreds of divers. I am not trying to disparage what they are saying as much as I am trying to offer a counter point of view.

 

[MikeFerrara]

NetDoc once bubbled...
I would like to know if there is any real factual basis or if they are mere conjecture.

Claim:


I find the opposite to be true. Computers can and will alert people to incredible deficiencies in their diving methodology. Buddies are far less apt to point out such flaws as running your air too low, ascending too fast, missing a safety stop or exceeding time/depth limits. Why take away such a valuable tool from those who might not get to dive with astute buddies? My Cobra taught me to ascend far slower and then do an actual safety stop. This was something that was not high on my instructor's list of good diving habits.

you might have a point. Maybe it's more of a crutch for instructors so they don't have to teach the stuff.

Claim:


Again, I find the opposite to be true. During initialization, most computers will turn on every pixel and light and even beep when done. This will alert you to troubles before you dive. Computers fail for sure, BUT NOT NEARLY AS OFTEN AS DIVERS FORGET TO CHECK THEIR GUAGES. The problem lies in that divers feel that they do not need any training to use their computer competently. The converse is true.

The diagnostics only mean it worked when you turned it on. From an engineering standpoint the logic is wrong. As I said if it is to be relied on it needs to be fail safe. That's not my opin ion but fact.

Again divers who forget that they need to manage their gas aren't ready to be turned loose yet. IMO, of course.

Furthermore, I think air integrated computers are phenomenal. Not only do they let you know how much air pressure is left, but they calculate remaining time based on depth and consumption. Most casual users never get a feel for how much time they would have at any particular depth so this helps them to not overstay their welcome.

"Casual user" is an interesting term. Maybe divers shouldn't be so casual about their gas supply. I know before I begin a dive if I have enough gas to finish it and for contingincies. By the time my computer beeped it would be time to put my head between my knees.

You can call them crutches, gizmos or whatever to let us know your distaste for them. I see them more as redundancies that help bring the distracted diver back to reality before the ca-ca hits the propeller. How many people have benefited from low oil/low brake/low gas lights in their cars? The technology is cheap and reliable enough to offer the same type of feedback for divers.

Redundancies? It might not be so bad if that was the way they were used.

Ah.... dummy lights. I'll bet there are a few burned up motors and transmissions because of them. Cars should have gauges. the lights are junk. The oil light never comes on so there isn't any need to ever put oil in the car right?. Or...is the bulb just burned out?

I think that if you assume people are idiots and treat them like idiots they will prove to be idiots.

 

[The Chairman]

I think that if you assume people are idiots and treat them like idiots they will prove to be idiots.

I guess that's why I avoid doing just that. Most people will rise to YOUR expectations... no more and no less. The trick is to require excellence in your diving and theirs.

Again we agree:

Maybe it's more of a crutch for instructors so they don't have to teach the stuff.

Most instructors should emphasize a lot more skills than they do. Incompetence in students is directly related to incompetent instruction. This is where computers are the biggest help, in that they can keep instructing after the class and fill in some of the blanks that the instructor left out. Not every diver will take a course from one of us.

As for:

"Casual user" is an interesting term. Maybe divers shouldn't be so casual about their gas supply. I know before I begin a dive if I have enough gas to finish it and for contingencies.

Casual denotes frequency of diving as opposed to a lackadaisical attitude about one's safety. Obviously, the complexity/difficulty of a dive will determine just how "casual" one might be to attempt it. I don't feel that all divers should reach the rank of "Jacques Cousteau" before they hit the suds. There is no way of getting weekend warriors to commit the same amount of time and effort to perfecting our craft as we do.

 

[Braunbehrens]

I think we can all agree that all divers should be more aware when diving, and that instruction could be improved for the most part.

As for the blinkelights, when do you go get gas (automobile)?

I fill up if I know I'm going for a long drive. However, mostly I drive around town. I typically don't even look at the gas gauge, I go get gas when the light comes on. I still have plenty of gas at that point to run my errand, and I know to get gas before the next time I need the car.

If there was no light, I'd probably take a look at the gauge every time I start the car.

Running out of gas in a car is a lot less serious than under water....

 

[netmage]

Ummm, I think I left you guys with the impression that we were diving ignorant of our remaining psi waiting for the computer to alert us... Far from the fact, we were routintely checking both computer and SPG throughout the dive.

We were diving at a local quarry, on one dive we stuck to the shallow end , ~20ft, another the deeper side, ~46ft. All through training we had hammered into our heads to not let the tank run dry, or risk running out of air, damage to the tank valves, etc. With each dive we ended up surfacing and making a surface swim back exiting the water with 400+psi.

I'm just curious if for the profiles we were diving - were we being overly cautious? right on the mark? not cautious enough.

 

[MikeFerrara]

netmage once bubbled...
Ummm, I think I left you guys with the impression that we were diving ignorant of our remaining psi waiting for the computer to alert us... Far from the fact, we were routintely checking both computer and SPG throughout the dive.

There is monitoring and planning. You monitor to assure things are going as planned.

We were diving at a local quarry, on one dive we stuck to the shallow end , ~20ft, another the deeper side, ~46ft. All through training we had hammered into our heads to not let the tank run dry, or risk running out of air, damage to the tank valves, etc. With each dive we ended up surfacing and making a surface swim back exiting the water with 400+psi.

Not letting the tank run dry isn't enough.
Why the surface swim? Surface where you want to exit. Swimming on the surface is a drag.

I'm just curious if for the profiles we were diving - were we being overly cautious? right on the mark? not cautious enough.

 

[pescador775]

An 80 tank will last quite a while at those depths and, frankly, I would be ready to come out of a cold azz quarry before the tank was empty. Yes, you are overcautious if you think your tank/valve, etc are going to implode if pressure drops below 500 psi. This is part of instructor dogma and some of these rules are tainted by half truth. Your equipment will not be damaged by low pressure. After all, it began life at zero pressure. In fact, there is a small possibility that a tank with zero pressure will inhale water through the regulator if the diaphragm is depressed. However, when you climb above the thermocline and surface the tank starts to warm up creating a slight positive pressure even when zeroed out. A gauge pressure as low as 5 psi is enough to protect the tank, regulator and valving. The rule should be that if you turn blue from sucking on the regulator the pressure is low enough. :wacko:

 

[Epinephelus]

MikeFerrara once bubbled...
If any machine beeps at me while I'm diving I'll smash it wit a hammer.

I have a much easier solution. I can't hear it so I ignore it. I think the stupid SUUNTO I have starts beeping at something like 750 psi (at least that's when it starts flashing the air pressure number on and off) - and since I may be diving double 104's (500 psi in an AL 80 = 165 psi in double 104's) it must get tiresome for those who can hear it - but it doesn't bother me a bit.
E.

 

[MikeFerrara]

pescador775 once bubbled...
An 80 tank will last quite a while at those depths and, frankly, I would be ready to come out of a cold azz quarry before the tank was empty. Yes, you are overcautious if you think your tank/valve, etc are going to implode if pressure drops below 500 psi. This is part of instructor dogma and some of these rules are tainted by half truth. Your equipment will not be damaged by low pressure. After all, it began life at zero pressure. In fact, there is a small possibility that a tank with zero pressure will inhale water through the regulator if the diaphragm is depressed. However, when you climb above the thermocline and surface the tank starts to warm up creating a slight positive pressure even when zeroed out. A gauge pressure as low as 5 psi is enough to protect the tank, regulator and valving. The rule should be that if you turn blue from sucking on the regulator the pressure is low enough. :wacko:

The recommendation to exit the water with 300 - 600 psi is just to keep presure in the tank. No low presure will not hurt the valve or tank and nobody ever said that it did. However water getting in can hurt lots of things. 5 psi won't keep water out if the valve is open. That's not instructor dogma.

If I go to fill a tank and don't get a healthy hiss when I crack the valve the tank gets visualed or I don't fill it. I gotten in tanks that had a cup of water in the bottom.

 

[pescador775]

If I go to fill a tank and don't get a healthy hiss when I crack the valve the tank gets
visualed or I don't fill it. I gotten in tanks that had a cup of water in the bottom.

That's your perogative. May I ask, just what is the minimum pressure that will keep water out of a tank? I ask because you say 5 psi is not enough.