SPG or not

[Badger7]

Were you guys also tought to hold the SPG away from your face when opening the tank since it might explode in your face?

Yes, actually to press the face of the SPG against the bladder of my BCD when turning on the tank valve so that when the SPG inevitably explodes I'm also not blinding random passerbys.

 

[34109411]

Were you guys also tought to hold the SPG away from your face when opening the tank since it might explode in your face?

Choose AI, save your eyes.

 

[Nemrod]

"Inevitably," I rather doubt.

We were also once told to back valves off a turn and a lot of other nonsense.

The lens is either plexiglass or tempered glass and there is a blow out plug in the case. I do not think we need to fabricate reasons to switch to an AI computer.

 

[Badger7]

"Inevitably," I rather doubt.

Sarcasm was implied, sorry. I've never heard of an SPG dieing an exciting death in the modern era.

 

[34109411]

 

[LI-er]

Were you guys also tought to hold the SPG away from your face when opening the tank since it might explode in your face?

Choose AI, save your eyes.

You should never look out your car windshield either because an asteroid might fall on it.

 

[pisauron]

Thread 'Exploding SPG gauge faces?'

Sep 27, 2017

I've heard anecdotal stories of exploding gauges and the need for pointing them way from us while pressuring the octopus.

I've seen a gauge face pop once, it fluttered away without any apparent risk or even a significant disturbance. Was from the '70's. Also seen a button gauge face fail, once again, fairly gentle explosion and would seem horribly unlikely to be hurt by. (intentional irony in gentle explosion, the plastic face flew a couple feet)

Why are we traumatizing new divers with this titbit of task loading? Anyone seen one or read of one going off in a way that might cause injury...

• northernone
• Replies: 62
• Forum: Advanced Scuba

A fun read. If you still have all your fingers.

 

[Belzelbub]

We were also once told to back valves off a turn and a lot of other nonsense.

True, but as I understood it, the 1/4 turn back was once a good idea due to the valve designs of the day. Not required on modern valves, but some are still taught and do that to this day. I probably did this after my first course, but it was probably not required then either. Haven't done it since.

The lens is either plexiglass or tempered glass and there is a blow out plug in the case. I do not think we need to fabricate reasons to switch to an AI computer.

True. However, whether there is a real need or not, doesn't change what's taught. I was definitely taught to turn the spg away from faces, and to open the valve slowly. Probably not so much of a real issue anymore, but it's a practice that doesn't really have a downside. It doesn't hurt anyone to face away from people's faces. Probably just want to make sure that the blowout plug isn't pointed at anyone's face either.

 

[LI-er]

True, but as I understood it, the 1/4 turn back was once a good idea due to the valve designs of the day.

Still a good idea. Most dive charters are going to check your valve before you splash. If you cut the valve back a quarter turn the person who turns it knows it's definitely on when it twists open that last little bit. If it's all the way open they really gotta give it a twist to make sure it's not firmly closed. Makes their job easier and repetitive attempts to twist an already valve open even more isn't going to do it any good.

 

[Nemrod]

True, but as I understood it, the 1/4 turn back was once a good idea due to the valve designs of the day. Not required on modern valves, but some are still taught and do that to this day. I probably did this after my first course, but it was probably not required then either. Haven't done it since.

Basic valve design has not changed and there is no reason then or now to back it off, of course I was taught the same thing. It just causes confusion. I still, usually, back mine off. Force of habit, I cannot stop myself, I just do it automatically. I just hear my instructors long gone voice, Jimmy, turn the valve on like this and then turn it back a half turn, now give me ten (pushups). My OCD is not quieted until I have done so, my universe is not right until , because my instructor 56 plus years ago said so.

In 1966 we did not have SPGs, at least I had never seen one nor did we use them in the course, we all had J rods. In 1970 when I took my advanced course, we did have SPGs and I was taught to turn it away from my face as you were, same instructor, now Jimmy, drop and give me ten! Again, the lenses are Plexi or tempered glass and there is a pressure relief plug built into the case. I certainly would not put it right up to my eyeball when turning on air but an SPG is not going to explode and send shrapnel all over.

If a DM or deck person lifts a tank by the AI transmitter is it going to blow off and put a 90 caliber hole in something? I need to start that urban legend. Those little screws in the side of the AI case look awfully little and do they have a blow out plug?