dive computers and reverse profiles

[dmaziuk]

Maybe they shouldn't touch it? Food for thought.

Maybe they shouldn't, but they do. Maybe I shouldn't turn the valve back off after setting everything up and checking the SPG, but when there's 40 more minutes to wait before the splash, I often do. This is why you take a couple of deep breaths watching the SPG before you splash -- but you knew this already.

 

[wetb4igetinthewater]

Maybe they shouldn't, but they do. Maybe I shouldn't turn the valve back off after setting everything up and checking the SPG, but when there's 40 more minutes to wait before the splash, I often do. This is why you take a couple of deep breaths watching the SPG before you splash -- but you knew this already.

As I stated earlier, the cylinder has to be no more than cracked open for me to make the needle move. I don't think that is a useful test except for if the valve is closed. If someone can make their needle move with a quarter turn open, great. I never have been able to.

I dive sidemount, so no deckhand is going to reach under my armpits to open my valves. When I still dove backmount, I made sure to keep an eye on deckhands/DMs when I went from my seat to off the boat to ensure they didn't touch my valves. One time one did, and I returned back to my seat, removed my kit to check. I made sure to make a point to not touch my gear.

 

[dmaziuk]

As I stated earlier, the cylinder has to be no more than cracked open for me to make the needle move. I don't think that is a useful test except for if the valve is closed.

So when everyone is taught to do this (and does), and every DM and deckhand is taught to not touch other people's valve unless they say "my needle moved, could you check my valve" (and they all do), the world will be perfect.

 

[EFX]

This does leave me with one disturbing thought though. If you can't count on someone to know which way to turn a valve, they should not be checking anybody's equipment. A nitwit that doesn't know which way a valve gets turned can change it from fully on to fully off the same way that they can change it from almost fully on to almost fully off.

I was on a dive charter, on a fairly big boat, about 14 of us if I remember correctly. I assembled my own equipment and it is my standard practice to turn the valve on fully open (no 1/4 turn back) and breathe through each reg while observing the SPG. Once I'm done I leave the valve open for the entire trip out to the dive site. I was standing up and as we approached the dive site one of the DM's was frantically going tank to tank turning on everyone's air. I checked my tank and found the valve turned completely off. Apparently the DM wasn't thinking about the direction of the valve but assumed no one had turned their air on. So, it can happen by fully qualified people. The moral of the story: always check to be sure your air is on just before kitting up, and if one of the crew approaches you make sure they don't touch your equipment.

 

[wetb4igetinthewater]

I was on a dive charter, on a fairly big boat, about 14 of us if I remember correctly. I assembled my own equipment and it is my standard practice to turn the valve on fully open (no 1/4 turn back) and breathe through each reg while observing the SPG. Once I'm done I leave the valve open for the entire trip out to the dive site. I was standing up and as we approached the dive site one of the DM's was frantically going tank to tank turning on everyone's air. I checked my tank and found the valve turned completely off. Apparently the DM wasn't thinking about the direction of the valve but assumed no one had turned their air on. So, it can happen by fully qualified people. The moral of the story: always check to be sure your air is on just before kitting up, and if one of the crew approaches you make sure they don't touch your equipment.

I’m thinking of getting big stickers made that say “DON’T TOUCH MY F%@KING VALVES!

That works for my cylinders, but not on vacation. I’ll think of something

 

[Esprise Me]

EDIT: By the way, it seems like these valve indicator knobs would more or less solve this problem. Do people use these things?
View attachment 582130

I do. Love mine. But it doesn't help much when I travel.

 

[tbone1004]

I’m thinking of getting big stickers made that say “DON’T TOUCH MY F%@KING VALVES!

That works for my cylinders, but not on vacation. I’ll think of something

 

[scubadada]

I was on a dive charter, on a fairly big boat, about 14 of us if I remember correctly. I assembled my own equipment and it is my standard practice to turn the valve on fully open (no 1/4 turn back) and breathe through each reg while observing the SPG. Once I'm done I leave the valve open for the entire trip out to the dive site. I was standing up and as we approached the dive site one of the DM's was frantically going tank to tank turning on everyone's air. I checked my tank and found the valve turned completely off. Apparently the DM wasn't thinking about the direction of the valve but assumed no one had turned their air on. So, it can happen by fully qualified people. The moral of the story: always check to be sure your air is on just before kitting up, and if one of the crew approaches you make sure they don't touch your equipment.

Sometimes a crew member will even sneak up on you from behind and check your valve, after you're standing, getting ready to go. Last thing I do before jumping is to breathe off my reg and watch my SPG. I made this a habit long ago and do not forget it

 

[pauldw]

@dmaziukRGBM-disproven by current research, don't use it

Someone help me with this. Assume I'm a rec diver. And assume I don't know anything. But wait, I repeat myself. Anyway, does this reflect DIR/cave divers predilections for thinking their brains are smarter than computers, or is there a genuine reason why I should throw away my Suunto Fused RGBM 2 using Eon Core?

 

[tbone1004]

Someone help me with this. Assume I'm a rec diver. And assume I don't know anything. But wait, I repeat myself. Anyway, does this reflect DIR/cave divers predilections for thinking their brains are smarter than computers, or is there a genuine reason why I should throw away my Suunto Fused RGBM 2 using Eon Core?

As mentioned, the leading researchers in decompression theory have essentially said that the theory behind bubble models is not in line with the current state of the art in decompression. The Spisni study was DIR divers thinking their brains were smarter than computers, they were proven wrong. The researchers have come out saying that even the Shearwater default of 30/70 for gradient factors has a GF-Lo that is far too low for optimal decompression.
If you're doing NDL diving it really doesn't matter, but if you're doing dives where the bubble models have you prioritizing deep stops, well, there is a reason no real technical diving is done with Suunto computers.