I stumbled across this and wonder what all y'all have to say about it. I look back upon my training and wonder if all those bottle movements and unclippings-reclippings were necessary, or whether I could Keep It Simpler. I got it from here: 2nd gas switch « Tec Diving Indonesia
"2nd gas switch
There has been some debate among even experienced instructors at the T50 or TDI Extended Range level as to whether a diver should switch from the first deco gas to back gas before switching to the second deco gas. Following our philosophy of “learn it once and use it always,” we prefer to switch directly to the second deco gas as switching to back gas during decompression is problematic with regard to DCS risk on deeper trimix dives.
The switch procedure is all the same until it comes time to actually switch the regulators and route the deco hose. Once you have gone through the entire switch procedure and your teammates have confirmed your second deco gas, go ahead and remove the first deco reg with the palm of your left hand, pulling it up over your head and in front of you to the left. You may then route the second deco reg with your right hand around the back of your neck and into your mouth.
Failure to follow these simple steps commonly results in tangled deco hoses, a confused team, and a diver ending up wondering up which deco reg is which after trying to untangle them. All of this unnecessarily delays the team’s initiation of the 6m decompression.
Once the backup computer is updated (if one is used), go ahead and stow the first deco regulator under the top retaining band on its tank.
Whether to shift the top (21m) deco tank below the top one is another matter of debate. As the 6m gas is the last gas I will be breathing (airbreaks aside) until the end of decompression, and as the 21m gas is still my next most viable deco gas, I prefer to leave them. I see no reason to move them, especially if I am decompressing in the blue and don’t want to risk dropping the 21m bottle during the shuffle.
Furthermore, in dives which require 3 or more deco switches, we switch from the top tank to the bottom tank at the second switch. This switch is then followed by a shuffle involving the leash where the top tank is moved back and a new tank is moved into place under the current decompression tank in use. In no instance is a tank moved from the top to the bottom just for the sake of moving it from the top to bottom. It seems unnecessary to me."
Thoughts in response? Most of my diving involves a single cylinder and is within NDLs. Most of my technical diving involves only one deco gas. I haven't used two deco gases for more than a year. I haven't used a travel mix or third deco gas since my advanced trimix course.
"2nd gas switch
There has been some debate among even experienced instructors at the T50 or TDI Extended Range level as to whether a diver should switch from the first deco gas to back gas before switching to the second deco gas. Following our philosophy of “learn it once and use it always,” we prefer to switch directly to the second deco gas as switching to back gas during decompression is problematic with regard to DCS risk on deeper trimix dives.
The switch procedure is all the same until it comes time to actually switch the regulators and route the deco hose. Once you have gone through the entire switch procedure and your teammates have confirmed your second deco gas, go ahead and remove the first deco reg with the palm of your left hand, pulling it up over your head and in front of you to the left. You may then route the second deco reg with your right hand around the back of your neck and into your mouth.
Failure to follow these simple steps commonly results in tangled deco hoses, a confused team, and a diver ending up wondering up which deco reg is which after trying to untangle them. All of this unnecessarily delays the team’s initiation of the 6m decompression.
Once the backup computer is updated (if one is used), go ahead and stow the first deco regulator under the top retaining band on its tank.
Whether to shift the top (21m) deco tank below the top one is another matter of debate. As the 6m gas is the last gas I will be breathing (airbreaks aside) until the end of decompression, and as the 21m gas is still my next most viable deco gas, I prefer to leave them. I see no reason to move them, especially if I am decompressing in the blue and don’t want to risk dropping the 21m bottle during the shuffle.
Furthermore, in dives which require 3 or more deco switches, we switch from the top tank to the bottom tank at the second switch. This switch is then followed by a shuffle involving the leash where the top tank is moved back and a new tank is moved into place under the current decompression tank in use. In no instance is a tank moved from the top to the bottom just for the sake of moving it from the top to bottom. It seems unnecessary to me."
Thoughts in response? Most of my diving involves a single cylinder and is within NDLs. Most of my technical diving involves only one deco gas. I haven't used two deco gases for more than a year. I haven't used a travel mix or third deco gas since my advanced trimix course.
