Air share

[Angelo Farina]

"Roll Off" is possible for the left post on a twin set. If you let the hand-wheel in contact with any hard object eg the roof of a cave. The forward movement will eventually shut off the valve! Rubber hand wheel is the worst.

Cannot remember which tec agency actually recommended the long hose attached to the left post so "roll off" would be immediately noticed by the diver. Long time ago.

My reg was in the central post, not in the left one. The twin tank was a Technisub, like this one, with the safety reserve /(which you cannot pull by error before it engages):

 

[divinh]

First it was me when I was doing my OW. It was towards the end of the dive and I was getting near 500psi but I wasn’t worried because by the end of this dive we were pretty shallow. I signaled to my instructor on how much air I had left and in my opinion she freaked out. Made me take her octo, deployed the dsmb and after a safety stop she signaled for me to surface and get on the boat. Not long after everyone else joined me.

I'd be curious what the hand signal you used was and if she checked your SPG before handing over her octo.

 

[divinh]

I shared air with the guide in Fakarava, French Polynesia. There was four of us, the guide, myself and a couple who were former DM's. We dropped into the blue of Garuae Pass. We proceeded down to 27m and drifted our way up to 13m to get over a reef lip, then down to 20-22m for about 15 min. Just after the 13m, she checked everyone's air and decided I needed to be on her octo, as she knew we would go into mandatory deco; that was in the dive plan. At some point in the 15 min, I switched back to my primary. We finished off the dive with a 15 min stop at 5m. I had 50 bar at the end. Total dive time was 60 min.

 

[happy-diver]

My reg was in the central post, not in the left one. The twin tank was a Technisub, like this one, with the safety reserve /(which you cannot pull by error before it engages):
View attachment 658268

This equipment is most beautiful

 

[Raphus]

I shared air with the guide in Fakarava, French Polynesia. There was four of us, the guide, myself and a couple who were former DM's. We dropped into the blue of Garuae Pass. We proceeded down to 27m and drifted our way up to 13m to get over a reef lip, then down to 20-22m for about 15 min. Just after the 13m, she checked everyone's air and decided I needed to be on her octo, as she knew we would go into mandatory deco; that was in the dive plan. At some point in the 15 min, I switched back to my primary. We finished off the dive with a 15 min stop at 5m. I had 50 bar at the end. Total dive time was 60 min.

That's a bit shocking.
"A planned deco" with not enough gas.
Just saying:"I go in to deco" is not really planned deco.

Were you on single tank, or had equipment failure?

 

[Centrals]

My reg was in the central post, not in the left one. The twin tank was a Technisub, like this one, with the safety reserve /(which you cannot pull by error before it engages):
View attachment 658268

You tank valve hit the roof several times and shut off the gas supply.
It was still a "roll off" albeit completely different from that caused by the forward movement of the diver.

 

[divinh]

That's a bit shocking.
"A planned deco" with not enough gas.
Just saying:"I go in to deco" is not really planned deco.

Were you on single tank, or had equipment failure?

We were all on single tank. 200+ bar at the start of the dive. The determination to share air with the guide happened around 100 bar. I was the least experienced of the four of us and no doubt was consuming air at a faster rate, which I think led to the decision to share air, so I could do the stop on my own tank at the end of the dive. We started the mandatory deco stop when anyone one of us incurred 5 min over NDL, so we did 15 min at 5m and made sure everyone's computers cleared.

I don't know how much air everyone else had, but finishing with 50 bar makes me think that if I had to sit at 5m for longer, it wouldn't be a problem.

 

[Raphus]

We were all on single tank. 200+ bar at the start of the dive. The determination to share air with the guide happened around 100 bar. I was the least experienced of the four of us and no doubt was consuming air at a faster rate, which I think led to the decision to share air, so I could do the stop on my own tank at the end of the dive. We started the mandatory deco stop when anyone one of us incurred 5 min over NDL, so we did 15 min at 5m and made sure everyone's computers cleared.

I don't know how much air everyone else had, but finishing with 50 bar makes me think that if I had to sit at 5m for longer, it wouldn't be a problem.

OK. Personally I would consider air sharing during a deco dive as an accident. Which luckily doesn't cause any harm.

But if the DM could not share gas then you would not have enough to finish the deco.
Just recently there was a accident here, where exactly this happened.
"planned deco" on single tank, not enough gas to share and one got bent badly.

I am not an expert or trained in tech diving yet, that's just my personal opinion.

 

[ginti]

OK. Personally I would consider air sharing during a deco dive as an accident. Which luckily doesn't cause any harm.

But if the DM could not share gas then you would not have enough to finish the deco.
Just recently there was a accident here, where exactly this happened.
"planned deco" on single tank, not enough gas to share and one got bent badly.

I am not an expert or trained in tech diving yet, that's just my personal opinion.

I personally have the same view of you.

Could you send me the link to the accident you are speaking about? I cannot find it... thanks

 

[Centrals]

As a tec diver for over 20 yrs I am speechless when someone would agree with such a ridiculous dive plan and went along at the end!
A "trust me" dive like that can turn pretty bad in no time at all.