Not sure worth to post, no one injured an no any consequences but might make sense for experience exchange. Koh Lipe, Thai, this weekend, 8 miles rock dive site. Very poor visibility (~3-5m) and ripping current. Group of may be 7 divers and 2 local dive guides. mixed group with 12/15 L tanks, air. Less than 20 m depth. At the end of the dive on the mooring line about 4-5 m depth 2 divers went out of air having only 1 dive guide as reserve air source. So, as I was one of that divers here is the situation how I saw it. Pre dive briefing, good and detailed, discussed that 70 Bar - sign to return to mooring line and ascend. So I (12L tank) and another diver (15l tank) were assigned to one dive guide, other 4 dove with second dive guide. Dive was awful (my point of view) useless fight with current in poor visibility, but finally we went to some rock we could anchor and see some big fishes playing around the corner. During routine air check I and other diver from different group showed 70 bar so we were told follow one of the dive guide (local Thai, might 50-60 kg weight) as it was discussed during briefing. Guide swim first, after him second diver and after him I. I can see only bubbles from guide and silhouette of second diver. We went straight against current so half of time I cling to rocks instead finning to save air. This back trip took a little bit long than I supposed, so I discovered I got 30 bars and no any signs of mooring line. So I decided to ascend separately and went upper got my DSMB and prepare to deploy it. Where was no chance warn guide due to he was far forward to notice any signs. During ascend preparation I noticed mooring line and buddy with guide hanging on it. My error number 1 - I decided to join them due to risk of being drag away from boat by current (this is open see dive site 25 mins from Koh LIpe on speed boat). So I descended and grab mooring line down to guide just under him. At this moment I discovered that I have less than 10 bar (around 0). So I catch guide reserve 2 stage (it just hand from his regs in front of me) and start breathing from it. My error #2 - I did not warn clearly guide that I am on his reserve. At this moment I saw guide started to seek his reserve regs very actively I would say... I understood that second diver got out of air too, and due to our depth was about 4-5 meters and no any deco obligations were collected decided that I can do emergency ascend, so I gave guide reserve to guide (just put it in his hang, cause he were trying to find reg by hand looking up to second diver, and switched back to my tank. Gauge was on zero. At this moment diver from other group went down near mooring line asking our guide "is all ok" and our guide answered "all ok", so those diver went down despite my attempts to signaling that I am out of air - obviously he just thought that all ok as guide showed him. So I let mooring line go and spent rest of air to inflate wing and did emergency ascend (4-5 m depth). On surface gauge was below zero. Within couple of minutes guide and second diver ascended. No any consequences was for all of us (despite safety stop protocol were omitted, but as I mentioned with GF 85/90 my computer did not show any deco obligations - I use OSTC tec version for recreational dives too). It was interesting though, that I asked dive guide for debrief after dive (no any complains or blaming from my side, i consider that every one solely responsible for his own life) cause I think this situation worth to speak through but actually got only one feedback from guide "I am so sorry, please forgive me, it is my mistake". And more interesting that no one from dive center senior stuff or course instructors showed no any sign of willingness to discuss it. I am not going name DC cause in this situation big portion of errors are my own errors, but I think it worth to describe. After dive I calculated SAC for this event and actually, I usually have 14-16, but this time it was 30. And it is fancy but in next day for site with similar condition (string current) dive group were consist of thai dive guide (half my size), guy with 15L (all other have 12L), nice little girl might 50 kg max and me... 198cm height and 130 kg weight... But dive was good, nothing happens 
P.S.
Actually, during debriefing dive guide mentioned that he lost direction to mooring line and it took surprisingly long to find it. And obviously he has no idea about differences in our SAC rate in strong current.
P.S.
Actually, during debriefing dive guide mentioned that he lost direction to mooring line and it took surprisingly long to find it. And obviously he has no idea about differences in our SAC rate in strong current.
