Incident Report

2016-02-04The diver entered the system heading upstream following the existing line carrying a reel for the possibility of extension at the far end. The cave was logged as silty in old dive reports and it was visbility was soon zero despite heading upstream since the line had to be removed from the silt ahead of the diver it was also very loose and unbelayed. There was one line other than the main one (all thin 2-3mm) but it wasn\'t seen to be attached even after good investigation - although possibly buried in silt. The turn was made here as a silt bank was seen ahead of the divers\' looming silt cloud still above thirds the diver started his exit from what he thought was far into Sump 3. After a significant period (slower going due to pitch black vis on exit) the divers line reel caught in the main line. The diver was very meticulous with line management during the incident maintaining contact with the line and when switching hands noting the direction of thumb being either in or out. Still after the incident and continuing in airspace was gained in an unrecognised airbell not the expected one between Sump 2 and 3. Diving on 3\'s getting too lost was not an affordable mistake. The diver had to make a decision and decided to continue on the assumption that this air bell must have been missed on the way in. The diver then found themselves during a small improvement in visibility at their original turn point near the junction. The diver jettisoned the floaty reel as it was a small hindrance and headed back to the previous airbell. The diver did not know for sure what had gone wrong and did not know for sure if this airbell was on the route out or whether a junction had been totally missed (with numb hands and neoprene the connection between bits of line at the one drop weight belay in zero vis was complicated to navigate due to silt and line thickness). The diver made the commitment to continue back the way he thought was out back through the unknown airbell (which turned out to be the sump 3-4 airbell) assuming it had been missed going in and out and had only found it when coming back in again (the line does not surface) and that during the line reel issue earlier they had made an accidental U turn. The diver could afford no more mistakes and the air bell was not seen to be safe to breathe for an extended period due to size. The diver carried on and found his way to the Sump 2-3 airbell and exited uneventfully from there to much relief.The initial cause of the problem was a positively buoyant line reel and loosely laid unbelayed line all in absolute zero vis. Buoyant line reels are not ideal. The diver has thought much about his line management since the incident and has isolated a potential cause for reversing his direction of travel since the line management was deliberately meticulous at the time due to conditions. In the darkness the switching of hands on the line was attributed to athumb direction thumb initially facing out towards exit. When the hands were switched thumb to thumb the thumb was then facing back in and the diver knew this. Once the issue was sorted the diver then switched hands back hands opposing on the line to alignthumb out feeling the line off the left hand as best he could the whole time. It is thought that a combination of movement within the passage (silt floor so hard reference) and the fact that the line was loose likely ended up with the line going under the palm over the thumb and through the hand and over the top of the fingers (an S bend) led the diver to not detect this when feeling for the continuation of the line from the hand. In this case when the diver thought he had swapped his right hand back to the line with thumb out the thumb was facing in and the line was followed as such. The very thin line cold hands and neoprene were major contributors. In future similar situations when the diver is not confident that touch alone is enough to ensure that the line is coming straight out of the hand and reference and visibility is absolute zero he will endeavour to use the following solution: - On first noticing an issue immediately place snap-bolt or karabiner or similar on the line in front of them in theout direction. Once the issue is solved if the diver does not find the aforementioned clipped on item within reasonable time they are likely to be going the wrong way. In a situation where visibility exists even slightly a compass bearing may instead be taken - not possible in this case (plus the divers compass was smashed open during a restriction further back into the cave - unbeknown to them).