Incident Report

2009-04-03Divers A (novice) and diver B (trained) made a series of dives in a mine commonly used for training. On the final dive diver A experienced a sudden increase in bouyancy and found himself trapped on the ceiling in approx 1/2 a metre of water. Up until this point the diver had demonstrated good bouyancy and trim. Diver B had stopped to watch diver A negotiate a minor restriction in the passage and was on hand to give assistance. A large amount of air was collected around diver As buttocks and they were unable to migrate it towards the shoulder dump. Diver B disconnected the drysuit feed. Great difficulty was experienced in freeing diver A and diver B was considering slashing the drysuit to release air. However the use of a boulder for extra ballast returned proper bouyancy and diver A was lead approx 50m to safety. Diver B then returned along the line to collect his pegs and observed that the crystal clear visibility had in places been reduced to zero by the incident. Whilst the air consumption of both divers had increased dramatically during the incident both had ample supplies of air. However increased task loading caused Diver A to breathe off only one air supply during the incident reaching dive base with 100 bar in one cylinder and only 30 bar in the other. Despite this being one of Diver As firstOverhead Environment dives he remained composed and rational throughout the incident. Upon inspection it was discovered that diver As drysuit inflator contained small grains of sand causing it to stick open and overinflate the suit. Also the shoulder dump was fitted over the bicep rather than the side of the arm or tricep making it harder to dump air.Carry out regular equipment maintenance and inspect it thoroughly prior to diving. Plan to carry ample reserves of air. Had gas management for this dive been calculated strictly to rule of thirds it may well have ended in fatality. Expect and train for increased task loading. Remain composed - dont Panic!