Incident Report

2006-01-10Whilst digging in the main feeder of Far Sump I have had several instances of problems with gravel entering the mouthpiece of my regulators. The gravel here is mainly angular chert fragments which aren\'t like the more usual pea gravel which causes problems. I use Poseidon Cyclon 300 regulators and this angular cherty material has on occasions prevented the 2nd stage operating lever from moving leading to no air being delivered at all. (Normally the only problem gravel causes is water ingress through the exhaust diaphragm.)Many cave divers deal with the wet breathe problem caused by occasional gravel fouling by disassembling the 2nd stage diaphragm housing whilst underwater to remove the offending gravel. In this particular site the frequency of fouling is so great that stripdowns arent a good enough solution. I have made a plug which fits into a Poseidon mouthpiece which is attached by a short cord to the neckstrap and which is inserted into the 2nd stage mouthpiece which is not being breathered from to seal it against gravel ingress. This does work but is occasionally dislodged. So I may go back to the old trick of placing nylon mesh over the mouthpiece orifice to stop gravel getting in. This latter method is effective but does interfere a bit with the breathing characteristics of the regulator. Fortunately this site is only shallow so its not too important.