I have just been informed of a mis-hap which occured on a dive vessel in the last week or so. It involved a lift-bag (2 ton I believe) and it prompted me to drop a few hints on the usage of these 'ornery critters'.
When installing a bag be sure that the rigging used is man-enough for the weight of a fully inflated bag - ie, it's no use rigging a load with a 3 ton sling and then shackling a 5 ton bag to it - even if you only intend to put 2 tons of wind in it. Check to make sure every item of rigging is suitable; slings, shackles etc. Ensue also that the bag has a suitable 'tripline' originating from the top webbing and that it's long enough to extend the length of the bag plus rigging and can be secured to a strong-point. Before giving the bag some 'wellie' with the airline first give it just enough guff to stand up. You can then give it the once-over to make sure everything is secure, that shackles are the right way round, there's no twists or knots in the rigging and that your rigging isn't frayed/damaged or running across any sharp edges that could cause a failure. This is also the time to check the bag for leaks - the most frequent leak is because you haven't noticed the dump valve is in the 'open' position
. Once you're happy that the bag and your rigging is 100% you can go ahead and fill 'er-up!
Treat lift bags with respect, a rogue 1 tonner could take you for a nasty ride to the surface. Believe me, the respect will come when you have a few 10 ton bags filled to capacity lurking around you, you take real care where your umbilical runs - you can hit their straps with a hammer and there's no give!
Stay safe,
Berko
