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Web Monkey:It beats the heck out of the other method, which is to attach a liftbag, add air until the object breaks free of the bottom, then goes hurtling towards the surface, only to come unhooked, fall back down and kill you.
Terry
Rick Murchison:Uh, doing it (a free lift at neutral buoyancy) right and safely takes a little practice and technique, but it ain't exactly rocket science either...
Rick
(photo credit - Tom Smedley)
You're going to apply more lift than it weighs to get it free? Hmmm.... interesting. I suppose if you can't free it any other way then the limited (and complicated) 10' per lift makes sense. I may use some lift to assist in freeing an object, but (so far) never more than it weighs - less lifting and more digging.Web Monkey:That depends on how deeply the object is embeddded in the botttom, and the bottom type.
If it's stuck in the mud or is buried to any significant depth, it takes a lot more lift to get it free from the bottom than is required to make it neutral.
Terry
Been there done that, but isntead of a series of 10' loops, all it takes is one big tug to get the thing free (with a tool is preferable, but use a big bag if not), then you dump all the air from the bag, let it settlg on the bottom, and start a normal lift.Rick Murchison:You're going to apply more lift than it weighs to get it free?
FWIW, I do not recommend this method.pants!:one big tug to get the thing free (with a tool is preferable, but use a big bag if not), then you dump all the air from the bag, let it settlg on the bottom, and start a normal lift.
Care to elaborate?Rick Murchison:FWIW, I do not recommend this method.
Rick
Sure.pants!:Care to elaborate?
The Kraken:I absolutely refuse to disclose how I know this or who the divers are, but I know two guys who used a government surplus duffel bag and a large garbage bag to effect a lift once upon a time.
It was interesting, to say the least.
The K