Lift Bag Usage

[Web Monkey]

This may be a technique more appropriate for my location (Great Lakes), where the isn't usually too much current, but almost everything is buried in the mud.

Terry

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.
In many of the places we recover stuff (the Gulf of Mexico) current is often a major factor, and running a line all the way to the surface would introduce a horizontal dynamic into the problem we may consider more risky than a little overestimation on the lift required to assist in freeing an object. I'll keep your method in mind, though, for that time we may need it
Rick

 

[captndale]

Why use a lift bag for a 40 puond object? The easier way to get it up is just to tie a bouyed line to it and haul it up from the surface. Take a line somewhat longer than the water depth (longer if there is current); tie a buoy (plastic jug or fender to the end; swim down and tie the other end to your prize; go back up and fish the buoy out with a boat hook and pull it up.