Yes, a Jersey Upline is a Yankee thing...specifically a Jersey thing that wreck divers in New Jersey came up with. It's basically a piece of safety gear. It looks like a long thin reel with handles at both ends. Most divers make their own. They wind biodegradable line onto the reel (sisal I think) and tie a lift bag to the end of the line. It is traditionally attached to the back of their doubles, out of the way, with thin pieces of inner tube so it can easily be removed.
It is used as an emergency anchor line if needed. Put a little air into the lift bag and hold onto the handles as the bag surfaces, then follow the line up as deco stops are completed. Once the diver surfaces s/he cuts the line and let's it drop to the bottom, folds up the lift bag and swims back to the boat.
Good description......but it is worth noting that this piece of gear so widely used not so many years back has mainly been replaced by modern quality reels for wreck diving.