For flatfish and whiting etc at range
A one up one down medium distance rig
A general rig that is particularly effective at slack water
For scratching at close to medium distance with a long trace body and high top dropper or droppers
The principal behind this rig is that of mini-pulley rigs and provide less resistance to the biting fish.
A general purpose rough ground rig
Ian Golds has been credited as one of the originators of this rig which allows long snoods to be used where the bottom hook falls to the seabed.
The weight at the top of the trace helps keep all hooks tight on the bottom. Used in Netherlands and Belgium from the boat and shore
The principal behind this rig is that when a hooked fish is being retrieved the weight of the fish will cause the free running tubing to act as a pulley.
For scratching at close to medium distance, because the construction of this rig involves overhand knots it is not suitable for power casting