A Chod Rig is basically similar to a helicopter rig. Essentially used for fishing in silt.
Normally a short hooklength is semi-fixed in place with rubber beads and float stops outside of these so that it can be adjusted according to the depth of the silt.
A large ring swivel provides the rotary action. I believe it is better using a short stiff hooklength which as we know, provide excellent anit-eject properties.