I don't think there is any bungie running through the boom. There should be a saddle foward of the outhaul car system and the bungie simply loops between the saddle and the car. This is a big time zoomed and cropped image. The black line above the boom is the bungie. Along the boom is the outhaul control line. From the forward clamcleat it runs back and around a block, returning forward to a tie off point. A line tied to this block runs aft around a turning block up through the car and down to the other side of the boom where it is secured.