Double Whip Tackle or Double whip technique. A mechanical advantage system....
My question Todd, when cutting the base, how did he go about it? Was all of the tension still in the system and did he face cut it or was it a straight directional cut. From your description, it sound like it was pretensioned and pretty exciting when it finally moved. Good thing, from the pictures, the structure was already severely damaged no? What was the red rigging line you guys used? As always, impressive.