mainsail boom control running rigging
I looked at a boat today that had a triangular type mainsail boom sheet rigging. There was a block at the rear starboard side of the cockpit, an block at the end of the mainsail boom, and a block and cam cleat at the port side of the cockpit at the rear. What is this called and how does it work? I didn't see the boat rigged so I don't know what it really looks like.