The following images were provided by Starling Gunn who sails FS 1104. Starling installed an underdeck purchase system on his boom-vang that generates a 12:1 purchase ration. It would not be difficult to convert this system to allow additional purchase.


These first two images show how the vang yoke attaches to a line fixed to the boom. A single block is attached to a line of fixed length that connects to the boom. The vang yoke is fixed to the starboard side of the mast support, runs up through the turning block and back down to another turning block mounted on the port side of the mast support.
	This is a close up showing how the turning block is mounted to the mast support.
	Here is an overview of how the yoke connects to the purchase system that is mounted under the foredeck.
	The double block attaches on the keel toward the bow of the boat. Starling normally has a bow flotation bag in his boat - it has been temporarily removed.

Here is some detailed descriptions of what the hardware under the deck does and where it goes.
	The system that doubles the purchase from under the deck now must be run up to some type of control.
	Starling uses a Waco 360 to provide easy access to the 12:1 boom vang.
	If you would like to use your Waco 360 for some other control use, you may want to consider this method of securing the vang tension.

Your ideas are always welcome, send them to Fields C. Gunsett and I will get them loaded.