Originally Posted by nolatom
A vang by definition is rigged on the same pivot point as the boom/gooseneck, so as to keep a steady tension on the leech no matter whether you trim or ease the mainsheet.
In my experience, the block system that goes from the boom to the base of the mast (a lot of modern boats use a block system in tandem with a sprung telescope or hydraulic rams) to control tension of the leech is called a kicker and is not the same thing as a vang.
A vang is
a preventer and is connected between the boom and the rail when running off the wind. The kicker stops the boom from lifting when the main sheet is eased but the vang holds the boom to the side to "prevent" crash jibes.
Billyruffn, your system is very rare. I can't recall ever seeing one like that. How would one experience an "accidental jibe" with this system connected?