the ultimate power source
for vang/kicker and jib halyard tension
illustrated in photos of W10888, a new Hartley Mark IV

Below you will find photos of cascade systems, which - if you don't already have something else installed - are pretty universally seen as the best and cheapest way to achieve tension on your jib halyard and your kicker (boom vang).

The vang lines (sort of orange) end up leading aft along each side of the centreboard box
before running out under the thwart to cleats at the side.  click here for larger image

click here for larger image

Here Peter Rahn is holding the hook that goes into the eye splice in the jib halyard. Note also one of the vang line cleats on the thwart at the bottom right-hand corner of this pic. 
click here for larger image