A must on any boat, large or small, boom vangs are primarily used to control the leech of the mainsail by restraining the boom from rising when sailing. This helps eliminate excessive sail twist which when left uncontrolled can make your boat unstable with an increased tendency to roll in waves. Investment cast snap shackles (on all models but our 35-20) offer quick and exacting placement of the tackle allowing the system to be moved to the toe rail for use as a preventer. This arrangement "prevents" the booom from swinging back into the boat in light air and also helps avoid accidental gybes in heavy air. All of our boom vang kits feature Dacron yacht braid appropriate for the size of the boat.