a system used to hold the boom down, particularly when boat is sailing downwind, so that the mainsail area facing the wind is kept to a maximum. Frequently extends from the boom to a location near the base of the mast. Usually tackle-or-lever-operated.
sail control that lets a sailor move the boom up or down during a reach or run. The boom vang, sometimes just called the vang, also controls mainsail shape when the mainsheet is let out enough that it no longer pulls the boom down.
A tackle used to pull the boom down in order to control the shape of the sail and movement of the boom.
an adjustable connection between the boom and the base of the mast which holds the boom down in addition to (and independent of) the main sheet. Its primary function is to control the twist in the leech of the mainsail when sailing on reaches and runs, when the boom is no longer positioned above the traveler track. In some circumstances the vang is used to bend the mast, therefore flatten the main when sailing up wind. It is most commonly a block and tackle system, but hydraulic systems and rigid systems are also available which may hold the boom up as well as pull it down.
a line that adjusts downward tension on the boom
A boom vang is a line or piston system on a sailboat used to exert downward force on the boom and thus control the shape of the sail. In British English, it is known as a "kicking strap". An older term is "martingale".
