Vang

A line or tackle system used to control the angle of a boom on a sailing vessel, preventing it from lifting and stabilising the sail.

The vang, also known as a boom vang, is an essential piece of rigging on a sailboat that helps manage the shape and performance of the mainsail. It typically consists of a block and tackle system or a hydraulic piston that runs from the base of the mast to the underside of the boom. Its primary function is to apply downward force on the boom, preventing it from rising when the mainsail is under load, especially when sailing downwind. Without a vang, the boom would lift, causing the sail to lose its optimal shape, which would reduce the boat’s speed and efficiency. By pulling the boom down, the vang flattens the sail, reducing drag and allowing for better control of the sail’s power. 

In addition to controlling sail shape, the vang also plays a critical role in safety. When sailing in strong winds, an uncontrolled boom can swing dangerously, posing a risk to crew members. The vang helps keep the boom stable, reducing the chances of accidental injury. On modern yachts, the vang may be adjustable from the cockpit, allowing for easier and safer sail trimming.