Shown here is the outhaul line exiting the boom (on the left), wrapped around a winch, and tied off on the cleat on the right. (The end of the boom is out of the picture to the left.) A winch is needed on moderate to large sailboats to exert enough tension on the foot of a large mainsail. The tighter the outhaul is pulled, the flatter the bottom of the sail becomes. The looser the outhaul, the fuller the sail.
How to Adjust the Outhaul
The principle for adjusting the outhaul is similar to that for using a boom vang in light and moderate wind.
- In light wind, the outhaul should be fairly loose, allowing the mainsail to be fuller. Wrinkles may form along the foot of the sail.
- In moderate wind, the outhaul should be moderately tight, flattening the sail and giving better shape for sailing upwind or on a reach.
- In a stronger wind, when you might need to depower the main to prevent excessive heeling, the outhaul should be very tight. A flatter sail produces less heeling force.
