Sail foot

The sail foot is the bottom edge of a sail, running between the tack (forward lower corner) and the clew (aft lower corner). According to Wikipedia, sail components include features that define a sail's shape and function, and the foot plays a key role in shaping the sail's aerodynamic profile. On a mainsail, it is typically attached to the boom via a bolt rope or slides, though loose-footed mainsails are also common, where the sail is only fixed at the corners. On a jib, the foot is always free and tensioned through the clew. The foot length is specified in sail dimensions and measured in meters or feet; do not confuse with the imperial unit 'foot' (plural 'feet'). For a mainsail, this measurement is often denoted as 'E' in rig dimensions. The exact length is measured straight-line between the centers of the tack and clew.

Foot tension is adjusted with the outhaul, which stretches the sail along the boom. Increasing tension flattens the sail, reducing draft and power—useful in strong winds. Easing the outhaul adds depth to the profile, increasing drive in light air. For example, in fresh breeze, it's advisable to tension the foot firmly to reduce heeling and maintain control. In light wind, conversely, ease the outhaul to create a fuller shape and more power. Proper adjustment directly affects boat speed and handling. When performing maneuvers like tacking and gybing, correct foot tension helps maintain control. Working the outhaul often involves winches and blocks; the basics are covered in Yacht Rope Handling: Winches and Blocks for Beginners. For a broader look at sail trim, see the Sail Handling & Trim section.