Downhaul

A line or tackle used to pull a sail, spar or fitting downwards or towards a lower control point.

Its function depends on the rig. A mainsail downhaul can tension the luff or pull a sliding gooseneck down; a jib downhaul can help lower the sail; and other downhauls control poles, tack lines or retrieval systems.

A Cunningham is a specialised sail-shape control acting through a cringle above the tack and is related to, but not always interchangeable with, a tack downhaul. More tension does not universally flatten every sail safely, so the line, attachment and manufacturer or sailmaker limits must be understood.