The basic parts of a sail are easy to decode: a triangular sail has three named edges and three named corners. On a sloop—a boat with one mast and two sails—the mainsail sits behind the mast, while the headsail sits in front. The usual headsail is a jib; a larger jib that overlaps the mast is called a genoa.
The luff is the front edge. It runs up the mast on a mainsail and attaches to the forestay—the line supporting the mast from the front—on a headsail. The leech is the back edge, and the foot is the bottom edge.
The head is the top corner, pulled up by a halyard—the line that raises the sail. The tack is the bottom front corner. The clew is the bottom back corner.
At first, a sail can look like a plain triangle of cloth. Then someone mentions the “luff” or “clew,” and sailing can sound like a foreign language. This article is your decoder for the parts of a sail. You will learn these two words—and the rest of the basic sail terminology—through shape and position.
First, you will meet the two main sail names on a sloop, a sailboat with one mast: the mainsail behind the mast and the headsail in front. A jib is a common headsail. A genoa is a larger jib that overlaps the mast. Next come the three corners: head, tack, and clew. You will see which corner a halyard—the line that raises a sail—pulls. Then you will learn the three edges: the luff, leech, and foot, including the edge that runs up the mast on the mainsail.
The Two Sails on a Sloop
A sloop has one mast—the tall pole—and two working sails. The Bermuda sloop is the most common modern rig, so it is the kind of boat many beginners first meet.
Behind the mast is the mainsail. Its front edge attaches to the mast. Its bottom edge usually runs along the boom, the horizontal pole that extends behind the mast.
In front of the mast is the headsail. “Headsail” is a general name for a sail in this position. The most common headsail is a jib.
You may also hear the word genoa. A genoa is a larger headsail. From the side, its back edge reaches past the mast and overlaps part of the mainsail. That visible overlap is the easiest beginner clue that you are looking at a genoa rather than a traditional jib.
Once you can tell these two working sails apart, the parts of a sail you meet next—its corners and edges—are easier to place.
The Three Corners: Head, Tack, and Clew
A triangular sail has three corners. You can remember them by starting at the top, then moving along the bottom from front to back.
The head is the top corner. A halyard—the line used to raise a sail—attaches here and pulls the sail upward.
The tack is the lower forward corner. “Forward” means toward the front of the boat. This corner is usually fixed near the mast or deck. On a mainsail, it sits near the point where the mast and boom meet. On a headsail, it is commonly secured to deck hardware.
The clew is the lower aft corner. “Aft” means toward the back of the boat. This corner is adjusted to help control the sail. Sheets—the lines used to trim a sail—attach to a headsail’s clew. On a mainsail, an outhaul adjusts the clew along the boom.
One word can cause confusion: the sail corner is called the tack, but tacking is also a maneuver that turns the boat’s bow through the wind.
The Three Edges: Luff, Leech, and Foot
Each edge runs between two corners:
- Luff: the forward edge, from the head down to the tack. On the mainsail, the luff runs along and attaches to the mast. On the jib, it runs along the forestay—the wire or other rigging that supports the mast from the front.
- Leech: the back edge, from the head down to the clew. This is the edge farthest behind when you view the sail from the side.
- Foot: the bottom edge, from the tack to the clew. The mainsail’s foot usually sits along the boom, the horizontal pole behind the mast.
Attachment details vary by boat. A mainsail’s whole foot may fit into the boom, or only its tack and clew may connect to it. A jib can also attach to its forestay in different ways. The edge names stay the same: forward is the luff, back is the leech, and bottom is the foot.
You can now look at a triangular sail and find your way around it. On a sloop—a boat with one mast, a mainsail behind it, and one headsail in front—you know which sail is which. You can also trace the head, tack, and clew around its three corners, then follow the luff, leech, and foot along its three edges. That vocabulary helps everyday instructions make sense. If someone mentions the halyard, the line that raises the sail, you know it pulls at the head. If they mention a sheet, a line used to adjust a sail, you know it acts at the clew. Keep building that picture with SailStarter’s short beginner lessons.