A sleeve, in sail terms, is a tube of cloth sewn along the luff of a sail that slides down over the mast, so the sail is attached by wrapping the spar rather than by a bolt rope, slides or hanks. A sleeved luff (also called a luff sleeve, mast sleeve or sock luff) is the attachment method on the ILCA/Laser, Sunfish, many windsurfers, most beach and racing catamaran mainsails and some small cruising boats’ sails. Beginners meet it as the way a Laser rig goes together: slide the sail onto the mast, step the mast, sail. The experienced sailor knows why it is done: the sleeve fairs the mast into the leading edge of the sail and removes the gap that a conventional luff leaves, which is an aerodynamic gain on a small rig. The same word also names a swaged wire fitting, a Talurit or Nicopress sleeve, which is a different thing entirely.
How a Sleeved Luff Works
The sleeve is a strip of cloth folded over and stitched to the luff of the sail to make a pocket wide enough for the mast plus some clearance. The sail is fed onto the mast from the top before the mast is stepped, or the mast is fed into the sleeve from below on an unstayed rig. Because the sail wraps the spar, there is no halyard; the sail is held at the top by the closed end of the sleeve or a head cap, and luff tension comes from the downhaul or cunningham pulling the tack down. The sail is free to rotate around the mast as the wind changes side, so the mast always sits at the very front of the aerofoil.
A sleeve almost always goes with an unstayed or minimally stayed mast, since a sleeve cannot pass shrouds or a forestay attached above deck. That is why you find it on dinghies, boards and cats and hardly ever on a stayed cruising rig.
Why Sailmakers Like It, and What It Costs
On a conventional luff the mast sits ahead of the sail with a gap or a groove between them; air separates off the back of the round mast and reattaches somewhere down the sail, and the first part of the aerofoil is lost. A sleeve wraps the mast in cloth so the leading edge is one continuous curved surface. On a small rig where the mast is a large fraction of the chord, that is a measurable improvement in drive and pointing.
The costs are practical. A sleeved sail cannot be reefed or dropped while the mast is standing, which rules it out for most cruising boats. The sleeve cloth takes the full brunt of ultraviolet and mast chafe, so it is built from heavier cloth than the body of the sail, and it will still wear through before anything else. Cutting a sleeve is exacting work: it must match the mast diameter and taper closely, and its round must match the mast bend, otherwise the sail sets with a fold along the luff or binds when you try to rotate it.
Sleeve, Bolt Rope, Slides and Hanks
- Sleeve: cloth tube over the mast. Best aerodynamics on small rigs, no halyard, cannot be reefed or lowered with the mast up.
- Bolt rope: a rope sewn into the luff that feeds into a groove in the mast. Clean leading edge, common on racing dinghies and many keelboats, can be lowered but may jam when reefing.
- Slides or slugs: fittings sewn to the luff that run in a track. Easiest to reef and drop, small aerodynamic penalty.
- Hanks: spring clips on a headsail luff that snap onto a wire forestay. Robust and simple, common on cruising headsails without furlers.
Care is simple: rinse the salt out of the sleeve, wax the mast so the sail rotates freely, patch the head of the sleeve before it chafes through, and store the sail rolled rather than folded across the sleeve.
Frequently Asked Questions about Sleeves
Why does a Laser sail have a sleeve instead of a halyard?
The sleeve makes the rig simple, light and aerodynamically clean. The unstayed mast is fed into the sleeve, stepped, and the downhaul provides all the luff tension needed; there is nothing to hoist.
Can a sleeved sail be reefed?
Not in the usual way. Some cruising sleeved sails have a zip or a lacing that lets the sleeve be opened, but generally the answer is to change down to a smaller sail or a shorter mast section.
Is a sleeve faster than a bolt rope?
On a small rig where the mast is a significant part of the chord, yes, because it removes the separated flow behind a bare mast. On a larger stayed rig the difference is small and the practical drawbacks outweigh it.
The sleeve is the simplest way to put a sail on a mast and, on the right rig, one of the most efficient. It trades reefing and convenience for a clean leading edge, and any dinghy or board sailor who has felt a sleeved rig come alive in a puff knows why that trade is worth making. See also luff, bolt rope, cunningham and unstayed mast.