To reef is to reduce the area of a sail so the boat stays upright, balanced and under control as the wind builds. As a noun, a reef is one step of that reduction – the first reef, the second reef – marked by a reinforced cringle at luff and leech and a row of reef points across the sail. Beginners learn that reefing keeps the boat safer; experienced sailors know it also makes the boat faster, because a reefed, properly flattened sail drives a boat that is on her feet far better than a full sail dragging the rail through the water. In navigation the word also means a ridge of rock or coral near the surface, which is an entirely separate hazard and not the subject here.
How Reefing Works
Every reef system does the same three things: it lowers the head of the sail, secures a new tack, and secures a new clew, so that a smaller, flatter triangle of cloth is set on the same spars. On a mainsail with slab reefing (also called jiffy reefing) the halyard is eased, a reef cringle on the luff is hooked or pulled down to the gooseneck, the halyard is re-tensioned, and a reefing line hauls the leech cringle down to the boom and aft to tension the new foot. Reef points then gather the loose bunt of cloth along the boom.
Why Reefing Matters for Shape and Speed
A boat sails fastest and points highest at a modest heel angle. Past about 20 to 25 degrees the keel and rudder lose efficiency, weather helm climbs, and the boat starts rounding up in gusts. Reducing area lowers the heeling force and moves the centre of effort down and forward, easing the helm. Just as important, a reefed sail should be flatter than the full sail: the reef clew cringle is cut so the new foot pulls tight along the boom, and a good sailmaker draws the reef positions so the reefed sail has its own fair shape rather than being a random slice of the full one. Reef points are only there to tidy the bunt; they must never carry load.
When to Reef
The old rule is the right one: the time to reef is when you first think about it. Concrete signs are sustained heel beyond about 20 degrees, a helm that needs more than a few degrees of correction, the boat rounding up in puffs, or a forecast for more wind before nightfall. Reef before dark and before the sea builds. Shaking out a reef in daylight when the breeze fades is a pleasure; putting one in on a pitching foredeck at 0300 is not.
Technique and Common Mistakes
- Prepare: ease the vang, take up the topping lift or lock the rigid vang, and bear away slightly or luff so the main is depowered but not flogging.
- Lower: ease the halyard to a pre-marked position so the luff cringle reaches the hook or the reef tack line.
- Secure the tack: hook the cringle or tension the tack line, then re-tension the halyard hard.
- Secure the clew: grind the reefing line until the new foot is tight along the boom.
- Tidy: tie the reef points loosely around the bunt only – around the sail, not around the boom on a loose-footed main.
The most common mistakes are leaving the reefing line slack so the reefed foot sags into a deep, powerful bag, forgetting to re-tension the halyard so the luff scallops, and tying reef points tight enough that they tear the sail when the clew line is later eased. Mark halyards and reefing lines so the job can be done by feel at night.
Cruising Versus Racing
Cruisers reef early and deep, often carrying three reefs in the main and specifying a deep third reef as a storm-sail substitute. Single-line reefing systems trade friction for the convenience of doing everything from the cockpit. Racers reef the main last: they change to a smaller headsail first, pull on backstay and outhaul to flatten the sail, and use a flattening reef – a shallow cringle just above the clew – to remove the lower shelf and foot round without losing much area. Only when those tools are exhausted does the first proper reef go in.
Frequently Asked Questions about Reefing
How much area does one reef remove?
Typically 15 to 20 per cent of the mainsail per reef, with the second reef often set deeper than the first. Your sailmaker positions reefs according to the boat’s stability and how you sail.
Should the reef points carry any load?
No. The tack and clew cringles carry the load; the points simply gather the loose cloth. Tie them loosely so they cannot tear the sail if the clew line is eased.
Reefing well is one of the clearest marks of an experienced crew. Do it early, do it properly with the tack and clew tight, and the boat rewards you with a lighter helm, less heel and, more often than not, a higher average speed.