Reefs: How Many and Where

Whether you’re heading out for a day sail or even an offshore passage, it’s important to be prepared for all conditions. Reefing your sails is an excellent way to enjoy big breeze, while still keeping safe and comfortable. Whether you have a traditional rig or furling mainsail, it’s always good to practice reefing technique.

Before heading out for the day, be sure to check conditions, and don’t wait for things to get too rough. It’s easier to shake out an unnecessary reef than it is to put it in while underway in breezy conditions.

Reefing can protect your boat from damage and make the sail more comfortable, but if it isn’t done properly, it can add extra wear and tear to your sails. Make sure to protect the luff of your sail by putting the luff tension on first whether you have a boltrope main or a slide main. Release the outhaul and vang before dropping the mainsail down to the desired reef position. Keep the sail pulled forward by securing the tack of the reefed main and take-up on the halyard to ensure there is good tension on the luff. After the luff is secure and tight, take up the slack on the reef line on the clew and make sure there is good tension on the foot of the sail.


Give the number and location of reefs in the mainsail some thought. The typical cruising mainsail configuration uses two reefs normally placed at intervals of approximately 12 percent of the luff length. They do not reduce area as a standard percentage. In fact, a first reef will reduce more area because the sail is wider at the bottom.

A third reef is sometimes added for offshore work, again at another 12 percent of luff length (36 percent). But few boats are set up with reef hardware for three reefs. The third reef will slightly decrease the overall durability of the sail by adding weight to the leech and necessitate hardware changes to the boom to allow for a third reef line.

If you don’t plan to sail offshore, two reefs will be plenty. In fact, most sailors who limit their sailing to local trips don’t sail for extended periods in high winds. The only high wind they will see will be in localized squalls. In this case, they’ll probably take the mainsail down completely.

Another approach to reefing for offshore sailing is to space two reefs at slightly deeper locations than normal, approximately 15 percent and 32 percent of the luff length. With offshore sailing in mind, deeper reefs make sense, but this also depends on your boat. Certain boats may need more mainsail or balance particularly well with a 12-percent reef. The struggle involved with moving from a second to third reef is an indication that being more conservative and taking away more area with each reef is simpler and generally makes the most sense.

Sailmaker Tip: Serious offshore sailors often opt for a storm trysail and eliminate the third reef. However, you’ll want to make sure you have a secondary track for the trysail. Without a secondary track, using a trysail is generally not practical.


Using a single line to control both the reef tack and clew has become popular, but recognize that single line systems introduce a great deal of friction, particularly when they are led back to the cockpit, which can make it hard to reef.

Single-line systems work better with blocks in the reef tack and reef clew instead of standard grommets. Care must be taken to address the angle of the tack reef line, position of the tack grommet, and hardware spacing relative to the reefed tack. You want the reef grommet at the tack to pull the sail forward to prevent excessive loading on the slides. Be sure to discuss this with your sail consultant prior to design of the sails.


One of the greatest added benefits to in-mast or in-boom furling is that you may have conceivably infinite reefing points. Since there is no modification required to the sail, you can select the desired sail area to suit the exact conditions.

Here are some tips to execute your reef successfully and to prevent additional strain on you, your sails, and equipment. Alignment and tensions are critical.

In-mast furling requires a fair lead through the slot in the mast to achieve the best and easiest furl. Once you’ve decided to depower, prepare your furling line with a few wraps on the winch. Head up into the wind, apply tension to the outhaul on your winch, and then release the outhaul clutch. Easing the outhaul in concert with taking up on the furling line will reduce flogging and create a well-furled sail. Close the clutch on your furling line and snug the outhaul to achieve the desired draft in your mainsail. Make sure your boom is at no greater than a 90º angle to the mast when furling; you may have to ease the sheet a fraction to achieve this. The sail doesn't like to be pulled down when it is trying to roll forward.

In-boom furling is similar to in-mast furling, but you won’t be easing the outhaul. Instead, you will be easing the halyard as you furl. Be mindful of the tensions if you are using electric winches for in-mast or in-boom furling to prevent tears or stretch as your full-hoist marks will not be in the same locations.

It’s important to know the limits of your boat and your crew and to be prepared for breezy conditions. By using reefs, you can increase the number of enjoyable days spent on the water. Contact your sailmaker with more questions about reefs and how to use them.

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