Most sailboats can sail at about 45 to 50 degrees off the wind. For example, if the wind is coming from the north, you can sail northeast or northwest. Tacking, or coming about, is turning from one side of the wind to the other by turning through the eye of the wind—the direction the wind is coming from.
Tacking a Small Boat with Only a Mainsail
Prepare to tack by sheeting the mainsail in tight and sailing as close to the wind (close hauled) as possible without losing boat speed.
Alert other crew that you plan to tack. The traditional command is “Ready about!”
In a small boat with little or no ballast, you will have to move to the other side of the boat during the tack, ducking under the mast (as shown in the photo). Be sure you are free of lines and equipment and can move fast—otherwise the boat may be blown over and capsize.
When ready, alert other crew with the signal “Hard alee!” (meaning you’re pushing the tiller hard to the lee side, causing the boat to turn up and tack). Be sure to stay out of the way of the boom and move your weight to the other side as the boat comes up into the wind and is momentarily flat on the water.
As the turn continues, the boom and mainsail cross the centerline and the sail fills on the other side. Now you can steer to stay on a new heading close hauled on the other tack. Be sure not to over-steer too far on the other side of the wind, as a small boat with the mainsail trimmed in tight can be blown over and capsize. Trim the mainsail if you will not be staying on a close hauled course.
Note: in a boat with a mainsail traveler, it’s generally a good idea to center the traveler before the tack and readjust it when stable on course afterwards.
Tacking a Sailboat with a Jib
Tacking a sailboat with a jib is similar to the steps described above, with these added:
Just before starting the turn, prepare the jibsheets. The one in use must be released during the tack, and the other quickly brought in as the jib crosses over to the other side. Be sure crew are ready to follow your commands.
As you make the tack, the jib will back (be blown backward). At this moment release the jibsheet, letting it out quickly but avoiding snagging the line on anything in the cockpit. At the same time (ideally with a second crew), quickly pull in the jibsheet on the other side so that the jib is not blown flapping far out to the side. On a larger boat, get the jibsheet on a winch as soon as it is hard to pull in, and start cranking the winch fast to trim the sail to the new heading.
Possible Problems When Tacking
Tacking is usually not difficult with two or three crew when everyone’s actions are coordinated. But the following problems may occur:
Caught in irons. If you turn the boat too slowly, or try to tack without having enough boat speed, the boat may stall and stop when it faces the wind, called being in irons. In this case you usually have to wait until the wind finally blows the bow to one side. If the wind blows you backwards, turn the rudder to make the boat turn the right way. You may have to regain speed and try the tack again. Too prevent stalling, be going as fast as you can and as close to the wind as possible before tacking, and then turn quickly with the helm hard over.
Over-steering. It’s easy to accidentally turn the boat too far after a tack. If you are working your way upwind, you ideally want to go smoothly from close hauled on one tack to sailing close hauled on the other tack. If you over-steer, you have to trim the sails out to pick up speed and then gradually head up again and re-trim to a close hauled point of sail.
Snagged sheets. The jib often moves fast from one side to the other in a tack but flogs and flails about as it crosses the boat. The jibsheets may hang up or wrap on some fixture on the foredeck, occasionally making someone go forward to clear it. A large knot in the sheet at the sail’s clew may hang up on a shroud, although this will usually clear if the tension is released momentarily on the line. Prevention is the best solution. Keep some tension on both jibsheets before and during the tack. Close foredeck hatches and remove other items that may snag the sheets.
In races, the speed and efficiency with which crew coordinate their tacking actions often determines the winder. Practice often! Even cruisers should pay attention to tacking to keep the sailing safe and enjoyable.
Here’s a video clip from MIT’s sailing school showing how to tack a small sailboat.