Tack is one of the busiest words in sailing, with three distinct meanings that every sailor uses daily. 1. The tack of a sail is its lower forward corner, where the luff meets the foot; on a mainsail it sits at the gooseneck, on a headsail at the stemhead or furler drum. 2. To tack is to turn the bow through the wind so the sails fill on the other side; it is the manoeuvre that lets a boat zigzag upwind. 3. The tack a boat is on – port or starboard – describes which side the wind is coming over, and is defined by the side opposite the boom. Beginners keep the three apart by context; experienced sailors know that the first meaning shapes a sail, the second wins or loses races, and the third decides who has right of way.
Tack as the corner of a sail
The tack is the anchor point of the sail. On a mainsail it is fixed to the boom at the gooseneck by a pin or a shackle, and the cunningham or tack downhaul pulls down just above it to tension the luff. On a headsail the tack shackles to the stemhead fitting or the furler drum, and its height above the deck sets where the foot sweeps relative to the lifelines. On an asymmetric spinnaker the tack is attached to a tack line led to the bow or bowsprit, and easing that line lets the sail rotate to windward and project in front of the boat.
For the sailmaker the tack is a heavily reinforced corner with radiating patches and a stainless ring or webbing loop. The angle between luff and foot at the tack, along with the tack’s position relative to the mast and boom, determines how the sail sits when hoisted. A reefed mainsail has a new tack at the reef cringle, which must be hooked down firmly before the halyard is tensioned; a reef with a loose tack loads the sail badly and pulls the draft aft.
Tacking as a manoeuvre
To tack, the helm turns the boat toward the wind, the bow passes through the eye of the wind, and the boat settles onto the new tack with the sails filled on the other side. Because a boat cannot sail directly into the wind, tacking is how you make ground upwind, working from one close-hauled course to the other. Most keelboats tack through 80 to 90 degrees; performance boats through less, heavy cruisers through more.
- Prepare: the crew take up the lazy sheet and check the working sheet is ready to release. The helm calls “ready about”.
- Turn: “helm’s a-lee” or “lee-oh”, and the helm puts the bow into the wind smoothly, not violently, so the boat carries speed through the turn.
- Release: as the headsail backs, the working sheet is released and the new sheet taken in quickly, ideally before the sail fills and loads up.
- Settle: the helm comes off the wind a few degrees to build speed, then hardens up to the close-hauled course as the boat accelerates.
Common mistakes are turning too slowly, so the boat stalls head to wind and is in irons, or too fast, so speed is lost to rudder drag and the boat falls off far below close-hauled on the new tack. On bigger boats the gain comes from a smooth turn and an early, clean sheet release.
Tack as a designation
A boat is on starboard tack when the wind blows over her starboard side and her boom is to port, and on port tack when the wind is over her port side and the boom to starboard. The boom, not the compass course, is the test; a boat running square with the boom to port is on starboard tack even though the wind is nearly astern. Under both the Racing Rules of Sailing and the international collision regulations, a port-tack boat keeps clear of a starboard-tack boat. This makes the starboard tack the strong tack at a start, at a crossing and at a mark.
Related terms
The other corners of a sail are the head and the clew; the edges are the luff, leech and foot. Turning the stern through the wind instead of the bow is gybing or jibing. A boat that stalls head to wind during a tack is in irons or has missed stays. A tack line controls the tack of an asymmetric spinnaker.
Frequently Asked Questions about Tack
How do I know which tack I am on?
Look at the boom. If it is out to port, the wind is coming over the starboard side and you are on starboard tack. Boom to starboard means port tack.
Why does the boat stop when I tack?
Either the turn is too slow, so the boat loses way head to wind, or the headsail is released too early and the boat has nothing to pull the bow through. Carry speed into the tack, turn steadily and hold the jib until it starts to back.
Three meanings, one word, and you will use all of them on any sail. Know where the tack of every sail is and that it is properly secured, tack the boat smoothly with the sheets ready, and always know which tack you are on before another boat is close enough to ask.