Tacking vs jibing: which end crosses the wind, and why the boom cares

A sailboat cannot sail straight into the wind, so to get anywhere upwind it zigzags, and every corner of the zigzag is a tack. Going downwind, the corners are jibes. The two turns look similar from the shore — the sails swap sides — but they are different in one way that matters for your head: in a tack the sails go slack halfway through, and in a jibe they never do. This guide shows both turns, gives the commands you will hear in US and UK schools, and explains how to make a jibe as calm as a tack.

Which end crosses the wind

Picture the wind coming from the top of the page. If your course change makes the bow pass through the wind, it is a tack. If it makes the stern pass through the wind, it is a jibe. That is the whole definition — the size of the turn and the point of sail you start from follow from it. A tack usually takes you from close-hauled on one tack to close-hauled on the other, a turn of roughly 90 degrees. A jibe usually takes you from a broad reach or run on one side to the other, a much smaller turn.

What the helm says, and what the crew answer

Every school uses a three-part exchange: a warning, a reply from every crew member, and the call that means the turn is starting now. The words differ between the American Sailing and RYA schemes; the discipline is the same.

• The warning is a question. Nothing happens until everyone has answered. If one crew member says “stand by” or nothing at all, the helm holds course.
• Crew use the pause to check their sheet is ready to release, the new sheet is ready to trim, and their head is below boom height.
• The final call is the last word before the tiller moves. Do not turn while you are still saying it.
• Before any of it, the helm looks all round: the new course must be clear of boats and hazards before the warning is given.

Tacking, step by step

1. Sail close-hauled with speed on. A slow boat does not carry through the no-sail zone.
2. Look around, then “Ready to tack?” Wait for every “Ready”.
3. “Hard alee” and push the tiller firmly to leeward (the boom side). The bow heads up through the wind.
4. As the jib starts to luff, release the old jib sheet. As the bow passes through the wind and the sails fill on the new side, take up the new sheet.
5. Straighten the tiller as the sails fill; do not let the boat keep turning past close-hauled.
6. Crew move to the new windward side as the boat starts to heel the other way; trim the jib in promptly to rebuild speed.

Jibing, step by step — and why the mainsheet comes in first

On a run the mainsail is eased right out and full of wind. If you simply turn until the wind gets behind it, the sail is thrown across the boat in one movement — the boom travels an arc of well over a hundred degrees at full speed and stops at the shrouds with a crash. A controlled jibe changes one thing: the mainsheet is hauled in before the stern crosses the wind, so the boom only has to travel a short distance, and is then eased out on the new side.

1. Look around and pick the new course. “Ready to jibe?” Wait for every “Ready”.
2. Crew sheet the mainsail in, hand over hand, until the boom is near the centreline. Everyone checks their head is below boom height.
3. “Jibe ho” and bear away smoothly until the stern crosses the wind. The boom comes across — a short, controlled movement.
4. As the boom crosses, ease the mainsheet out on the new side and straighten the tiller so the boat does not round up into the wind.
5. The jib usually comes across on its own, gently, because the main blankets it; trim it on the new side.
6. Crew weight to the new windward side — the side the boom just swung away from.

The accidental jibe, and sailing by the lee

The boom is normally carried on the side away from the wind. If a boat on a run turns a little past dead downwind, or the wind shifts, the wind arrives on the same side as the boom — the boat is sailing by the lee. The wind now presses on the back of the mainsail, and the next small wobble of the tiller can throw the boom across with nobody warned. This is the most common way beginners get hit.

• Steer a little above dead downwind rather than exactly on it, so a small shift does not put you by the lee.
• Watch the jib: on a run it goes soft, then tries to blow across to the boom's side, just before an accidental jibe.
• If you are by the lee and the boom starts to lift, push the tiller towards the boom to head up and bring the wind back to the proper side.
• In stronger wind, rig a preventer — a line from the end of the boom led forward to a strong point — whenever the wind is aft of the beam.
• Crew: on a run, sit where the boom cannot reach you, and never stand in the cockpit facing aft.

Key takeaways

• Tack: bow through the wind, sails luff, boom crosses gently. Jibe: stern through the wind, sails full, boom crosses loaded.
• Warn, wait for every “Ready”, then turn. ASA: “Hard alee” / “Jibe ho”. RYA: “Lee-oh” / “Gybe-oh”.
• Sheet the main in before a jibe so the boom travels a short distance, then ease it out on the new side.
• By the lee — wind on the boom's side — means an accidental jibe is close. Head up towards the boom to fix it.
• In strong wind, tack around instead of jibing. Head below the boom for both turns.