The short version
- What a tack costs
- Measured on Sail Tactician's own race recordings, a typical tack loses about 45% of boat speed at its slowest point, measured from the moment the bow crosses head to wind. Most of that is rebuilding speed afterwards, not the turn itself.
- Do it well
- Enter at full speed, turn smoothly, come out on your close-hauled angle, no wider, and let the boat accelerate before you sheet in hard and point.
- The common faults
- Turning too fast or too slowly, overturning onto a reach, and sheeting in too early so the boat can't build speed.
- Tack less, too
- Every tack has to earn its cost. Sail Tactician's coach allows two tacks plus one per 300 m (1,000 ft) of beat before it calls it over-tacking.
What a tack really costs
Most sailors think of a tack as a few seconds of turning. The speed trace tells a different story. When Sail Tactician measured tacks on its own race recordings — a small sample — a typical tack lost about 45% of boat speed at its slowest point, measured from the moment the bow crossed head to wind.
Where you measure from matters a lot. The boat is slowest right around that crossing. A method that starts measuring a few seconds later, after the tack has been spotted, has already missed the dip: one such method read the same tacks as losing about 6%. So if an app or instrument tells you your tacks are almost free, be suspicious of when it starts the clock.
That shape has a practical lesson. The turn takes a few seconds; the recovery takes much longer. A tack that loses a little less speed but gets back to pace twice as fast is the better tack, which is why good sailors talk about the exit more than the turn.
How to tack, step by step
- Build full speed first. A slow entry has nothing to carry you through the turn. If you've just been slowed by a wave or another boat's wind, wait a few seconds.
- Look and call. Check the water you're about to tack into for boats and waves, then call "tacking" so the crew is ready.
- Turn smoothly. A steady, progressive helm — not a snap, and not a slow drift into the wind. Too much rudder acts as a brake.
- Cross the boat as the bow passes head to wind, weight low and centered, facing forward.
- Release and trim the jib in time with the turn. Let the old sheet go as the jib backs, and pull the new one in quickly — but not to the mark yet.
- Exit on your close-hauled angle, no wider. See the next section.
- Accelerate, then point. Sail a few degrees low with the sails a touch eased until speed builds, then sheet to your marks and come up to the groove. See finding the groove.
- Get the weight and trim set immediately. Don't let the boat wallow while everyone catches their breath.
Where to come out
Your boat can't sail closer to the wind than its close-hauled angle on either side. The space between those two angles is the no-sail zone, and a tack is a turn across it. The perfect tack comes out right on the far edge.
- Overturning — bearing away past your close-hauled angle on the new tack — feels good because the boat accelerates quickly. But you've sailed off course, and you have to sail the extra distance back. A small, deliberate dip below your angle to build speed is fine; a reach isn't.
- Pinching out of the tack — coming up to your best angle, or above it, before the boat has speed — leaves the sails stalled and the boat slipping sideways. It's the most common reason a tack's recovery drags on.
Common faults
| Fault | What you see | Fix |
|---|---|---|
| Turning too fast | Big rudder angle, boat stops dead | A smoother, steadier helm through head to wind |
| Turning too slowly | Stalls head to wind, sails flapping | Commit: keep the turn going at a steady rate |
| Slow entry | Tacking just after a wave or in a lull | Wait for speed, flat water or a puff |
| Overturning | Fast exit on a reach | Watch the compass or a landmark for the new heading |
| Sheeting in too early | Points high, slow to accelerate | Ease a touch, build speed, then trim |
| Late crew movement | Boat heels hard on the new tack | Cross as the bow passes head to wind and hike at once |
Roll tacks
In dinghies, a roll tack uses crew weight to help the boat turn and keep the sails driving. It follows exactly the same course as a plain tack — the difference is all in what your body does:
- Let the boat heel a little to leeward just before you start the turn.
- Start turning and, as the bow nears head to wind, hike or lean hard on the old windward side so the boat rolls toward you.
- Stay on the old side through head to wind, then cross late, once the boom has come across the centerline, easing the mainsheet a little as you go.
- Flatten the boat on the new side with a firm hike, then trim the main back in as speed builds.
That's the one timing difference from a plain tack. In a plain tack you cross as the bow passes head to wind; in a roll tack, your weight staying on the old side through head to wind is what rolls the boat, so you cross a moment later. The common fault is starting the roll too late, after the bow has already passed head to wind, which just adds heel with nothing to show for it.
The roll fans the sails through the wind and can bring the boat out of the tack close to full speed, especially in light air. In a breeze, the roll gets smaller and the plain technique takes over.
The rules in a tack. From the moment your bow passes head to wind until you're on a close-hauled course, you must keep clear of other boats (rule 13, While Tacking). Tack where nobody has to change course to avoid you. Rolling is allowed only to help the boat turn: if the boat comes out of the tack faster than it would have without the tack, that's a breach of rule 42 (rule 42.3(b)). Class rules can change what's allowed, and at events using Appendix P, judges on the water can penalize a breach on the spot. This is a plain-English summary of the Racing Rules of Sailing 2025–2028, not a substitute for the rulebook.
Fewer, better tacks
A typical tack costs you seconds, so every tack has to earn it: a wind shift, clear air, a layline, or a boat you need to stay with. Sail Tactician's coach uses an allowance of two tacks plus one for every 300 m (1,000 ft) of beat; past that, it calls a beat over-tacked. That's a rough guide, not a measured result or a rule: a very shifty lake can reward far more tacks, and a steady sea breeze far fewer. See playing the shifts for which tacks pay.
And pick your moment. Tack in flatter water, in a puff rather than a lull, and not straight into another boat's wind.
Doing it with Sail Tactician
Every tack you sail is measured from the moment the bow crosses the wind, for the reason shown above, so the race, the debrief and the drill all use the same yardstick.
Questions
How much speed do you lose in a tack?
On Sail Tactician's own race recordings, a typical tack lost about 45% of boat speed at its slowest point, measured from when the bow crossed head to wind. The sample is small, and the figure varies a lot with boat and conditions.
How do I tack a sailboat without losing speed?
You can't avoid losing some. Enter at full speed, turn smoothly, come out on your close-hauled angle rather than past it, and let the boat accelerate a few degrees low before sheeting in and pointing.
What is a roll tack?
A dinghy tack where the crew heel the boat to leeward on entry and then roll it hard to windward through head to wind, so the sails keep driving and the boat loses less speed. The course sailed is the same as a plain tack. Coming out faster than you'd have been without the tack breaks rule 42.
How many times should I tack on a beat?
Only when a tack pays — for a shift, clear air, a layline or another boat. As a rough guide, Sail Tactician's coach allows two tacks plus one per 300 m (1,000 ft) of beat before calling it over-tacking.
Sources
Speed-loss figures measured on Sail Tactician's own race recordings, a small sample. The over-tacking allowance is the one Sail Tactician's coach uses. Racing Rules of Sailing 2025–2028, rules 13 and 42.3(b) and Appendix P, summarized in our own words. Tack and roll-tack technique adapted from Sail Tactician's in-app training guide and standard club-racing practice. Sail Tactician behavior from the in-app User Guide, version 3.2.
What changed
- First published.
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