Sailing know-how / How sailing works / Sail trim
Sail trim
Well-trimmed sails make the boat faster, more upright and easier to steer. All it takes is a few controls and a look at the telltales.
The basic rule
When in doubt, let it out. Ease the sheet until the luff just starts to flutter, then pull it back in a little. The sail is then at its best angle to the wind.
The headsail
- Sheet: sets the angle of attack. The telltales on both sides should stream horizontally.
- Sheet lead (car): controls tension on leech and foot. If the sail lifts at the top first, move the car forward; if at the bottom first, move it aft.
- Furling: in more wind roll away some genoa and move the car forward.
The mainsail
- Mainsheet
- Pulls the boom down and towards the centre. Tight upwind, well eased on a reach.
- Traveller
- Moves the boom sideways without twisting the sail. Drop it to leeward in gusts to spill pressure.
- Kicker (vang)
- Holds the boom down off the wind so the sail does not twist too much.
- Cunningham / outhaul
- More tension flattens the sail, which is good in strong wind.
Heeling too much?
If the boat heels too far and becomes weather-helmed (turns into the wind by itself), you have too much sail up. First drop the traveller, then flatten the sails, and if that is not enough: reef. A boat heeling 15 to 20 degrees is usually faster than one at 30.
From my own experience
Trimming is like tuning an instrument for me. When all the telltales stream cleanly aft and the boat quietly accelerates, it is a great feeling. I like to let everyone in the crew play with the sheet.