At a special NorthU Sail Trim class in Phoenix, expert sailor Andrew Kerr taught us how to get the most out of our sails. We also asked him to answer some questions for Compass Points magazine on how to deal with our typical light-air sailing. Here's what he said:

A PDF of the Compass Points story available here.

Q: Sailing on a beam reach in very light air, my competitors seem to move faster when trimmed for a close reach. Can you explain why this might be true (or not true)?

A: The key element on a beam reach in light air is not to over-trim and stall the sails, but to keep the boat moving fast in the lulls by generating apparent wind on the sails. This is best accomplished by heading up in the lulls and then bearing off in the puffs toward the mark. 

Another key element is not to let the boat sail too low in the lulls since the boat will take a lot of time to regain momentum.
Have a crew member talking about the lulls and puffs and keep an open mind with trim—try to remember that a stalled sail (trimmed too tight) takes twice as long to reattach airflow as a sail on the verge of luffing.

Test the trim, particularly by easing the genoa, which will enable the mainsail to be eased too as a result of opening the slot. Make sure that the vang is not too tight. In light air have the top baton on the mainsail five degrees to leeward of parallel to provide a more open shape that will promote flow on the sail. So much of light air reaching is about staying in the velocity. Have a crew member talking about where the best puffs are and whether it’s worth sailing high or low to stay in them.

Q: What’s the best mainsail trim for downwind running in light air?

A: Good mainsail trim downwind in light air is accomplished with medium outhaul tension, no Cunningham, no backstay, and the vang set so the top baton on the mainsail is a little more open than usual—five degrees from parallel to the boom.

We play the vang downwind. In puffs we will squeeze it on to keep the top baton parallel to the boom and in lulls we will ease it off so it is not too tight. This is a boat-speed element that’s generally overlooked. Be sure to keep easing the main sail until it’s on the verge of luffing and then re-trim.

Common trim errors in light air running include: vang too tight, mainsail over-trimmed and the outhaul eased too much, which actually reduces projected area.

Q: What’s the optimum mainsail leech shape for upwind sailing in light air? (Does a “Boomkicker” or solid vang help create this shape?)

A: In light air upwind, you’re trying to keep the top baton about five degrees to leeward of the boom and keep the boom on centerline. This is mostly accomplished by having the mainsail traveler all the way up to windward, the vang very soft (have a crew member touch the vang once in a while to make sure it is not too tight) and the mainsheet eased so the top baton is open—otherwise known as creating twist.

Twist is fast in light air as a more open leech promotes a better flow on the sail. As the wind gradually builds we can apply more mainsheet tension to obtain pointing ability since the boat is moving better. Boat speed is a key element and once obtained will provide pointing ability.

In the lulls we ease the sheets—open the sails and go into more of a fast-forward mode. In the puffs we’ll trim the sheets and squeeze the leeches to obtain pointing—but only when we have boat speed. Our mantra here is to “ease and squeeze” the leeches of the sails to keep the boat moving fast in both the lulls and the puffs.

A Boomkicker or solid vang can help light air shape upwind by taking the weight off the boom and helping keep the leech open and flowing.

Q: Is my ability to point higher influenced mostly by sail trim, rig tension, mast rake, or what?

A: The ability to point high is a function of all those factors that you mention. The key element we focus on is boat speed, since that produces pointing through more lift on the foils. When you’re moving well, both the keel and rudder are more effective lifting foils.

Try not to pinch, particularly if there’s chop. Try to keep the boat rolling and then ease it up in the puff. Set rig tension for the lulls rather than the puffs, since this will give the boat more power. If the wind is, say, six-to-10 knots, we’ll look at the tuning guide and set the boat up for the six knots, knowing that we need the power in the lulls. This is true across the spectrum of conditions unless the boat is consistently very overpowered.

Another critical element is to try to sail the boat a little more level than your competition. Granted you want heel in light air, but I find as a coach that a lot of teams heel too much in all conditions. Try sailing the boat five degrees flatter than you are now in all conditions. It’ll take some getting used too as the helm will be lighter, but the benefits will be seen in more effective foils and less leeway and consequently higher pointing.

One of the common traits of the top boats in fleets all over the country is that they sail the boat a little flatter. As a team, strive for this. Very often it boils down to hiking harder than the other teams!