Sail Trim Tips
Sail Trim Tips

Most sailors know how to pull on or let off a sail and how to adjust the various sail controls, but understanding the finer points of sail trim and how to trim for the very best speed and VMG, can be a different story.

Learning how to adjust your sails to maximise performance is an important skills for competitive racing sailors.

We sat down with trim expert Billy Sykes from North Sails, to get his thoughts on a few trim tips that can help make a big difference to your upwind trim:

Q: What are your top tips for headsail trim?

A: So, a good thing to do whenever you go for a sail for the first time, when you pull the headsail up or the mainsail up, you should reset the leech line.

The first first thing you should do once the sail’s up and you get going is to let the leech line off. What this will do is have the effect of making sure the leech isn’t too round and it will straighten the back of the sail out more.

As you go through the wind range, when its windy, you generally pull the leech line on more to stop the leech from flapping, but when it’s lighter airs and you have your leech line set for windy airs, the sail will be really round in the back, so you ease it to create a nice smooth flowing shape from the luff to the leech.

When sailing upwind in lighter airs, you want to make sure your headsail has a full shape so the sail is more powerful, because to generate heel angle in light airs you need to have deep sails. So, you generally have a softer backstay and you have the jib car set further forward to give the jib a fuller shape and power up the boat.

When it’s windier, you generally want to start bringing your jib car back and you’re after flatter shapes. When it gets windier the sails require less depth to generate horse power because you have more wind, so you’re trying to get rid of the shape. To do this you would have would have a tighter backstay, you’d have the jib car further back, and you’d be trying to flatten out the sail’s shape to maintain a constant angle of heel.

One last tip on headsail trim is to make sure that the leech is parallel to the mast. You want to make sure the mid leech of the sail isn’t open too much and you also want to ensure that the top leech telltale on the the top batten is always flying.

Q: What are your top tips for mainsail trim?

A: So with the mainsail trim, generally if you good rule to follow is to have the boom on centre line and make sure that the top batten is parallel to the boom.

In light airs you’ll have a soft backstay and mainsail outhaul. As the wind increases, you start to pull on the backstay and the outhaul to flatten out the sail shape. Generally a good rule of thumb is to never have the boom below the yacht’s centre line because you will lose pointing ability.

One last top tip for you MySail fans, I would be recommending that when sailing upwind, you maintain a constant angle of heel. A good rule of thumb is to keep this at about 18 – 22 degrees of heel angle, depending on your hull shape and keel.

Q: Do you have any tips for trimming communications?

A: Generally, you wanna have good communication, what we call a trimming loop going between the helmsman, headsail trimmer and main trimmer, to make sure you are all working towards a common goal.

So, generally the mainsail trimmer is communicating to the helmsman to make sure he or she doesn’t have too much weather helm or if he’s got too little weather helm then you’re bringing in the headsail trimmer to make changes to the trim, depending on the wind speed.

When we’re sailing, we’re not always sailing in 12 knots of wind, so your set-up from 5 knots to 25 knots is going to be quite different and you’re going to need to adjust the settings to help the helmsman keep a constant rudder angle. A good rudder angle is generally about 4 degrees for most yachts.

For more sail trim tips and techniques from North Sails, check out the NorthU website: