Simon ‘Stir’ Fry is a world-class trimmer with wins in a huge range of classes. He shares headsail trimming and set-up tips with Andy Rice

The challenge of headsail trimming, according to Stir Fry, is understanding at any given moment what the team is aiming to achieve. On a busy race course, those aims are ever-changing.

Whether you’re going for VMG speed in open water, footing through some bad chop or sheeting in hard to live in a thin lane, the trimmer needs to be in sync with the helmsman and the mainsheet trimmer for the ‘speed loop’ as well as knowing what the tactician and strategist are thinking.

One of the big differences, Fry believes, between a fully pro team and typical amateur race crew is the level and quality of the conversation – and headsail trimming is a key part of this communication loop.

“Let’s say you’ve just started and you’re two minutes into the race. Five boats have popped out while three boats tacked onto port, but it looks like we need to sail on for another two minutes to open up a lane in the middle of the course,” Fry explains.

“The tactician will say: ‘I need to live in this lane for another 45 seconds.’ Then the driver will say: ‘Okay, trimmers, just give me a little bit more sheet tension, and I’ll be happy to sail 1/10th under target speed.’ So it will be then a very, very small change in mainsheet trim and jib trim. The trimmers then respond by sheeting in and asking if that feels okay to the helmsman, and so on. It’s a constant conversation.”

Even if it’s a very specialised role with a lot of the time looking up at the telltales, the best trimmers have a global understanding of the race course at any given moment.

“A beautiful looking jib is not necessarily what you’re looking for at all times,” Fry points out. To understand why, read his five best tips on headsail trimming.

Create a comms loop

A strong team has a strong comms loop and the trimmer plays an important role in listening and also communicating what’s needed at any given moment on the race course. There’s always an element of compromise to what the boat needs, what the mainsheet trim is doing and how the boat is being steered.

A perfect-looking jib is not necessarily what you’re looking for, other than when you’re in perfect conditions. You’ve nearly always got other boats to think about, where tactical situations might dictate a different setup in the sails and how the helmsman is steering. This is why the comms loop is critical.

Balance over beauty

The most important speed goal is for the helmsman to have a balanced rudder. Sometimes you have to contort the sail to give the boat what it needs. In very light airs sometimes you’ve got to go to extremes to make the boat go well. That might be inducing massive headstay sag and making the leech very round in the back. Then in very strong conditions it’s all about the boat being balanced and wanting to go in a straight line with minimal helm movements.

As [multiple world champion] Vince Brun taught us when we were kids: if a gust hits and the boat doesn’t go faster, your trim is not correct. Something needs to change to make the boat want to accelerate without the helmsman needing to do much.


Transverse genoa track gives full control of jib leech tension for both inboard and outboard leads without the need to change sheets

Know your modes

Good calibration will help you get into the right mode for the right situation. It’s about knowing how to change gears quickly and doing it in sync with the rest of the team.

Say you want to go to a fast-forward mode, you’ll probably move the jib car outboard slightly. You might make the entry slightly blunter. On a TP52 that might mean easing the sheet 10mm – which doesn’t sound very much, but when you’re dealing with high aspect, very flat-backed jibs, it’s enough to have the boatspeed pop from 9.2 to 9.6. That’s a dramatic change.

Although you won’t see such a big jump in lower performance boats, the same principles still apply.

If in doubt, go large

Good headsail trimming comes from a sailor who knows what headsails they have on board and knows what the crossovers are between those sails.

Tactical considerations come into play when deciding what size of sail to use in crossover conditions. If you’re going to sail in slop, or big waves, you might need to generate a little more power through the waves, so sail with more twist and more depth. But a general rule of thumb is to set up for the lulls.

For example, racing on a typical day in Palma, it’s nearly always lighter at the bottom of the course than at the windward mark. So when we’re going downwind we have a discussion about what jib to choose for the next beat and, more often than not, we’ll choose the bigger option to help us get through the lulls as we come out of the leeward mark. It’s easier to depower a big sail than make a small sail bigger. So if in doubt, go large.


Make sure you have a row of telltales near the luff to give you a clear signal about the trim of the headsail. The placement of these telltales can vary depending on the kind of the boat you’re sailing.

Some boats you sail soft on the luff, and by using a lot of runner you can make the entry a lot finer, so the helmsman sails with the luff of the headsail lifting slightly most of the time. In this case you should have a row of telltales around 300-400mm back from the luff.

On most boats, your normal upwind trim will be to have the leeward telltale streaming aft, with the windward telltale lifting to somewhere between 30-45° above horizontal. If you’re going for speed and footing slightly, then telltales on both sides of the jib will be streaming aft.

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