Windsurf Sail Trim: 3 Rigging Mistakes Almost Everyone Makes

Windsurfing is simple and beautiful, but the equipment and the technique can get complex. With so many factors combined, the possible mistakes are practically endless.

Still, there are a few mistakes I see all the time. They show up at every skill level, and they seriously cost you fun and performance on the water. Here are the three most common windsurf sail trim and rigging mistakes, how to recognise them on the water and how to fix them. Prefer to watch? The full video is at the end of this guide.

Mistake 1: Too little downhaul

This is the one I see most. It often comes together with too much outhaul. That combination is actually a trick I recommend for sailing a fin sail on a foil (see my wind foil trim guide), but on a fin it makes things very difficult.

What downhaul does to the loose leech

Downhaul is one of the factors that decide how much your mast bends and how much the top of the sail comes loose. That decides how much the sail twists, and the twist is what lets the sail open when the wind hits it.

Why it matters at speed

When you start planing, the apparent wind doesn't play a big role yet. But your own speed adds a headwind, so the faster you go, the stronger the apparent wind gets and the further forward it comes from. At cruising speed it comes at you from about 45 degrees. If the upper leech doesn't open now, the sail doesn't twist and you run into resistance very soon. At a certain point you don't go any faster: the pressure in the sail just keeps increasing and can't be turned into speed. That pressure also pushes the nose of the board down onto the water.

That's why the right downhaul tension, and the right amount of loose leech, is crucial for easy sailing and maximum performance.

How too little downhaul feels

• The nose of the board doesn't come free.
• You feel a lot of resistance and stop accelerating at a certain speed.
• The pressure in the sail increases disproportionately in gusts.

The fix: how much downhaul

The easiest way to find the right downhaul is when your sail maker gives you indicator points on the sail. If your sail has them, bring the loose leech to somewhere between those two points and trust your sail maker. Every brand has a different design philosophy, so the perfect downhaul differs from brand to brand, and even from model to model.

If you still feel the symptoms above, increase the downhaul in 0.5 to 1 cm steps until it feels right.

Gone too far? Signs of too much downhaul

Over-downhaul the sail and you get the opposite problems:

• The top of the sail opens too much and starts to flap.
• The pressure point becomes very undefined. You keep moving the sail back and forth and struggle to find the right position.
• The loose leech opens so much that it gets very difficult to turn back-hand pressure into pressure on the fin.
• The difference in pressure between a lull and a gust feels bigger, the more you over-downhaul.
• When you hit a gust, the board wants to climb and the nose wants to rise.

If that's you, decrease the downhaul by 0.5 to 1 cm at a time until everything feels right and the problems are gone.

Careful: too little back-hand pressure can also come from harness lines that sit too far back. It's not always the downhaul.

Mistake 2: Too much outhaul

Another frequent misconception is putting way too much tension on the rope between the clew and the end of the boom. I've even seen people use their feet to pull it. Do that and you completely lose the shape of the sail.

Why shape matters

A deep profile, like in a slalom race sail or a foil sail, gives you a more stable feel. When you hit a gust you won't feel as out of control. A sail with less shape is more nervous. That's why even manoeuvre sails are meant to have a slight profile instead of being completely flat.

In sails without cambers, the profile only forms once the wind hits the sail. With too much outhaul the sail simply can't build up a profile. So don't kill your sail with the outhaul.

How too much outhaul feels

• The sail stays completely flat, even with pressure in it.
• The pressure difference between lulls and gusts is big.
• You get too little back-hand pressure.
• It's hard to get planing.

Too little is no good either

Too little outhaul creates an inefficient profile. The sail blows up and doesn't really release the pressure anymore. You feel a resistance at a certain speed, and the sail powers up but you don't accelerate.

There is one exception: when the wind is light and you should really be on a bigger sail, a bit less outhaul creates more pressure in the sail and helps you get planing.

The fix: how tight the outhaul should be

A good rule of thumb for the right outhaul: when you sheet in, the sail should just touch the boom.

Mistake 3: The wrong mast (bend curve)

It's widely underestimated how much of an impact the right or wrong mast has. And not only on performance: the wrong mast can cause exactly the same problems as too much or too little downhaul or outhaul.

Different brands have different design philosophies. Some believe a mast should flex more towards the top, others believe it should bend constantly. It's a complex topic, and Unifiber explained it really well in their blog post on windsurf masts. Here's the simple version of what you need to know:

• Use a mast that was designed for your sail. The safest option is a mast from the same brand as your sail.
• The bend curve beats the carbon. You're better off with a perfectly matching 65% carbon mast than with a 100% carbon mast with the wrong bend curve.

Get these three right and you've avoided the most common rigging and trimming mistakes. Below is the whole routine in four steps, plus a checklist to save on your phone for the beach.