New to windsurf foiling or trying to tune up like a pro?

Windwise coach and Severne Team Rider, Simon Bornhoft continues his ‘Hang In There’ series, looking at different windsurfing styles and disciplines. For this issue we focus on windsurfing foiling and how to get set up for maximise flying time.

Featuring: Matteo Iachino, Mateus Isaac & Balz Muller 

Photos: Windwise / Severne 

For this feature you’ll discover:

  • How Team Severne pros set their harness lines for Foiling Racing, Slalom and Freestyle.
  • How you can set your harness lines & boom height for your Foiling sessions.

Read on to answer all these questions and more….

Hang In There: Windsurf Foiling 

“Set them short!” In the early days of foil windsurfing, there was a lot of talk about super short harness lines, low booms, and adopting a very upright over-the-board stance. This was due to using particularly small rigs in lighter winds to try to “get going” early and benefit from the super efficient lift you get from a foil. Also, especially when learning, you’re not massively powered up or leaning heavily back in the harness, like ‘normal’ planing windsurfing. So low booms and short lines were initially encouraged as it was very easy to ‘over pull’ on the boom and have the line drop out when learning to foil. However, with the progress of faster foils, dedicated foil boards, harness line set ups, sailing styles, and stances have started to cross over more between fin and foil.

To help you get a better idea of what’s going on, let’s first hear from some Team Severne pro foilers and then look at some recreational set up guidance. 

Race + Slalom + Fast Foiling

When it comes to fast foil blasting, racing and slalom, who better to hear from than the flying force that is Mateus Isaac. 

Severne Rider: Mateus Isaac

Foiling Style: Race + Slalom
Foiling Kit: Severne Hydro board / HyperGlide foil race sail / IQ
Harness Line Style & Length: SV Adjustable 28-34inch 

SB: So Mateus, how do you set your harness line length for your slalom/race foiling sessions? 

“I usually use a 28-34 inch SV adjustable harness line that I can move around and adjust accordingly. For regular fin slalom I like to use shorter lines than most because my style is slightly different, I like to be closer to the rig and kind of on top of the board. But for foiling, I will use a slightly longer line compared to my fin slalom set up. And then, just like fin slalom, I’ll trim my adjustable lines – setting them even longer for stronger winds and shorten then back up again for lighter winds.” 

SB: How do you position them on the boom? Are there any on water trimming methods you use or recommend?

“For foiling I like to have slightly more pull on the back-hand than on the front-hand to really feel the drive and power. 

SB: How do you set your boom height on the Foil board, is that different from regular Slalom or Freeride set up?

“Boom height is about the same, it’s usually around chin/mouth height when standing on the board.” 

Now let’s hear from the rapid Italian and foiling maestro himself, Matteo Iachino. 

Severne Rider: Matteo Iachino 

Foiling Style: Race + Slalom
Foiling Kit: Starboard / SV HyperGlide
Harness Line Style & Length: SV Adjustable 34-44inch 

SB: What length lines do you use for Foil racing?

I usually use between 34 and 44” lines depending on the wind strength and sail size. The stronger the wind, the longer the line, in general, I use around 40” lines.

SB: To give everyone an idea of how that relates to your arm length if you put your elbow in the apex of the harness line, where would the boom come to on your hand? 

For foiling, it’s elbow to finger tips or barely touching the boom.

SB: Do you position them any differently for Fin Slalom and Foil Slalom?

The SV FoilGlide, HyperGlide, and HGO IQ foil sails have less back hand pressure compared to slalom sails, therefore compared to a regular slalom sail I’ll send them further forward. You don’t want to position the lines so far back, otherwise, you will lose balance.

SB: What about your boom height?

For foiling racing you want to sail with the boom really high, with the harness lines long and forward on the boom and you really sit down on them and control the drive of the sail more with the back-hand.

Slalom Race Summary

Okay, so for the racers, it would appear they are going for longer lines, with Matteo Lachino using extremely long lines, even longer than standard fin set up. This is due to the fact that they are now racing so much more powered up and often heeling the whole board and foil massively over to windward to gain control on the sinew sapping upwind and acute mega downwind sailing angles. In race, slalom, and IQ events, the longer lines are encouraging a more hunched, flexed body positions to help hold the rail steady in full flight. This is the opposite of a more upright stance when recreational foiling on smaller sails and larger foil set ups.

As for positioning, due to the sensitivity of the foil trim and constant rig trimming, racers use a more sensitive harness line set up (slightly further forward) to help notice small twitches in rig position and wind changes. Whereas in fully powered regular fin slalom (and freeride sailing) the boards are more stable at high speeds, so the ethos has always been to massively load up, lock down and set the lines to do all the holding on, with proportionally less pull on the rear arm.

Freestyle Foiling

Now let’s venture into the more playful dimension of Freestyle foiling. So whether you’re experimenting with chucking in some duck gybes, playing with some feasible 360’s or freeing the foil from the water, there’s nobody better than the foil freekster himself, Balz Muller. Yes, this is a man who lives a gyrating ankle defying Top Gun turning existence every time he takes to the water. Let’s see what he has to say about his foiling kit set up.

Severne Rider: Balz Muller
Foiling Style: Freestyle
Kit: Freestyle Foil Board & SV Foil Freeks
Harness Lines Length & Style: 30-32cm lines.

SB: How do you measure your harness line length for your foiling sessions? 

After experimenting with line length from past sessions, in light winds, I use the SV Fixed 32“ for a more efficient upright sail position and in stronger winds, I choose fixed 30“ for more control.

SB: Do you ever set them differently for different conditions?

It’s important to try different positions until your feel comfy. My tip is to always make big changes and slowly move back to the middle and settle on the best adjustment. I like the feeling of hanging well down in them and having my arms slightly bent to give me room to react.”  

SB: How do you position them on the boom? Are there any on-water trimming methods you use or recommend?

I have the harness Velcro loops a bit looser on the boom at the beginning of my session so I can easily slide them. In lighter winds, I’ll position them close together (well within a hands width) and actually slightly more ‘backwards’ than comfortable, so constantly more front hand pressure and forward pull on the sail. In stronger winds, I re-fix them back again and set them further apart to counter balance the pull from the sail.”  

SB: How do you set your boom height for foiling and how’s that different from your regular freestyle set up? 

Compared to ‘fin’ freestyle, I’ll lower the boom for freestyle foiling to gain more control in my moves. Then, just like a normal fin board, I’ll tune the boom slightly higher if the wind drops to lighten the feel of the board, but it’s very small differences. I like the feeling of hanging well down in my lines and having my arms slightly bent to give me room to react.” 

Okay, so you’ve seen the videos and no doubt been beguiled by his brilliance and we’ve now discovered that Mr. Muller has some quirky tweaks you could try. Counter to his slalom teammates he uses longer lines in lighter winds and sets them slightly further back than regular fin freestyle to deliberately create front arm pressure. So we can ascertain that Balz won’t be overpulling and risk the line dropping out. Plus he wants maximum distance and some front arm pressure when setting up for moves that your physio would strongly advise against. But no harm in trying his set up and see what you think.

Harness Line Summary

To bring this all together…

  • Freeride Intro To Foiling: Harness lines slightly shorter (1-2 inch)than your fin Freeride.
  • Powered Freeride Foiling: Harness lines very similar to fin Freeride.
  • Race / Slalom Foiling: Same or even longer than regular fin race set up.
  • Freestyle Foiling: Similar to regular windsurfing, unless you’re Balz Muller.

Line Position: If you’re using dedicated foiling sails, the harness lines will be set marginally further forward than the equivalent windsurfing sails. 

To help you with recreational foiling set up and using something like the SV Alien and RedWing foil here’s a quick FoilWise summary. 

  1. For learning with inboard straps or on narrower boards have your boom shoulder to chin height when standing on the board.
  2. For faster blasting, wider boards and more outboard footstraps, set your boom chin-nose height standing on the board, especially if you’re at the level of foiling the board over.
  3. When learning or using very small sails in under-powered situations set your lines an inch or so shorter than normal windsurfing for your first sessions.
  4. Lengthen your lines to cope with larger rigs, more powered situations or when learning to heel the board and foil heavily over to windward to help you adopt a more sunken stance.
  5. Mast base further back to create more lift and great manoeuvrability.
  6. Mast base further forward to keep the nose down and make the board more directional.
  7. Choose a wider, deeper foil (1400-2000 Front wing) for learning, ‘Early Foiling’ and getting going on smaller sails.
  8. Choose a narrower thinner foil (750-1200) for faster speeds and controlling more powered up rigs.

Next time, we’ll look at getting the most out of your Alien & RedWing set up.

If you’re looking to get into windsurf foiling the pathway is now so much easier. For our FoilWise courses, we put sailors on SV Aliens and 2000 or 1400 Red Wing Foils. They are super easy to get flying on, incredibly stable and within a few runs everyone is in full flight. Here are a few shots of first day real life foiling experiences.

Ask Simon

If you have any questions about your harness lines or other aspects of your windsurfing, you can ask Simon @ Also worth joining a skill enhancing Windwise experience to get the most out of your time on the water and try some stunning Severne kit under the guidance of your personal coach! 

Windwise Winds Of The World Tour 2022-23

Freeride / Freewave / FoilWise 

Tenerife  + Bonaire + FeelViana + Alacati + Prasonisi + Mauritius + More

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