Windwise: Winter MOT with Simon Bornhoft - Boards Windsurfing

Windsurfing Magazine



Windwise: Winter MOT with Simon Bornhoft

Even if spring has well and truly sprung, it’s still a good idea to have a tinker and a tune with your kit. So lets look back at Simon Bornhoft’s essential tuning and MOT-style checks…

Given the variance in windsurfers’ stature and ability, you’d expect kit set-up to be wildly different. However, set-up has actually become rather more standardised in recent years. So – until the next random change in kit design – here’s a comprehensive check list to assist your potential. While one component alone might not make that much difference, the combination of all these fine tuning tips will contribute greatly to your enjoyment and performance on the water.

You only have to do this once to ensure a whole year of great gear set-up!



You want the fin to provide early planing power and upwind performance, but no control difficulties. So use these size guides, then fine tune to suit your exact needs.

Recreational ‘freeride’ boards of 115-180L

Take your sail size, multiply by 5 and add 4 to find your approximate fin size in centimetres (e.g. 7m x 5 + 4 = 39cm).

Recreational ‘freeride’ boards below approximately 115L

Sail size x 5 + 2 = approximate fin size in cm (e.g. 5m x 5 + 2 = 27cm fin).

Freestyle-wave, crossover and waveboards of 75-100L (and freestyle boards being used for more general sailing)

Sail size x 5 = approximate fin size in cm (e.g. 5m x 5 = 25cm fin).

INCREASE fin size by approximately 1-5cm if you sense any of these points:

• Underpowered, slow to plane, difficulty staying upwind or spinning out a lot.

• You’re over 85kg or sail too heavily on the back foot.

• For exceptionally large rigs (8.5m+) or very wide boards (70cm+) you could increase fin size by up to 10cm.

DECREASE your fin size 1-4cm if you sense any of these points:

• Overpowered or windward rail lifts excessively.

• No worries early planing or staying upwind.

• Under 70kg or nice and light on your back foot.

• Your freestyle requires a tiny fin for spinny moves.

Service Check

Sand down scratches and chunks out of the fin as these cause spin-out and loss of speed.



For ‘freeride’ boards with flat rockerlines position the front straps towards the windward rail, and use the double back strap option. This is particularly relevant if you have a wide-tailed board or you’re using a fin over 30-32cm. The whole of your little toe should poke through the footstrap. Curl those toes up to lock the windward rail down:


For narrower-tailed crossover/freestyle-wave boards use inboard front and single back strap. Not as comfortable for straight blasting, but far more productive for out of the harness moments like jumping, riding and especially for freestyle. For waves and freestyle open the strap so the whole arch of the foot can go in:

Service Check

Avoid twist by screwing straps in tightly. Make sure the whole of the little toe pokes through with boots on.

Mastbase Guide:

Apart from transitions, the rest of the time we want to keep that board flat. The recommended distance from tail to mastbase is actually very similar on all modern boards, so get a marker pen out and check that the centre of your mastbase matches these guides:

Freeride Boards 115-220L

Average centre of mastbase position – 135cm from the tail.

Freeride Boards 95-130L

Average centre of mastbase position – 130cm from the tail.

Freemove, Crossover, Freestyle, Freestyle-Wave & Waveboards 75-95L

Average centre of mastbase position – 130cm from the tail.

Track Tuning

Shift the mastbase forward (1-5cm from average) if the tail is sinking, the board is bouncing, constantly luffing, or if using max sail size for that board.

Shift the mastbase back (1-5cm from average) if the nose ploughs into chop or you want the board to turn more tightly.

Service Check

Foot protectors are great, but do ‘lift the skirt’ in case the UJ has any rescue enhancing qualities.

Ding Dong!

Regularly fill dings, cracks and stress points, otherwise your board will take on water!


Planing Boom Height

After banging on for years about using the back of the board as a guide for boom height, I’m glad to see that the technique is now widely used. For the majority of sailors between 5’7” and 6’2” the underside of the boom sits just off the back of the board (within a 5-10cm range).

5’0”-5’7” sailors: Underside of boom sits within 0-10cm inside the tail.

5’7”-5’9” sailors: Underside of boom sits from 0-10cm past the tail.

5’9”-6’5” sailors: Underside of boom sits 0-15cm+ past the tail.

Simon Says…

On wide boards (65cm+) raise the boom higher than you’d normally place it, to allow for the extra commute outboard.

For extra control in overpowered situations, waves, moves and freestyle you can drop the boom (1-3cm) compared to your blasting / freeride setting.

In non-planing situations (when you’re out skills training!) sail with it at top of shoulder to chin height.

Service Check

If there is one piece of kit that can transform the rig, it’s the boom. Modern alloy integral ‘wide front-end booms’ now provide incredible stiffness and great value. It’s well worth an upgrade if your current boom flexes, moves or twists.

Tape Up

While you’re there, put some tape approximately 80cm past your rear harness line

as a reminder to move the back hand for gybes and clew-first moments.

Service Check: Replace tired inhaul and outhaul lines.


Downhaul Trick

Here’s a great trick to get sufficient downhaul on – and it also doubles as a neat way to get close to your maximum downhaul setting.

Rig your sail and extend the mast extension and boom length slightly more than recommended settings. Attach the downhaul, but don’t apply it

Pull the outhaul, by hand, pretty much as far as it will go. (If you’re a giant, don’t massively overdo it. If you’re of smaller stature or strength, put your foot on the boom and give it a decent pull.):

The battens should pull away from the mast and the outhaul will stretch excessively tight. You should find that it is far easier to apply the downhaul and the leech has fallen away down to the 3rd or 4th batten. This should take you very close to what could be described ‘maximum downhaul’:

Downhaul until the clew eyelet area goes slack, or at least loses most of the outhaul tension. It’s surprisingly accurate at taking your sail close to its maximum downhaul setting. Now undo the outhaul and fine tune the sail. You’ll find from this ‘max downhaul’ point you rarely need to let off more than 1-3cm downhaul to reach your minimum setting. Once you’ve settled on exact downhaul, you should only need 2-5cm of outhaul.

Write On

As we know, when it comes to weights and measures, manufacturers aren’t always that accurate. Not all ‘430’ masts are 430cm, not all ‘25’ extensions are 25cm. Plus, over time many boom and extension markings get worn off, so when you have to use an extension or boom on different sails it can be hard to recall what setting it should be. So once you’ve found your preferred setting for your rig, get a permanent marker pen and write on the clew and foot of the sail the number of holes or rings showing in the extension or boom. For instance, on the clew write ‘B15’ (this would mean blue boom, 15 holes showing). Makes for far easier and quicker rigging.

Service Check

Wash, then dry off your sails if you’re going to be storing them for any length of time. Let batten tension off too, but remember to put it back on when you use the sail again. Replace knackered downhaul lines.


As Ian Leonard quite rightly wrote in a recent feature, not all 28 inch lines are the same length! To add to that, I’d like to recommend you don’t buy on length of line or trends. Forget line length! It’s the length of your arm that counts. Don’t let anyone tell you that you need 28s, 30s or whatever. We all have different length arms, so measure the line for your arm and fine tune to suit your ‘style’ of windsurfing.


The velcro fixings should be no more than a hand’s width apart.


Place the very tip of your elbow in the line and tension it.

Elbow to ‘chicken bone’ part of palm with longest setting elbow to ‘blister pad’ part of palm. Blasters will adopt a slightly shorter line than freestyle and wavesailors.

Seat Harness

Line should be elbow to watch strap, with longest setting elbow to ‘chicken bone’ part of palm.


I’m going to stick my neck out a bit here, but I’m now convinced that ‘skinny’ masts are the way to go on sails below 7.0m. So unless you’re a full-on racer / blaster loading your rigs to max power all day and have no interest in quick waterstarts, lighter swing weight in gybes, tacks and transitions, then it’s worth switching to narrower diameter masts. Their actual weight is no different, but the rig’s feel, water release, rotation and swing weight is so much better due to the derotating luff. I was stubborn to change, but if I had a windsurfing centre I’d use skinny masts throughout, such is the response from 99% of clients who try them. I’d recommend making narrow diameter masts part of your long-term plans.

Service Check

Check out for major knocks or dents, this is where the mast will break. Check the head cap is tight to prevent water and sand jamming the mast.


These are just guides – you must fine tune on the water!

Rule of Hands

Count the number of hands down the boom to match the sail size. Five hands for 5.0m, six hands for 6.0m, etc. Suits marginally powered days, but has its flaws due to varying hand sizes, so not ideal:

Rule of Thirds

Run a tape measure from the clew to the middle of the mast. The rear harness line fixing goes one third of the way down the boom. Tune by moving front line forward or back. Favours high boom and very powered up ‘slalom style’ sailing, evolved from racing days. Lines very often end up slightly further forward of this guide:

Rule of Surprising Accuracy

Okay, it’s been nearly two years of trials on courses, seminars and demos, and this is a quick, easy way to pre-set the lines before going on the water (for non-cambered sails below 8.0m).

1. Out of the wind, hold and lift the boom with one or two fingers.

2. Take time to find the balance point – so that the boom is perfectly horizontal when you lift it.

3. Fix your harness lines just either side of that point.

This usually works out to be between the Rule of Hands and Rule of Thirds. Depending on wind strength, fullness and style of rig, it will require fine tuning by an inch or two on the water, usually forward slightly (lighter winds) or back (stronger winds). Try it and see how it goes!:


Newsletter Terms & Conditions

Please enter your email so we can keep you updated with news, features and the latest offers. If you are not interested you can unsubscribe at any time. We will never sell your data and you'll only get messages from us and our partners whose products and services we think you'll enjoy.

Read our full Privacy Policy as well as Terms & Conditions.