Issue 319 - SEPTEMBER 2012
Guy Cribb Intuition
Double Words: Guy Cribb • photos: Guy Cribb and INtuition guests – Peter Corrigan in Maui and Lenka Slecna in Prasonisi
Shot Long before they bored me with logarithms I’d given up the will to live for maths, history and the sciences in school, and a subsequent series of fast exits from a number of establishments ensued. Funny that, considering Windsurfing INtuition has such a focus on the science of our sport.
tance and tuning- so intricately linked- could be written with basic physics or geometry, and this is often how I back up my message to INtuition guests after the more humane Muscle Memory sessions. I am generally of the thought, drive a car well but let the mechanics look after the engine. However, if there was a button I could switch in a couple of seconds that offered dramatic performance enhancement, then of course I’d be keen to tune it- for example if I could switch between traction or turbo, I’d be using it in and out of every corner. This month’s Double Shot feature brings simple geometry to your boom height and outhaul settings and reveals how harmonious they are with each other. By flicking the Double Shot switch you’ll turbo boost your early planing or create more traction control, radically broadening the wind range of any of your sails. The feature is also a rough guide to outhaul and boom height tuning- but not the full story, we’re looking more at their relativity this month.
Guy Cribb Intuition Outhaul Adjusting the outhaul alone can effectively increase or decrease your sail size by almost 15% – so if you have a 7m sail, you can basically turn it into a 5.9m or 8m. 7m sail -15% = 5.9m 7m sail +15% = 8m So if your quiver of sails were 9.5m, 7m, 5m, and 4.2m you would be very well equipped for every wind speed 10 – 50 knots - IF you were tuning them correctly, had the technique to back this up and did not have the specific needs of the wave sailor who demands more sails to handle the toughest conditions. Please refer to my recent Frigging in the Rigging feature about quivers/tuning (Windsurf/ guycribb.com).
Outhaul controls the power of your sail. Less outhaul makes the sail ‘fuller’ or ‘deeper’ giving you more power. So, less is more.
More outhaul flattens the sail giving you less power, so generally more control.
The maximum range of adjustment of your outhaul is about 25mm (2.5cm /1 inch). This tiny distance gives you the massive increase in sail power! If you’re underpowered let the outhaul off 5 – 10mm at a time until you feel more power. If you’re overpowered, pull the outhaul on 5 – 10mm at a time, until you feel less power. Simple stuff but how many times do you adjust yours? When we’re racing we have an ‘adjustable outhaul system’ that allows us to adjust our power and control whilst we’re sailing along! So might adjust it 30 times in a day! On an average days windsurfing I usually spend my first couple of blasts adjusting the outhaul to get it right – usually after 2 or 3 tweaks. Then if the wind changes, I adjust it again. Freeriders should experiment adjusting theirs around 3 times an hour. If not, you’re restricting your potential. There is no absolutely correct outhaul setting, it is purely circumstantial to the conditions, your ability and equipment. If you want more power you need to let it off, if you want less power you need to pull it on. Let’s keep it that simple for now, with a mental note that you will adjust yours 3 times an hour next time you go sailing. I could go into way more detail like how the outhaul effects leech tension for onshore wave sailing or free styling for example, or the oddity of overouthauling causing less stability, but not today, this feature is about the Double Shot. Please read on.
We have flexibility in our boom height for two reasons. 1. The disparity in heights of the rider, and 2. To adjust early planing or control (two opposites in windsurfing.)
Boom height based on your height
When you’re hooked-in and blasting in the footstraps, with your ass skimming the surface, if we measured the height of your harness hook from sea level, whether you were a 200cm or 150cm tall we’d find your hook was basically the same height, give or take a few cm. Since your primary connection to the boom is your harness hook and since everyone’s hooks are the same height, surely that means we should all have the same boom height? Certainly many professional windsurfers use the same boom height regardless of their actual height. (With exceptions for freestyling and some areas of wavesailing.) Strange, but true. I look forward to explaining this in more detail in future articles, but sadly not today. For now, please set your boom to 66% up in the boom cut-out for most sail brands – plus/minus 8cm if you’re extremely short or tall – but certainly nowhere near the 50cm range of difference of your actual height.
Boom height adjustment for performance
I use a varying boom height range of about 12 cm between my 4 and 8m sails – • To increase early planing, raise the boom. • To improve control, lower the boom. 82
Raising the boom takes the weight off my feet and puts it onto the mast foot, which is right in the middle of the board naturally trimming it flatter. When the board is flat it accelerates easier/faster. Lowering the boom increases weight onto my front foot, naturally pushing the windward rail into the water, giving me more control. It also naturally lowers my body, and the lower I am the heavier I am- improving my counterbalance to an overpowered sail. This point alone could be a whole magazine feature, but please just take it for granted right now – lower boom equals more control. In flatter water we generally use a higher boom and in rougher water a lower boom. Side-onshore wavesailing a slightly lower boom, racing a higher boom, the list goes on but the general adjustment is higher for power, lower for control.
So the story so far is – • Raising your boom improves early planing. • Reducing outhaul improves early planing. • Lowering your boom improves control. • Increasing outhaul improves control. Imagine if you could adjust both boom height and outhaul together in a couple of seconds, having an instant Double Shot effect? Well, due to the basic geometry of the rig, when you raise your boom height, you are naturally reducing your outhaul tension, and when you lower your boom it naturally increases outhaul.
Maths and science The general max range of outhaul adjustment from min to max is 3cm, 2cm is usually enough. The general max range of boom height adjustment is 12cm, but 8cm is usually enough. For every 2cm (20mm, 1/2 inch) of boom height adjustment you have 5mm of natural outhaul change- the recommended incremental adjustment. So if you raised your boom by 40mm (4cm, 1 1/2 inches) that automatically adjusts your outhaul by a staggering 10mm (1cm) which is basically the equivalent of giving yourself an extra metre of power! So next time you think about changing a sail size, think again, think Double Shot!
‘In 12cm of boom height change there is 3cm of outhaul change
The double shot switch
There’s three main opportunities to adjust your boom height: 1. Whilst blasting along come out of the footstraps and stand near the mast, quickly adjust the boom height and get going again without even getting wet. 2. If you’ve fallen off, during a waterstart you are right next to the boom so a quick adjustment is easy. 3. Come into shallow water and quickly make the change.
Summary Early planing- the high boom naturally released outhaul – note how the sail is so full it’s touching the boom? That’s great in underpowered conditions.
Control- the low boom naturally increased the outhaul and the sail no longer touches the boom.
I love the soft Muscle Memory approach to coaching, but there is even science behind that. When it comes to tuning, it’s physics all the way- please check out the Cribb Sheet for a non-fussy scientific approach to tuning.
Guy Cribb INtuition - Riding the World By Storm
The Cribb Sheet says it all.
©Guy Cribb INtuition 2012 Guy runs INtuition windsurfing courses attracting guests from all over the world for a week of radical development and fun only at the world’s very best venues from Australia, Brazil and Hawaii to Greece, Morocco and the Red Sea. The courses are always fully booked and have non-stop repeat offenders working their way up from waterstarting and footstrapping to riding massive surf in Hawaii. Guy transforms your windsurfing by day and shows you round the very best restaurants and local secret spots by night to give you a 24/7 action-packed INtuition experience that is incomparable to other holidays or courses. Guy is Britain’s Professional Windsurfing Coach, former multi-times British Champion and National Racing Coach. www.guycribb.com