Tuesday, 4 October 2011

Tune your boat for Racing

Sailing and Tuning Guide by John Greenwood
(NB. This information was prepared specifically for the 'Solo' class, but is good for most monohulls)
(NB. see also Steve Bourdow's Laser Clinic)

Four sailing / wind conditions that we shall consider :-
Sub-Powered 0 - 3 knts Force 0 - 1
Under-Powered 4 - 10 knts Force 1 - 2
Full-Powered 6 - 15 knts Force 2 - 4
Over-Powered 12 - 15 + knts Force 3 plus

The overlap between wind speeds is dependent on your rig, weight and fitness. For example a 16 stone helm with a soft rig and flat sail could be under-powered in 10 knts of breeze whereas a 10 stone helm with a stiff mast and full sail could be over-powered at the same wind speed.

Before setting any of the following information "in stone", get some feedback from your sailmaker or knowledgeable club or class members on the "look" of your rig and it's "match" to your body weight and sailing style.

Guidelines for boat set-up

Before racing check the following:-
  • All control lines & cleats work efficiently.
  • Mast on centreline of boat.
  • Foils in reasonable order with good fit in boat (leading edges of foils should be kept free from nicks, scratches etc.; 80% induced drag on foils comes from leading edge faults).
  • Mast heel to transom measurement 3.00m.
  • Mast rake to transom measurement 6.00m with ability to move mast +/- 2 cm (via forstay adjustment).
  • Shrouds set just tight when mast touches front of gate.
Variables to consider for each sailing / wind condition:-
  • Body
  • Mast rake
  • Chock
  • Traveller
  • Mainsheet
  • Kicker/Vang
  • Outhaul
  • Cunningham
  • Centreboard

Overall Objective

To make the boat easy to sail in order to focus our efforts, vision and enjoyment on the race.

Sub-Powered 0 - 3 knots ~ Force 0 - 1


To keep the boat moving ignore the marks, by that I mean don't point the boat in the direction of the next mark and wait for the wind to come. Look for the breeze use the shifts just as you would upwind.


Body Forward of thwart to retain maximum waterline length, to leeward to minimize wetted surface area.
Mast Rake Max. aft, touching aft edge of mast gate to promote more feel. With fuller sails need to extend forstay more to promote more mast bend and flatten sail. This will allow the leech to open and promotes air flow across the sail thus creating lift and hence more boat speed.
Chock Out. Putting the chock behind the mast reduces feel and promotes a lot of lower mast bend which is not always helpful.
Traveller Centered. Lock it up in the middle, it's simple and makes tacking easier.
Mainsheet Eased upwind to position boom up to 30cm outside corner of transom. If you try to narrow the sheeting angle too much the boat will feel stalled in these drifting conditions. Better to keep the boat moving and sheet in a little as speed increases.
Vang Slack to promote twist in the mainsail. This helps the air flow across the sail.
Outhaul Tight. Pull on to you get a single crease across the foot of the sail. This will open the leech of sail and promote air flow.
Cunningham Off, to keep max. draft of the mainsail at approx. 45%, i.e. just the mast side of half way between mast and leech.
Centreboard Start with the leading edge vertical to promote feel. (Get some friends to help tip the boat over on shore. Put marks on the top of the centreboard when the leading edge and trailing edges are perpendicular to the hull).


Body Keep relaxed. Position your body so you maximize the water-line length of the boat heeling to leeward and in a way that enables you to keep your head up, looking out of the boat.
Vang Off (as upwind). Consider putting some on to gybe to add a bit of bite.
Outhaul As upwind position.
Cunningham Off.
Centreboard The least you can - to keep the boat moving in a straight line. You actually need more than you think because you are always reaching in order to keep the boat moving.
Mainsheet Remember that the rudder is a brake and that you want to minimize your body movements. You should try and steer the boat with the mainsheet.
The sequence should follow mainsheet movement, slight rudder, mainsheet, rudder. Think of the rudder as the fine tune not the main steering device. Pull the mainsheet in to luff up and let off to bear away, using the rudder only to correct your actions.

Focus For Sub Powered

Keep the boat moving as a priority, don't automatically point the boat. Look at other boats around you to help your understanding of what is happening to the wind. Try taking a purchase from your mainsheet system or sheet directly from the boom to improve your feel of the pressure in the sail. Get comfortable, move smoothly and in a controlled way. Use your body and the hull shape to steer the boat. (To bear away heel boat to windward and ease mainsail - to head up heel boat to leeward and harden mainsail). Use of the rudder acts as a brake.

Under-Powered 4 - 10 knots ~ Force 1 - 2


Minimize the use of the rudder through the co-ordinated trimming of the mainsheet and movements of the body. Luffing up in the lulls, bearing away in the gusts.


Body On windward side of boat with constant pressure on sheets. Sit at or just behind thwart (get someone to tell you when your bow is just in the water).
Mast Rake Mid range i.e. tighten the forstay 1cm (2 holes) from the mast max. aft position. If we do not make this fundamental adjustment we will find that sheeting the main sheet harder to set the sail correctly will induce unnecessary weather helm and thus unbalance the boat.
Chock In. This will put more of the emphases on main sheet tension (helmsmen control) rather than mast type.
Traveller 8 - 10 cm below centreline, sheeting boom over inside edge of sidedeck and transom.
Mainsheet The mainsheet is your main speed control in all conditions, especially these. By sheeting too hard you can kill your boat speed and the boat will feel dead. By not sheeting enough you will not be able to point. The happy middle ground changes as the wind speed changes. To find it position the telltales on either side of mainsail at approx. 1/4, 1/2 and 3/4 height. These should be between 40 and 50 cm back from the luff. The correct sheeting of the mainsail is when the top telltale lifts slightly before the others. (I prefer this method to looking at leech telltales which I find difficult to read). At this moment the leech shape is described as being open, i.e. open to let the air off.
Vang Slack if you have a traveller, on enough to set the telltales (as Mainsheet) if you do not.
Outhaul Eased. Just enough to let the creases out.
Cunningham Eased.
Centreboard Trailing edge vertical.


Body Keep the weight on your feet not on your backside. Position your legs so that the pressure on your aft foot heels the boat to leeward and your front foot can bring the boat upright again.
Outhaul When running as upwind, reaching ease a little to let the crease out along the foot of the sail.
Cunningham Off.
Centreboard As sub-powered. If you need to make ground to leeward e.g. to get an overlap consider taking the centre board right up to slide sideways. When your doing this use your body weight to correct the "crabbing" of the boat.
Mainsheet As sub-powered with the addition of body movement into the trimming/steering sequence. To steer and trim the boat, the sequence is now mainsheet, body. The mainsheet movement now acts as fine tune and the rudder shouldn't really need to be used at all. I sheet the mainsheet direct from the boom on a 2:1 purchase i.e. I grab the front downward lead coming off the boom. I find this gives me a smoother movement and most control over the boat.
Vang As sub-powered for gybing. As wind increases pull on gradually - less is best.

Focus For Under Powered

Be smooth. Use Body weight to steer the boat minimizing rudder movement. Look for more wind on the water. Begin to concentrate on pointing. Do not pinch, keep boat flowing. Get the mainsheet setting right and then remember what it feels like. Keep it feeling the same and look at the race not the mainsheet. If the feeling goes, look at the sail again.

Full Powered 6 - 15 knots ~ Force 2 - 4


To find "the groove". To race the boat to your maximum physical and mental potential. To understand the options available and not available at any moment in time and to select those that most effectively contribute to meeting your pre-defined goals and objectives.


Body Hiking comfortably and within yourself: do not get stressed or over tired, it's not a hiking competition! Set the boat up so you are comfortable and can concentrate on the racing. Do not hike too far aft, get some feedback as to when your bow is just in the water to maximize waterline length.
Mast Rake Forward in the range (Rake 6m+) i.e. tighten the forestay 2cm (4 holes approx) from max. aft.
Chock In front. Hard in. Do not worry if your mast bends backwards slightly without the sail being rigged especially if your mast is a bit softer than one ideal for weight and sailing style.
Traveller 8-10 cm below centreline. Position boom over middle of side deck at the transom.
Mainsheet Mainsail leech closed (relatively). All three telltales lifting at the same time. Ideally the top one should always lift a little earlier than the others but just a little.
Vang Off, or if no traveller then set telltales as above.
Outhaul Pull out to put creases back in.
Cunningham May need to trim a little to maintain max. draft at optimum 45%. If your sail is old you may need to pull a bit harder.
Centreboard Trailing edge vertical for speed. Leading edge vertical for pointing. Vary according to what you want to do at the time.


Objective - Fast and low. SPEED, SPEED, SPEED.
Body Fluid body movement co-ordinating mainsheet and the tiller movements. Position yourself so that your hips are always further inboard than your shoulders. Lock your feet and legs in a position that enables you to move your backside if you need to. You should feel locked in position (solid) from your hips down and fluid (flexible) from the waist up.
In this wind condition the boat should be kept perfectly upright when reaching and heeled to windward on a run until the helm is neutral.
After some practice you can steer the boat on a run with your shoulders & mainsheet movements. Mainsheet out (ease main a little) to bear away, sheet in a little to luff up.
By twisting your hips so that you are facing "half forward" you position your head in such a way that it makes it easier to see the waves, gusts and the race.
Your body positioning is the absolute key in these conditions if you are to evolve your style and technique to the extent that lets your body sail the boat and your mind race it.
Outhaul Off, to open the lens of the sail. This will vary by sail manufacturer, however, in all cases look to just drop the creases out of the foot, so that it offers an uncreased full shape.
To avoid letting the outhaul off too much, tie a knot in the system at the inboard end of the boom. This allows you to un-cleat the outhaul as you bear away round the windward mark and immediately begin to concentrate on your body positioning and the race.
Cunningham Off
Centreboard Half way up. If you are trying to steer the boat without the rudder on the run by co-ordinating shoulders and mainsheet, then less centreboard makes me feel less secure and less confident.
Vang As the mainsheet is your main speed control upwind so the vang becomes your speed control off-wind. I mentioned earlier that you need less than you think. This is because of the soft masts and floppy rigging that nearly all Solo's use today - (even a Superspar M7 cannot be considered a stiff spar). What happens, as you pull on the vang to trim the mainsheet, is that the mast bends and de-powers the sail. You therefore have to trim the vang to the overall sail shape not just the leech shape as in other boats.
By pulling on the vang until the luff tell-tales fly at the same time, you should be in the correct ball park. If in doubt, ease it off a bit.
Mainsheet As under-powered.

Focus For Full Powered

Sheer enjoyment, sailing at its most comfortable and rewarding. Let the boat flow and concentrate on how the boat feels. If it begins to feel dead, ease the mainsheet a fraction. If the wind increases momentarily, pull the mainsheet on a bit and feel the boat "squirt" forward as you hike a little harder to keep the boat perfectly upright. If you hike out hard as you can or feel that the extra effort does not fit into the days plan, pinch a little during the gust to keep the boat upright. Keeping the mast perpendicular the water helps the centreboard at its maximum efficiency as well as reducing the amount of rudder you need to use to keep the boat sailing in a straight line.

Over-Powered 12 - 15+ knots ~ Force 3+

Warning - The change from being fully powered to being over powered can happen very quickly. The effective management of the transition can lead to significant improvements in performance and hence your enjoyment. Control movements are made progressively and sequentially "in a spiral" as wind speed increases over and above your fully powered maximum.


Keep upright. Be confident. Go fast and have fun.


Body Keep relaxed, hike a little further towards the middle of the thwart and the aft edge of the centreboard case as a chop develops.
Mast Rake Middle of the range, ease 1cm (2holes) from full power position. Mast rake should be approx 6.00m
Chock If the wind has increased dramatically during the race and you become overpowered remove the chocks. If you are rigging for over powered conditions - keep the chocks full in. This will support the bottom of the mast and direct the effect of the vang to the middle section of the mast where it will have a greater effect.
Traveller Eased progressively down the track from full power position. (see depowering sequence).
Mainsheet Keep easing it when the gust hit to keep boat upright. Often you find you can't do this quick enough so pinch a little at the same time.
Vang Pull on to take up downward component of mainsheet as soon as boat starts to heel and luff up. This means that when you let the mainsheet out, the boom does not move up but simply out parallel with the deck.
Outhaul The first adjustment you make whenever you feel as if you are constantly overpowered; pull hard on so that creases appear in the foot of the sail.
Cunningham Look at the sail shape after other adjustments and trim to optimize max. draft at 45%. The last sail adjustment you make after pulling on the outhaul and the vang.
Centreboard Move from trailing edge vertical progressively to 3/4 up. (See de-powering cycle).


Body As full-power but further back in the boat.
Outhaul On - no need to ease it.
Cunningham On for the reach. Off for the run.
Vang Use less than you would for fully powered.
Mainsheet Over trim slightly by sheeting to the top tell-tale.

Focus For Over Powered

Keep the boat upright, anticipate changes in wind speed, up and down. Trim through the cycle 1-10 to depower the boat, reverse the order to add power to the boat as the wind speed drops.
Focus your attention on how the boat feels. You are trying to create a power level from the variables under your control that matches the available power with in your own body. If you feel strong add a little power. As you get tired trim the boat to match that feeling.

Always plan to be in control. Set the boat up to work within your own physical capabilities AND HAVE FUN!


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