As the wind increases keep tightening the backstay to bend the mast and flatten the mainsail. As a general rule start with little or no backstay in light conditions to have the sail full and powerful. On boats with running backstays with deflectors or checkstays this does the same thing. In lighter winds with a straight mast you can create a very powerful mainsail but as soon as the breeze increases the sail needs to be flattened not only with outhaul but also by tightening the backstay. Mast Bend (backstay tension, spreader angle / rig tension)Īs we know a fuller sail is more powerful so this can work as much for your boat speed as it can against you. With the sail now flatter, there is less distance between the leech of the jib and the mainsail (commonly referred to as the ‘slot’) – the air can now pass quickly through both, reducing drag & creating less disturbance on the mainsail….again adding speed! Secondly the reduced exit angle allows the accelerated air to exit quicker which reduces rudder load and therefore weather helm…thus reducing hydrodynamic drag. This achieves two primary functions, firstly with the sail becoming flatter there is less drag so therefore the aerodynamic profile of the sail becomes more efficient and the boat goes faster. As a general rule at the lower end of your sails range you will have the Outhaul eased to keep the bottom of the sail more powerful.Īs the wind increases and the boat no longer needs all the power the Outhaul is gradually tightened to flatten the foot. Different conditions will see you treat the Outhaul differently. The outhaul position on most boats adjusts foot tension on the sail. As soon as the wind increases and the sail loads up remove the wrinkle and continue to add luff tension as the sail moves up its designed wind range.Īvoid over tensioning the luff before checking with sheet tension as this will add to the life of your sail. In light conditions a few wrinkles on the luff of your sail is ok, but too much tension could see the sail have a distinctive ’knuckle’ in the front. Factors that contribute are stretch, mast bend (via backstay or mainsheet load) and also mast setup including spreader angle and rig tension. This is largely due to the sails maximum draft moving back as the sail loads up. Your designer will have designed your sail with particular maximum depth, maximum camber position (draft), entry angle, the wind range of the sail, the material used in your sail and the amount of mast bend you will encounter (with varying backstay tension).Īs a general rule the more wind you have the more luff tension you should apply, particularly when sailing hard on the wind. Luff Tension - Halyard & Cunningham (downhaul) Calibrating your boat is very important for your on board reference and also to record later in your OneSails Tuning Diary Take tape and marking pens with you when you sail.Make sure the sail is used in its designed wind range as taking the sail outside the range can lead to premature aging or even failure in extreme cases.Regularly check all telltales and leech ribbons are in good order – without these trimming is difficult.If the sail has a bolt rope inspect and service the top part to ensure smooth feeling into the foil.If your sail has slides or luff cars lubricate them every 6 months to prevent corrosion. ![]()
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