Sail Shape and Controls
USING SAIL CONTROLS FOR UPWIND SAILING Dinghies generally sail best and most efficiently when they are kept flat when heading upwind. When a boat’s crew weight can no longer keep the boat flat when sailing upwind, the sails should be flattened to reduce power. At the moment the crew weight can keep the boat flat again, the sails are adjusted properly. If the wind strength changes, use the sail controls to reshape the sails for optimal performance.
SPEED MODE/POINT MODE: The flatter the sail shape and tighter the leech, the closer the boat will sail, or point, toward the wind. The trade-off is that flat sails are not as powerful. If the leech is so tight that the top batten curls to windward, the sail will stall and slow down. If the situation calls for pointing high (for example, pointing above an obstruction), make the sails flatter. If pointing high is less important than going fast through the water, make the sails fuller.
FLAT WATER VS. WAVES: When the boat is sailing upwind in waves, it needs more power. When the water is smooth, the boat requires less power to move through the water. If the boat doesn’t need extra power in smooth water, it is good to flatten the sails and point high. As the waves build, it is important to put more power back into the boat by making the sails slightly fuller.
Adjustments to depower your sails include: • Tightening the outhaul • Bending the mast • Moving the jib leads aft • Putting Cunningham/downhaul on • Tightening halyards
Reversing these controls will power up the sails. MAINSHEET
The mainsheet performs two functions: • Adjusting the mainsail in or out • When sailing upwind, controlling the tightness of the leech
As the mainsail gets closer to the boat’s centerline, the mainsheet pulls down on the boom, much like the boom vang. Sailors need to be conscious of mainsheet tension so they do not tighten the leech excessively and cause it to hook to windward. End-boom sheeting has a greater effect on leech tension than mid-boom sheeting because of the end-boom lever effect. Mainsheet tension also affects your forestay tension; pulling hard on the mainsheet pulls back on the mast and thus tightens the forestay.
Table of Contents 17 TIP
ELeech tension directly affects the ability of a boat to point closer to the wind.
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