We chose our own seam tape with very strong and durable adhesion and does not suffer from contact with water or UV light.Don't worry about this page too much for now. Also at the clew and tack, the joining panels widen again to overlap and create the reinforcement by the panels itself rather than needing all reinforcements being stuck on. Like this the seams actually work as tendons. The batten pockets are made with overlapping panels, creating a symmetrical sail shape and giving a double seam for extra strength without costing extra weight.Īll important seams are double and running along the stress lines and are not put across stress lines for optical reasons. There is lots of Kevlar X-ply and all panels are layed out into the forcelines, similar to membrane sails but less cost intensive, much more puncture resistant and easier to repair if necessary. We are experienced sail makers with many years of repairing sails.
THE CONSTRUCTION IS ABOUT THE BEST POSSIBLE Use the lower eyelet for more loose leach (powered up blasting, B&J, cross off shore wave riding) or the top eyelet for a tighter leach for cross on shore riding, where you have to bottom turn going clew first. Using both eyelets ( see rigging manual) will give the average setting. In the clew there are 2 eyelets offering more tuning options. So the total wind range that a typical sail range of 3.7-4.2-4.7-5.2 covers, is bigger than with sails that are all cut the same. In higher winds, you don´t want to have to use a too small a sail either so with each size down, the profile is reduced a bit. Not only does being able to use a smaller sail save weight but also gives you a stronger rig. The smaller the sail the less loading a wave can put on the sail and a smaller sail exerts less leverage on your mast and boom, it’s a win win situation. In this way a smaller biggest sail can be chosen. THE PROFILE DEPTH MORPHS THROUGH THE RANGE, THE SMALLER THE SIZE THE LESS SEAM SHAPE AND THE MORE BATTEN ROTATION. Therefore you can rig a smaller and lighter sail with a shorter boom giving more manoeuvrability and liberty to move the sail more and faster in turns. The higher aspect ratio also makes the sail more efficient for its surface. As the mast pocket lines up with the sail at all times, there is increased efficiency and soft batten rotation throughout the settings range. As the profile stability is held by both seam shaping and batten profiling there is a very good top end control, even when set full. As the battens them selves want to become straight, the sail still depowers very well. There is good low end power as the battens are halfway pre-bent. Witchcraft sails are designed to use a combination of both seam shaping and batten rotation to create the best of both worlds: Sail rotation is also harder and power delivery more jerky. When set flatter, a sail with only seam shaping has the batten tips not lining up with the mast pocket, creating a bump on the leeward side creating a loss of power. Also the stability does not only rely on the batten profile but also by the shape of the sail itself with a higher top end as a result. As the shape is always there, the battens are derotated all the time, the sail does not depower well and drags more when going down the line. Seam shape pre-bends the battens and has more low end power as the wind does not need to bend the battens to get shape. When set full, a rotational sail can be hard to rotate and become even more unstable, also the mast pocket does not line up with the sail well anymore, losing efficiency.Ĭontra: depowering and drag down the line Also the stability of the sail then relies only on batten profiling, with a reduced top end control as a result.
But, as battens them selves want to stay straight, such sails require more wind to power up. Pro: Depowering and less drag down the lineīatten rotation allows the sail to become flat without wind so the sail can depower when needed. Wave sails can get shape either through batten rotation or seam shaping. Or better said: mast length is more important than boomlength or surface. The first 1/3rd of a foil delivers 2/3rd of the power. So important to keep the lee side smooth. The lee side of a foil delivers 2/3rd of the power. a sail converts wind into power by bending the airflow.
A BIT OF SAIL THEORY There are a few basic guidelines for sails (or any foil really):
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