Shade sail

A shade sail is a device to create outdoor shade based on the same technology as a ships sail. Shade sails use a flexible membrane tensioned between three or more anchor points.

History

Ancient Egyptians and later the Greeks and Romans used large pieces of fabric to provide shade. The Colosseum in Rome was shaded with large canvas "sails" pulled into place by Roman sailors. Modern shade sails came into wider use with the invention of a far more durable and relatively inexpensive fabric called shade cloth. Useful versions of shade cloth appeared in the early 1990s especially in Australia and South Africa. For most of the 1990s there was some confusion about what these new devices should be called however they are now most commonly called shade sails throughout Australia, South Africa and the U.S.A. Most internet search engines will now provide good results for shade sails, this is a mark of general acceptance of the term. Shade sails have yet to have a significant impact in Europe and South America. A number of Australian shade sail businesses export to other countries. The shade sail industry in the U.S.A. is rapidly expanding, notably in the southwest. Rapid growth in the "shade sail industry" has seen many new businesses and websites offering shade sails and shade structures. Most recently Advice Only websites are providing useful shade information.

Current technology

Originally shade fabric, like all fabrics in the outdoors, suffered from UV degradation. UV inhibitors are now added during the manufacture of shade cloth and all good shade cloth now comes with a ten year UV degradation warranty thanks to this addition. It should be noted that shade cloth is a knitted fabric and this is an important factor is using it to design and manufacture shade sails.

Successful shade sail design uses the inherent "stretch" of the knitted fabric to create three dimensional shapes. Fabrics other than shade cloth are used to make shade sails such as PVC, a more expensive alternative, or canvas variations. The low cost of shade cloth and its ability to breathe makes it a prime choice for "cool shade".

To date there is no formal educational facility where shade cloth shade sail design is taught. The overwhelming majority of shade sail designers/manufacturers are largely self-taught. There are some principles borrowed from fabric architecture and related engineering. Shade sail designers/manufacturers' technical competence can vary considerably and some caution should be used in selecting a supplier. Because shade sail competence is experience based, evidence of a range of installations over some years is a prudent request.

Currently there are many thousands of ready-made shade sails being made in China and exported world wide. These are of limited value as truly successful shade sails are custom-made for a specific site. The ready-made shade sails usually have only 3 or 4 colours choices and 3 or 4 sizes whereas custom-made shade sails have an almost infinite number of sizes and 60 or more colour choices. Custom-made shade sails are also of a much higher quality and thus have greater longevity.

Installation

Modern purpose-made shade sails vary in shape, size and color and there is trend towards installing multiple sails, sometimes overlapping, thereby adding some form and style to its function. Shade sails are tensioned usually by means of either a stainless steel turnbuckle or a pulley system fixed at each corner of the sail. For permanently fixed sails, the turnbuckle provides the best means of fixing the canopy since it generally allows more tension to be applied. For sails that are used on an occasional bases, the pulley system is more practical since it can be set up and taken down in a couple of minutes.

References

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