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The Parasailor and Parasail are patented and trademarked variants of a spinnaker sail for yachts. They were designed especially for cruising couples and short-handed crews, are easy to handle and well tempered. These sails make it possible to use one sail as spinnaker and gennaker while providing improved performance. It can be used between 70 and 180 degrees to the wind. Relieving the pressure on the bow and the stabilising effect of the Parasailor and Parasail improve the effect of the rudder and decrease the rudderthrows needed.
The Parasailor has a double-layer wing which inflates as the wind fills the sail. This acts like a soft batten, holding the sail out and actively re-opening the collapsed leech. The wing generates lift that raises the bow of the boat, and also ensures that there is no loss of propulsion. Thanks to this lift, any yawing by the boat is prevented, making a much more comfortable ride. Even if the Parasailor has collapsed after a sudden strong wind shift, the spreading movement of the wing supports the re-opening once the wind has shifted back again.
The Parasail was developed as a variant of the Parasailor, and is a great light wind performer. With very little tendency to roll, it is ideal for small crews. It can be used with a spinnaker pole but it is not necessary. The Parasail has a single-skinned wing as opposed to the double-layer wing of the Parasailor
Parasailor and Parasail Compared
|Boat Size||From Approx. 30 ft||Approx. 22 – 32 ft|
|Wing Type||Volume Wing (3D)||Single Skin Wind (2D)|
|Intrinsic Stability||Very High||High|
|Minimum Wind Speed||5 kts||3 kts|
|Works on Autopilot||Yes||Yes|
|Spinnaker Pole Required||No (but possible)||No (but possible)|
A tailwind fills the sail and propels the yacht forward. Part of the pressure escapes through the opening in the sail behind which the wing has been fitted in such a way that the air flows past, above and below it. Thanks to the shape of the wing and the angle at which the air flows towards it (with the angle optimised for efficiency), the air on the upper surface of the wing accelerates faster than the air flowing over the lower surface. The resultant increase in pressure on the lower surface compared to the upper surface causes the wing to lift, helping to stabilize the sail. The wing lift achieves two essentials effects:
- First, the pressure on the bow is minimized
- Second, propulsion increases because the wing's optimized angle of efficiency is designed so that the loss of propulsion caused by the opening is completely compensated for.
Benefits of the Parasailor and Parasail
- Can be set without use of a spinnaker pole
- Pressurised wing performs like a soft batten preventing sail collapse
- Aerodynamic lift from the paraglider type wing
- Gust venting (slots in the sail act like as a pressure relief valve)
- Reduces stress on rig
- Smooth opening
- Easy hoisting and lowering
- Suppressed yawing and rolling
- Great stability
- Easy handling even for short handed crew 
- "ISTEC Parasailor". Retrieved 23 August 2011.
- "Parasailor". Retrieved 23 August 2011.
- "Parasailor: An Agreeable Companion". Retrieved 23 August 2011.
- "Parasailor and Parasail Compared". Retrieved 24 August 2011.
- "Parasail: How The Wing Works". Retrieved 23 August 2011.
- "Parasailor Advantages". Retrieved 24 August 2011.