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RADIAN... the world’s first high-performance warp-oriented woven polyester sailcloth

© North SailsFor decades, polyester (Dacron) fabrics were woven with straight FILL yarns encapsulated by “up and over” WARP yarns. When building a crosscut panel layout sail, cloth of this type is the established best choice. However, “fill oriented” fabrics are not suitable for radial sail construction, where the length of panels exceeds the width of commercially available sailcloth rolls. Until now, the solution for radial sail construction was to laminate the fill-oriented woven sailcloth with Mylar film to improve strength in the warp direction.

Given the inherent limitations of looms and sailcloth-grade polyester yarn, weaving high-density polyester cloth with straight and highly tensioned warp yarns has been a difficult challenge. There are “warp” polyester styles already in the marketplace, but they are loose constructions that compromise both warp and fill performance. This tradeoff is not acceptable if the goal is to produce high performance radial cruising sails.

Starting with a now patent-protected concept, a clean slate, and a healthy dose of patience during over three years of trials, North Cloth has combined unique materials and a novel manufacturing process to create Radian... the first warp-oriented polyester sailcloth in the industry suitable for radial panel layouts. The clear benefit of radial panel layouts can now be applied to a whole new class of cruising and one-design sails.

What does Radian mean to you? Now you can buy a load-aligned radial sail that performs better and holds its shape longer without sacrificing the easy handling and mildew resistance of woven sailcloth.

Radian comparison

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Premium NorDac
This SME (electron microscope) photo shows North Premium NorDac, a high quality FILL-ORIENTED woven polyester with the tightest possible construction. Well established yarn and weaving techniques result in straight FILL yarns encapsulated by the "up and over" warp yarns. When building a crosscut panel layout sail, cloth of this type is the established best choice.

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NorDac Radian
While WARP-ORIENTED Radian looks similar to tightly-woven Premium NorDac, the fill is rotated 90 degrees. You can see Radian’s straight, un-crimped WARP yarns surrounded by a dense, tightly woven fill yarns.

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Other warp-oriented fabric
Currently available WARP-ORIENTED fabric shows loosly woven construction that compromises on performance in both the fill and warp direction.

Lab tests for NorDac Radian are notable in several ways. It has superbly low stretch, but it is in the ratios of stretch amongst the warp, fill and bias where Radian excells compared to any other commercially woven “warp-oriented” Polyester sailcloth.

Radian is available in five weights: 4.9oz., 5.6oz., 7,2oz., 8.2oz. and 9.4oz. Radian Oly (with a stiffer finish) is available for one-designs.


Tanzer 31 with Radian mainsail and jib© North SailsRadial panel layout with horizontal shaped seams for mainsails and genoas
Stainless steel rings
Webbed head & tack loops (for roller furling genoas)
Extended TEARDROP corner patches (for roller furling genoas)
Adjustable polyester leechline and footline with aluminum leech cleat (depending on luff length) and grommet foot cleat
Epoxy fiberglass battens with Velcro closure batten pockets (Mainsails)
Cunningham adjustment
Loose-footed mainsail with adjustable leech and footline
Telltales, spreader patches and drawstring sailbag


VB+™ Vertical Battens
Batten Hardware
TuffSeam™ seam protection
Sail numbers and/or insignia
Draft stripes
In Boom Furling Construction
SailKote Anti-Mildew Treatment


VB+™ Vertical Battens
Telltale windows
TuffSeam™ seam protection
Webbing Head and Tack Loops (for RF Genoas)
Sail numbers and/or insignia
Rope Luff Pad or Foam Luff Flattening device for roller reefing
Draft stripes
UV protection
Soft Clew
Soft Hanks
SailKote Anti-Mildew Treatment