Cruising Mainsail: Tri-Radial Spectra

Martin 49 Tri Radial Spectra web — *A Martin 49 with a tri-radial Spectra performance cruising main and roller furling jib.*

image a94f058e 10d5 4389 966f e9bb80e097db — Radially panelled sails use”warp-oriented” cloth where the strongest yarns run the length of the narrow panels as shown by the thin grey lines. For clarity, the diagram only shows thread lines of the panels in the back half of this sail.

Tri-Radial mainsails constructed with a Spectra laminate are the perfect choice for big boats that want performance sails, yet need more longevity than a membrane sail. Spectra is one of the world’s strongest and lightest fibers. Pound-for-pound, it is 10 times stronger than steel and up to 40 percent stronger than aramids. Spectra doesn’t breakdown from folding, is impervious to UV radiation, and gets softer with use.

The Spectra yarns used in radial sails have tremendous strength in the warp direction.

Cloth manufacturers make many styles of Spectra laminates for boats from 40-150 feet long. Some have more and some have fewer Spectra yarns, while for the mega yachts, Carbon inserts are also used. Most of the cruising Spectra laminates have taffeta on both or one side of the laminate.

Cruising Spectra laminates come with one or both sides covered with finely woven polyester taffeta, which improves chafe resistance.

Radial sails (with their many panels) allow sailmakers to use more than one laminated fabric in a sail. Stronger laminates can be used in high load areas like the leech and tack, while laminates with less strength can be used in the luff of the sail. Using these materials helps reduce the weight and price of the sail.