Cruising sail : headsail (tri-radial)
Kemp Sails

With radial sails, you can bring the panels into line with the stress pattern. This way, the loads run through each panel at a relatively constant angle, instead of crossing them at different angles as they do with a cross-cut sail. You can see from the diagrams on the other side that this works better with tri-radial designs (panels radiating from head, tack and clew) than with bi-radials (head and clew only). But there’s a potential problem: since the warp threads (along the length of the panel) tend to stretch more, is there really a net gain?

The answer is no, not really - unless you use what’s known as a ‘warp-orientated’ fabric, which is specially woven with a greater number of stronger warp threads in relation to the fill. Only then can a tri-radial sail give you a better, more stable and longer-lasting shape. That’s why, for our radial sails, we only use warporientated cloths - of which there are currently only a handful in woven form. With laminated fabrics, you have a much wider choice. Either way, cloths suitable for tri-radial sail construction are more expensive - which is why some sailmakers still quote for radial sails using cheaper, fill-orientated cloth. It may make the quote look attractive - as though you’re getting a ‘high-tech’ sail at a relatively low price - but we won’t compromise our sail construction in this way. As ever, it’s important to compare quotes on a like-for like basis!