This mainsail is for boom spinning. The tri-optimal cut will correctly distribute the force of the wind that acts on the sail, and also sets the optimal and stable sail shape. The shape of the sail is retained for several years. This sail can be ordered in several types of materials, where the base polyester laminate guarantees an efficient and long service life. If you are looking for an extremely sturdy sail, a woven dynema (radial mesh) is the best choice. The through horizontal battens define the shape of the sail and help to twist correctly into the mainsail. The lower battens keep the sail in the correct shape if the mainsail had to be reefed..
An x-cut sail consists of a series of horizontal sashes, parallel to each other and perpendicular to the leech. This is a reliable and fairly cheap method of manufacturing; the sail is affordable and durable. In fact, the cross cut is the ancestor of sailing design and sails with this cut have a proven track record.
Cross cut sails are usually made from woven polyester fabric with weft threads that are stronger than warp threads. The canvas is oriented towards the direction of the load, resulting in a very strong sail.
Tri-optimal cut, also known as radial cut. The sail is sewn from radial pieces that are oriented towards the corners of the sail. This arrangement optimally distributes the forces that act on the sail and helps to maintain the correct sail shape. Pieces of fabric for radial cutting are laid out and stitched according to the load diagram, providing strength and stable sail shape.
Upwind sails with a trioptimal cut are usually made of "laminate" - a fabric made up of several layers. However, there are sails with a radial cut made of polyester fabric, for example, most nylon sails for full courses are tri-optimal cut.
The unique and patented EPEX membrane technology is the flagship of Elvstrøm Sails. 100% custom design in which each power fiber is positioned according to the load diagram. Each sail is calculated by a special computer program according to individual preferences. This ensures absolutely optimal fiber distribution throughout the sail, resulting in exceptional shape stability and maximum recoil.
A wide range of materials and fibers are available to suit any need. All air between the layers and the power fibers that make up the sail is removed by vacuum and the entire canvas is “baked” into a single whole.