Anti-torsion cables are an essential piece of kit for top down and straight luff (bottom up) furling systems.
Top Down Anti Torsion Stay
As the name implies, top down furling needs to start from the head of the sail. The rotation of the wheel at deck level needs to be efficiently transferred to the head. Anti-torsion cables are specifically designed to resist twisting - the better the cable, the less turns required at deck level to rotate the upper fitting. A Harken Reflex Cable has the highest torque resistance making it ideal for top down furling Summary of Required Properties: ultimate anti torsional resistance, maximum diameter : weight ratio, good strength
Straight Luff (Bottom Up) Anti Torsion Stay
Bottom Up Furlers rotate the tack and head simultaneously so also require cables with excellent ant-twist (torsion) properties. Straight Luff Reaching Headsails also rely on the cable for luff tension. Anti Torsion cables for bottom up furling need to be both strong and low stretch. The Harken Reflex cable is not suitable for this application unless supported by an additional dyneema line Summary of Required Properties: Very strong, low stretch, stiff, thin, light, good anti torsional resistance