An adjustable backstay can be one of the most useful and impactful tools when it comes to de-powering your sail plan. However, it’s often overlooked and underplayed. Simply put, the backstay can bend the mast when tightened and straighten the mast when loose. Looking specifically at the mainsail, this can affect the fullness or draft as well as the twist of the mainsail.
It is worth noting that not all boats are capable of quickly tensioning or loosening their backstays. For instance, the Catalinas in our charter fleet are designed as cruising boats and have fixed back stays. However, a lot of sailboat rigs do include an adjustable backstay which can be tensioned or loosened quickly and easily. Within the OCSC fleet we have a number of designs that include an adjustable backstay: Olson 25s, J24s, J80s, and J105s.
When tightened, the backstay bows out the center of the mast, which pulls the luff of the mainsail forward, thus reducing the draft in the mainsail. A shallower draft reduces power in the mainsail. This can be a huge help in reducing weather helm.
Along with bowing out the center of the mast, the head of the mast is also pulled down toward the stern of the boat. The reduced distance between the top of the mast and the back of the boom loosens the leach of the mainsail, inducing twist.
Tightening the backstay not only induces mast bend, but can control forestay tension as well. A loose backstay will result in a loose forestay, which is often called “forestay sag.” Forestay sag powers up your headsail, helping your boat sail through chop. Reducing headstay sag will help your boat point and depower the headsail in stronger breeze.
Next time you stop by OCSC to charter a boat or take a class, ask one of our knowledgeable instructors or Club Managers to show you how to best use the backstay.