jackstay

A jackstay is a type of temporary rigging used in sailing and other maritime contexts. It is essentially a rope or wire that is tensioned between two points, such as the mast and the boom, or between two points on a deck. The primary purpose of a jackstay is to provide a secure handhold or a point of attachment for other equipment.

In sailing, jackstays are commonly used to secure sails when they are furled or reefed. The sail is wrapped around the boom or mast, and the jackstay is then passed over the folded sail to keep it tightly bound. This prevents the sail from flapping in the wind and becoming damaged. They can also serve as a safety line, allowing crew members to clip onto them with a safety harness when moving around the deck in rough seas.

Beyond sail handling, jackstays can be used to support awnings or covers over a deck area, providing shade or protection from the elements. They might also be used to guide the movement of other ropes or lines, ensuring they run smoothly without snagging. The tensioning of a jackstay is crucial for its effectiveness, and various methods are employed, including turnbuckles or simple knotting techniques, depending on the required strength and adjustability. The term "jackstay" is also used in some industrial contexts for similar tensioned cables.