Jackstay

A secured line, wire or webbing arranged to guide, support or provide attachment for people or equipment aboard a vessel.

On yachts, deck jackstays commonly run fore and aft so a clipped-on crew member can move while remaining attached. The same word also has rigging and working uses, including supporting sails or guiding equipment, so material and direction are not fixed by the term alone.

A personal-safety jackstay is a complete load-bearing system whose anchors, material, routing and tether compatibility must be designed for that purpose. It should minimise excessive stretch, trip hazards and the possibility of a person being suspended outside the guardrails, and it requires inspection for wear, ultraviolet damage and corrosion.