stay

A stay is a rope, wire rope, or metal rod that runs from the mast or other spar down to the hull or deck of a vessel, where it is secured to resist forces trying to bend or topple the mast. The most common stays are the forestay (running forward from the mast to the bow) and the backstay (running aft to the stern). Stays work in tension, pulling the mast into alignment; they are structural members, not merely rigging.

Standing stays differ from running rigging in that they are permanent or semi-permanent fixtures. A wooden sailing ship might have two or three sets of stays, each made of rope and each replaceable under normal maintenance. Steel and modern vessels use wire rope, usually galvanized or stainless steel, which carries far greater load and deteriorates more slowly. The diameter increases with the span of the mast and the forces expected: a harbor tugboat's mast might use 10 mm wire, while a fishing vessel's might use 16 mm or larger.

The stay is attached to the mast at a point called the band or collar, set well below the truck (the top of the mast). At the lower end, it is secured via a turnbuckle (a threaded device that allows tensioning), a chain plate bolted to the hull, or a dedicated deck eye. In sailing vessels, the forestay also serves as the support for the foresail or jib; in such cases it must be rigid enough to hold the sail's shape under wind load.

Failure and inspection

Stays fail when corrosion weakens wire rope, when the connection points fracture due to metal fatigue, or when improper tensioning causes the mast to whip. A slack stay allows the mast to move laterally; an over-tensioned stay can cause hogging (sagging of the hull's ends) or cracking of the deck where it is fastened. Routine inspection involves checking for rust, kinks, broken strands, and movement at each attachment point. Replacement is scheduled work, typically done during annual haul-out.

The term stay derives from its function: it stays, or holds, the mast in place. The word appears in maritime records from the 17th century and has remained unchanged. Related terms include guy (a stay used to steady a cargo boom), shroud (lateral support for the mast), and lanyard (a short rope or line used for securing loose items). In shipyard vocabulary, a mast without proper stays is said to be unguyed or unsupported, and no vessel is permitted to leave dock in that condition.