sling-stay

from The Century Dictionary.

• noun One of the rods or braces in a steam-boiler by which the girder or crown-bar stays are tied to a part of the shell which resists strain in an opposite direction. In a locomotive-boiler, for example, the crown-sheet of which is stiffened from collapse by crown-bars, the bars are tied to the sides of the dome overhead by sling-stays, which hold the dome down and resist flexure of the bars.