Rigging Hardware and Attachments
Core concepts
Hardware includes shackles, hooks, eye bolts, turnbuckles, links, and swivels. Each has a rated capacity and a correct orientation. Shackle pins must be fully seated and the load should bear on the bow, not the pin, where the design requires it. Hooks need a functioning latch and must not be tip-loaded. Eye bolts are rated for axial pull only unless explicitly designed for angular loading. Know that hardware capacity is the weakest link in the assembly and that mixing components from different ratings lowers the system limit.
Traps to watch
Common distractors test side-loading of eye bolts, using a shackle with the load on the pin, or substituting a hardware-store bolt for a rated pin. Another trap is hook latches-latches are for keeping slack slings in place, not for carrying load. Questions may show mismatched hardware sizes or ask whether a bent shackle can be straightened; the answer is always to remove it from service. Watch for capacity questions where the assembly rating equals the lowest-rated component.
Worked example
An assembly uses a 7-ton shackle, a 5-ton hook, and a 6-ton master link. The system capacity is 5 tons-the weakest component. Rule of thumb: always rate the system by its lowest-rated part, and verify that pins, bolts, and nuts are the original rated hardware, fully engaged.