A shackle (also called gyve) is a U-shaped piece of metal secured with a pin or bolt across the opening, or a hinged metal loop secured with a quick-release locking pin mechanism. They are used as a connecting link in all manner of rigging systems, from boats and ships to industrial crane rigging. A carabiner is a variety of shackle used in mountaineering.
Alternatively, some threaded shackles are provided with a hole through the threaded end of the pin beyond where it emerges from the threaded hole. A cotter pin or a couple of loops of mousing wire through this hole serves the same purpose and secures the shackle in a closed position. Nylon Zip-Ties are also commonly used in applications such as theater where the shackle must be secured, but easy removal of the mousing is required.
In this context, 'mouse' and 'mousing' are often pronounced with a harder 's', like mouze and mouzing.
Note that when mousing, the introduction of any other metal into permanent, direct contact with a safety-critical shackle may seriously reduce its (or the other metal's) useful life, especially under water and more especially under sea water. Frequent wetting or immersion, followed by exposure to the air again, is absolutely the worst combination. This is particularly relevant to shackles that form part of permanent moorings and anchor cables. For this reason, specially alloyed mousing wire is available and should be exclusively used for this purpose at all times. The use of galvanised or stainless steel cotter pins can have similar drawbacks.
As the name implies, a snap shackle is a fast action fastener which can be implemented single handed. It uses a spring activated locking mechanism to close a hinged shackle, and can be unfastened under load. This is a potential safety hazard, but can also be extremely useful at times. The snap shackle is not as secure as any other form of shackle, but can come in handy for temporary uses or in situations which must be moved or replaced often, such as a sailor's harness tether or to attach spinnaker sheets. Note: When this type of shackle is used to release a significant load, it will work rather poorly (hard to release) and is likely to have the pin assembly or the split ring fail.
Patent Application Titled "Shackle or Clevis Mount Fitting for Steel Cable and Synthetic Rope End Loops" under Review
Nov 29, 2012; By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington,...