A shackle is a u-shaped, load-bearing connecting device designed to be used with a removable pin. Shackles can be used in a number of rigging and load securement applications to connect different types of lifting slings, chain, or rope to an object.
The terms anchor shackles and bow shackles are both used interchangeably and refer to a type of shackle with a larger, round “O” shaped bow. A larger bow shape allows these types of shackles to be side loaded or used in multiple sling-leg connections. Anchor shackles can be used for side pulling when you factor in the reduction to the WLL based on the angle deviation from in-line (0°).
Chain shackles, also referred to as Dee shackles, have a D-shaped bow that is narrower than anchor shackles. Because these shackles are designed and rated for in-line tension, they should not be side loaded, as side loading can twist or bend the bow of the shackle. When using a chain shackle, the center line of the load should always coincide with the center line of the shackle when in use.