Anchor shackles are used to connect anchor chains and sledgehammers. When using them, the horizontal bolt should face upwards (towards the buoy). The horizontal bolt's round shape prevents it from rotating in the bolt hole and increases its strength. To use, first remove the horizontal bolt from the shackle, then slip the "U" shaped buckle onto the anchor chain ring to be connected, and then connect the horizontal bolt to the upper anchor chain ring.
To prevent the horizontal bolt from coming loose, there is a beveled hole at each end where it mates with the "U" shaped buckle, for inserting a brake pin. To prevent the pin from coming loose, lead should be driven into the hole to seal it. Calcium-based grease should be applied before inserting the pin into the hole for rust prevention.
