Anchor shackles come in a wide variety of types. Classified by shape, they include straight and round shackles; by application, they are distinguished as anchor chain shackles and sail/line shackles; and by the type of pin, they can be divided into threaded pin shackles and plain straight pin shackles, with the latter using cotter pins for fixation. Sailing/line shackles are further divided into those specifically for fiber ropes and those specifically for steel cables. Shackles used for fiber ropes have a larger inner diameter ring; round shackles are commonly used for fiber ropes.
Shackles commonly used on ships are for connecting anchors and anchor chains. Some shackles can be used to connect both anchors and anchor chains, and a few ships also use them to connect anchor chains. These shackles are characterized by their pins and ferrules not protruding outside the ring, allowing for smoother passage through various anchoring devices. Shackles used on large ships to connect anchors and anchor chains, as well as for mooring buoys, are mostly specialized shackles.
