A D-shackle or simply a chain shackle is shaped like a loop of chain. D-shackles are used as connecting links in boats, ships, crane rigging and … .
A screw pin chain shackle is a U-shaped shackle secured with a screw pin. It connects lifting components. The loop in chain shackles is narrower than the one in anchor shackles. The narrow loop is designed to support a heavier load than a similar size anchor shackle.