Wikipedia
Pelican hook
A pelican hook is a piece of nautical rigging hardware composed of a hinged link held closed by a circumferential link capable of being released under load. Small examples are held closed by hand while the retaining link is displaced while larger examples are hit with a hammer or sledge hammer to release. The asymmetric appearance of the two hinged pieces is similar in appearance to a pelican's beak. It is frequently used to secure ships' anchors and life raft canisters but has many other applications.
Usage examples of "pelican hook".
But the New Jersey's pelican hook was as big as the Caine's main guns.