Senhouse slip (GB)
Alternative term: Pelican hook (USAUnited States of America)
A hinged hook, fitted with a securing ring which can conveniently be released when under strain. It is used for holding chain for quick release.
In Great Britain, a senhouse slip fitted with a length of chain and a shackle is called a Blake stopper while a senhouse slip fitted with a bottle screw adjustement is called a screw stopper.
Please note that this is the term as it stands in the original IALAInternational Association of Marine Aids to Navigation and Lighthouse Authorities - AISM Dictionary edition (1970-1989)