Just by accident I found this old German Navy Sailor knife called “Bordmesser” in the drawer of my father in law. A well used vintage knife from 1964 by Hugo Köller Solingen. He told me he got the knife from a fisherman who killed the fish with the Marlinspike / Marlspieker. (the usual purpose is to fix ropes or to open knots).
German Navy knife – Bordmesser BW