Acoustical mooring release system

A semi-submersible drilling rig or the like having a plurality of chain lockers, a plurality of anchor windlass assemblies and a plurality of fairlead assemblies, a plurality of lengths of chain each having a multiplicity of interconnected links configured to move from a chain locker in cooperative relation through an associated anchor windlass assembly and an associated fairlead assembly, an anchor for each length of chain, and a connector connecting each anchor to the end of the associated length of chain outboard of the associated fairlead assembly so as to engage with the water bottom. The invention further comprises providing in each length of chain at least one link normally disposed within the chain locker inboard of the associated anchor windlass and fairlead assemblies, each of which includes a plurality of removably interconnected parts operable when interconnected to interengage with the adjacent links of the associated length of chain. Each one link has removable fasteners normally retaining its parts in interconnected relation in interengagement with the adjacent links and is adapted to receive within its confines an acoustical receiver and bolt assembly. Each assembly retains the link parts together and is operable in response to a predetermined transmitted acoustical signal after the associated one link has been moved to an operative position outboard of the associated fairlead assembly, to detonate thereby separating the link parts.