Underwater chain stopper and fairlead apparatus for anchoring offshore structures

A fairlead latch mechanism for securing an anchor line comprising a chain with links and a section of cable between an offshore structure and an anchor, the fairlead latch mechanism comprises:

• a fairlead housing having a pivoting mounting bracket attached to a surface of the offshore structure, and said fairlead housing including a sheave;
• a latch housing;
• a pivoting mounting member for coupling said latch housing to said fairlead housing;
• said latch housing including a chain stopper, said chain stopper including a flapper and a frame member, said flapper having a slot opening at one end for allowing passage of chain links in the anchor line, and said flapper including a chain link seat at said end for blocking any one of the chain links and preventing passage of the anchor line;
• wherein said flapper is responsive to gravity and moves under the force of gravity to a position for preventing passage of the chain links in the anchor line;
• wherein said frame member includes a recess on the surface contacting said flapper;
• said flapper including an extension on the surface contacting said frame member;
• and,
• said extension having a shape substantially the same as said recess so that said extension is seatable in said recess to reinforce said flapper.

An apparatus for mooring an offshore vessel with one or more anchors coupled to respective anchor chains, said offshore vessel having a hull, said apparatus comprising:

• means for guiding the anchor chain from the surface of the offshore vessel to the anchor;
• means for mounting said guiding means to the hull, said means for mounting providing a pivotable connection between the hull and said means for guiding;
• means for stopping the anchor chain, said means for stopping being coupled to said means for guiding though a second pivotable connection;
• and
• said means for stopping moving to a closed position under the force of gravity for stopping the anchor chain.

An apparatus for anchoring an offshore structure, said offshore structure having an underwater surface, said anchoring apparatus comprising:

• a frame member, said frame member being coupled to the underwater surface;
• a mounting member, said mounting member being connected to said frame member;
• a fairlead;
• a chain stopper wherein said chain stopper comprises a flapper, said flapper being movable between an open position and a closed position, said flapper having a first slot for allowing passage of chain links in an anchor chain, and a chain link seat for preventing passage of chain links in the anchor chain in said closed position;
• said mounting member including a shaft for connecting said fairlead and a pivoting coupler for coupling said chain stopper;
• wherein said flapper is responsive to gravity and moves to said closed position under the force of gravity;
• a safety cable mechanism comprising a safety cable and a coupler device;
• said safety cable having one end connected to said mounting member and another end connected to said coupler device;
• and
• said coupler device being fastened to at least one chain link in said anchor chain.