Disconnectable spread mooring and riser tower system and method

A disconnectable spread mooring assembly for a vessel floating at a water surface, the vessel having a bow and a stern, the disconnectable spread mooring assembly comprising:

• a forward chain table assembly releasably connected to the vessel at the bow;
• an aft chain table assembly releasably connected to the vessel at the stern, wherein each of the forward and aft chain table assemblies comprises one or more buoyancy compartments and the forward and aft chain table assemblies are arranged and designed to float at or near the water surface when disconnected from the vessel;
• a plurality of bow mooring legs having first ends attached to the forward chain table assembly and having second ends capable of being anchored at spaced locations on a seafloor;
• a plurality of stern mooring legs having first ends attached to the aft chain table assembly and having second ends capable of being anchored at spaced locations on the seafloor;
• a first connector assembly connecting the forward chain table assembly to the vessel at the bow;
• a second connector assembly connecting the aft chain table assembly to the vessel at the stern, wherein the first and second connector assemblies are arranged and designed to unlock and release the forward and aft chain table assemblies from the vessel;
• a first tie-back hawser or chain, or combination of hawser and chain, connected to the forward chain table assembly;
• a second tie-back hawser or chain, or combination of hawser and chain, connected to the aft chain table assembly;
• and
• one or more fixed jacket structures fixed to the seafloor,
• wherein the first and second tie-back hawsers or chains, or combinations of hawser and chain, are arranged and designed to connect to the one or more fixed jacket structures when the forward and aft chain table assemblies float at or near the water surface.

A disconnectable spread mooring and riser tower system for a vessel floating at a water surface, the vessel having a bow and a stern, the disconnectable spread mooring and riser tower system comprising:

• a forward chain table assembly releasably connected to the vessel at the bow;
• an aft chain table assembly releasably connected to the vessel at the stern;
• a plurality of bow mooring legs having first ends attached to the forward chain table assembly and having second ends capable of being anchored at spaced locations on a seafloor;
• a plurality of stern mooring legs having first ends attached to the aft chain table assembly and having second ends capable of being anchored at spaced locations on the seafloor;
• a first connector assembly connecting the forward chain table assembly to the vessel at the bow;
• a second connector assembly connecting the aft chain table assembly to the vessel at the stern, wherein the first and second connector assemblies are arranged and designed to unlock and release the forward and aft chain table assemblies from the vessel;
• a first pull-in assembly on the vessel at the bow;
• a second pull-in assembly on the vessel at the stern,
• wherein the first pull-in assembly is arranged and designed to lower the forward chain table assembly and the first ends of the plurality of bow mooring legs from the vessel upon unlocking the first connector assembly,
• the second pull-in assembly is arranged and designed to lower the aft chain table assembly and the first ends of the plurality of stern mooring legs from the vessel upon unlocking the second connector assembly;
• a riser tower system fixed to the seafloor and located near the moored vessel;
• and
• one or more flexible jumper hoses extending between the riser tower system and the vessel to transfer one or more of:
• fluids, air, power and control signals.

A method for disconnecting a floating vessel having a bow and a stern from a spread mooring system at a moored location, the spread mooring system including a plurality of bow mooring legs anchored at spaced locations on a seafloor and connected to a forward chain table assembly connected to the vessel at the bow, and a plurality of stern mooring legs anchored at spaced locations on the seafloor and connected to an aft chain table assembly connected to the vessel at the stern, the method comprising the steps of:

• unlocking a first connector assembly securing the forward chain table assembly to the vessel;
• releasing the forward chain table assembly from the first connector assembly and lowering the forward chain table assembly with a first pull-in assembly into the water;
• unlocking a second connector assembly securing the aft chain table assembly to the vessel;
• releasing the aft chain table assembly from the second connector assembly and lowering the aft chain table assembly with a second pull-in assembly into the water;
• securing the positioning of the forward and aft chain table assemblies in the water;
• and
• moving the vessel to another location with the forward and aft chain table assemblies and pluralities of bow and stern mooring legs remaining at the moored location.