A method for triple tensioning of a mooring system with anchors on a seabed

A method for tensioning of a mooring system with anchors on a seabed, in where a vessel (6) comprises one or more moonpools (1) having a through running vertical channel with an upper moonpool opening in proximity to a deck of the vessel (6), and a bottom moonpool opening open to surrounding sea, said moonpool (1) comprises one or more chain stoppers (5), and the vessel (6) further comprising one or more tensioning winches (2), one or more chain handling winches (3), and one or more abandon and recovery winches (4),

• wherein the method comprises the steps:
• a) deploying a first anchor line with a proof loading chain (15) connected to a first anchor (10) on a first location on the seabed (14), said anchor (10) is deployed from the stern of the vessel (6) and embedded in the seabed (14) using bollard pull from the vessel (6),
• b) deploying a second anchor line with a proof loading chain (15) connected to a second anchor (10) on a second location and deploying a third anchor line with a proof loading chain (15) connected to a third anchor (10) on a third location, by repeating step a),
• c) moving the vessel (6) to pick up the second anchor line and the third anchor line through the moonpool (1) of the vessel (6), while the first anchor line is connected to the tensioning winch (2) and runs over the stern of the vessel,
• d) on the location for picking up the second anchor line;
• deploying a pick-up wire with a connectable hook (11) through the moonpool (1) from the abandon and recovery winch (4),
• connecting the pick-up wire to the proof loading chain (15) from the anchor (10),
• recovering the pick-up wire with the proof loading chain (15) through the moonpool (1) and engaging the chain stopper (5) to take over the load from the proof loading chain (15), and
• connecting the proof loading chain (15) with a chain from the chain handling winch (3),
• e) moving the vessel (6) to the location for picking up the third anchor line, and repeating step d) for the third anchor line,
• f) tensioning the first anchor line to tension all three proof loading chains of the three anchor lines,
• g) performing a proof loading test of the three-legged mooring system, and
• h) using the chain handling winch (3) to adjust both in and out on the proof loading chains (15), in case of uneven embedding/tension on the anchors (10).