VESSEL MOORING SYSTEM

摘要

A vessel with a mooring recess on the bottom of the hull moors to a submerged buoyant mooring element anchored to the ocean bottom by hoisting the mooring element from a stowed position at a depth of net neutral buoyancy of the mooring element and its anchoring system into contact with the mooring recess. The mooring operation is completed safely, quickly, and positively by rapidly withdrawing seawater into the hull through an opening in the mooring recess so as to reduce the hydrostatic pressure acting on the top of the mooring element as the element comes into contact with the hull of the vessel. The pressure reduction is sufficient to shift the mooring element and its anchoring system from a net negative to a net positive buoyancy condition at the keel depth of the vessel. The seawater may be withdrawn by a high capacity pump that is either specifically installed for this purpose or is part of a bow thruster system of a type commonly found on large vessels. Alternative, or additional, seawater suction apparatus includes an evacuated hermetic chamber having a valve opening into the mooring recess. The mooring recess may be coaxial with a vertical well in the hull, in which case water in the well may be drained into an empty hold through a valve opening into the well near the bottom of the hull. The mooring element has an upper part that makes sealing contact with the hull of the vessel and a lower part that is connected to the anchor lines. At least one bearing mounted between the parts permit the upper part to rotate relative to the lower part, so that the vessel may weathervane in response to wind, wave, and current forces.