Gravity installed anchor

Abstract

A gravity installed anchor including a metal plate provided with one or more connection points for extending an anchor line from a front face of the plate. The gravity installed anchor preferably includes an elongated shank connected to the plate and arranged for being directed along the plate during the gravity installation process, the elongated shank provided with a nose portion with a nose. The plate may be rotated to an angle relative to the shank after being gravity installed in the seafloor.

1 . A gravity installed anchor including
 a main anchor plate with one or more connection points for extending an anchor line from a front face of said anchor plate and with a rear face opposite to said front face,   an elongated shank connected at hinge to said anchor plate and arranged for extending near vertically and parallel with said anchor plate during gravity installation,   wherein   said hinge arranged for allowing rotating said anchor plate away from a vertical plane and said shank after gravity installation,   said shank extending downwards from said hinge.   
     
     
         2 . The gravity installed anchor of  claim 1 , said hinge arranged at a top stern portion of said shank. 
     
     
         3 . The gravity installed anchor of  claim 1 , said hinge having a generally horizontal pivot axis. 
     
     
         4 . The gravity installed anchor of  claim 1 , a horizontal rotation axle forming said horizontal pivot axis. 
     
     
         5 . The gravity installed anchor of  claim 1 , further comprising that said hinge is arranged near a centre of said anchor plate. 
     
     
         6 . The gravity installed anchor of  claim 1 , further comprising that said hinge is arranged near a central part of an upper portion of said anchor plate. 
     
     
         7 . The gravity installed anchor of  claim 1 , said plate being tapered in its lower portion to a general V-shape. 
     
     
         8 . The gravity installed anchor of  claim 1 , the number of said connection points being at least two, each said connection points for being connected to corresponding respective bridle lines of said mooring line. 
     
     
         9 . The gravity installed anchor of  claim 1 , provided with a recess for receiving said shank in said rear face of said anchor plate. 
     
     
         10 . The gravity anchor of  claim 9 , said recess corresponding to a ridge on said front face. 
     
     
         11 . The gravity installed anchor of  claim 1 , said anchor plate provided with one or more guides such as a guide plate extending at right angles to said hinge's axis. 
     
     
         12 . The gravity installed anchor of  claim 11 , said guide plate parallel to a slot along part of said shank, said slot for receiving said guide plate or plates. 
     
     
         13 . The gravity installed anchor of  claim 1 , at least two of said connection points arranged on either sides of a vertical central line on said anchor plate. 
     
     
         14 . The gravity installed anchor of  claim 1 , the number of said connection points being three. 
     
     
         15 . The gravity installed anchor of  claim 14 , said connection points arranged in a triangular pattern about near a centre of said anchor plate, one of said connection points arranged near said vertical central line on said anchor plate for being connected to a bridle line of said mooring line. 
     
     
         16 . The gravity installed anchor of  claim 1 , provided with an installation connection point for an installation line near a top end of said anchor plate. 
     
     
         17 . The anchor of  claim 1 , said plate being massive. 
     
     
         18 . The anchor of  claim 1 , said plate being laminated from a number of thinner steel plates. 
     
     
         19 . A method for anchoring using a gravity installed anchor wherein
 providing a massive metal plate with a downwards extending stem hinged to said plate and an installation connection point at a top end;   connecting an anchor line to one or more connection points at a front face of said plate;   attaching an installation line to said installation connection point;   using said installation line, lowering said plate to a desired elevation (h) above a predetermined position (x, y) on the seafloor;   releasing said plate from said elevation (h);   letting said plate drop and penetrate said seafloor due to gravity;   tensioning said anchor line along a predetermined line of tension;   connecting an opposite end of said anchor line to a vessel to be anchored.   
     
     
         20 . The method of  claim 19 , tensioning said anchor line so as for tilting said plate towards an orthogonal position relative to said anchor line. 
     
     
         21 . The method of  claim 19 , wherein after the step of lowering the plate to a desired elevation (h) above the seafloor,
 directing said plate in an azimuthal direction transverse to said predetermined line of tension of said anchor line.   
     
     
         22 . The method of  claim 19 , verifying the direction of said plate after letting said plate penetrate said sediments. 
     
     
         23 . A method for installing a gravity installed anchor according to  claim 19 ,
 including   providing one or more gravity installed anchors;   providing a penetrometer of reduced dimensions and with similar design and penetration properties as said one or more gravity installed anchor;   lowering said penetrometer to a controlled elevation above the seafloor near a selected anchor installation location;   releasing said penetrometer to penetrate said seafloor;   measuring at least a penetration depth of said penetrometer;   configuring one of said gravity installed anchor according to the measurement above by one or more of the below actions:   determining the release drop elevation for the gravity installed anchor;   selecting an anchor between available different gravity installed anchors;   designing a gravity installed anchor based on said measurement;   ballasting a gravity installed anchor to higher or lower weight based on said measurement.   
     
     
         24 . The method according to  claim 23 , using a sediment sampler in said penetrometer for providing sediment samples.