A hybrid dynamically installed anchor with a folding shank, comprising a folding-shank plate anchor, a ballast shaft, an extension rod, a plurality of rear fins, and a recovery hole from a front end to a tail end of the hybrid dynamically installed anchor;
- said folding-shank plate anchor is used to provide holding capacity, said ballast shaft is used to force the folding-shank plate anchor to achieve an enough penetration depth in a seabed, and said extension rod and rear fins are used to improve a directional stability of the hybrid dynamically installed anchor during free fall in a seawater;
- said folding-shank plate anchor further comprises a fluke, a shank, a support, and a connecting bar;
- said fluke is a symmetric triangular-shaped or peltate-shaped plate, with a thickness decreasing from a central line to an edge of the fluke;
- and the edge of the fluke is round-grinded to reduce a drag force on the hybrid dynamically installed anchor during free fall in the seawater and a soil resistance on the hybrid dynamically installed anchor during dynamically penetration in the seabed;
- said support is fixed on a central line of the fluke;
- said shank has a first end and a second ends, the first end of the shank is hinged to the support through a pivot shaft, and the second end of the shank is free;
- said second end of the shank has a padeye to connect a mooring line;
- said shank is further fixed to the support by a shear pin (a), the shank is folded and is parallel to the central line of the fluke when the shear pin (a) is intact, and the shank rotates around the pivot shaft when the shear pin (a) is broken under a pullout load at the padeye;
- a one-way bearing is installed between the shank and the pivot shaft, so that the second end of the shank only rotates to an orientation outwards from the fluke;
- said connecting bar is fixed at a tail of the fluke, and a central line of the connecting bar is collinear with the central line of the fluke;
- said ballast shaft further comprises a semi-ellipsoidal tip, a cylindrical mid-shaft, and a circular-truncated-cone shaped tail, wherein the semi-ellipsoidal tip, the cylindrical mid-shaft, and the circular-truncated-cone shaped tail are connected through threads;
- said cylindrical mid-shaft of the ballast shaft has varied lengths to adjust a total weight of the hybrid dynamically installed anchor, so that the hybrid dynamically installed anchor achieves an enough penetration depth in the seabed;
- said semi-ellipsoidal tip of the ballast shaft has an axial slot to accommodate the connecting bar of the folding-shank plate anchor;
- said semi-ellipsoidal tip of the ballast shaft further has a horizontal hole (a), and the connecting bar of the folding-shank plate anchor further has a horizontal hole (b), and a shear pin (b) is sealed in the horizontal hole (a) and the horizontal hole (b) to connect the ballast shaft and the folding-shank plate anchor;
- said extension rod has a cylindrical profile, and the extension rod enlarges a distance from the rear fins to a tip of the folding-shank plate anchor to keep the directional stability of the hybrid dynamically installed anchor during free fall in the seawater;
- said extension rod further has first and second ends;
- the first end of the extension rod is connected to a tail of the ballast shaft, and
- the second end of the extension rod has a recovery hole to connect a retrieval line;
- said rear fins further comprise a plurality of plate rear fins and an arched rear fin, and are connected towards a rear of the extension rod and below the recovery hole to keep the directional stability of the hybrid dynamically installed anchor during free fall in the seawater;
- the extension rod and rear fins are fabricated from light-weight materials, and the extension rod is further fabricated with hollow structure to lower a gravity center of the hybrid dynamically installed anchor;
- a central line of the extension rod, a central line of the ballast shaft, and a central line of the folding-shank plate anchor are collinear;
- the gravity center of the hybrid dynamically installed anchor is lower than a hydrodynamic center of the hybrid dynamically installed anchor to keep directional stability during free fall in the seawater.