A novel shank is provided for an anchor which greatly improves the retention capacity of the anchor. The shank has a tip joined by an intermediate portion to a body portion. These three elements when at rest are in alignment along the longitudinal axis of the shank. The shank is inflexible in a first plane and is flexible in a second plane which is oriented at 90.degree. to the first plane to an extent such that the tip can be moved in the second plane into a position wherein it is substantially normal to the longitudinal axis without permanent deformation of the shank.

An anchor is used for anchoring a hull or a floating body on the water. When the anchor of the present invention is made to land on the bottom of the water, left and right bills and a lower auxiliary bill encroach the bottom of the water and thus to make anchoring positive, and as a shank, bills and a bill stopping frame are relatively thin, said anchor is lighter than the conventional anchors. Consequently the resistance of the sediment in the bottom of the water is minimized with respect to the encroachment, and therefore the work and labor during casting and weighing said anchor can be relieved.

Anchor structures including a flexible shank having improved fluke, crown and shank attachment and crownless designs which enhance bottom penetration and burying capability.

An improved anchor having a shank and, pivotally connected thereto, a head consisting of a generally flat, arcuate body, a pair of flukes attached to the body and extending laterally from a plane of the shank and body, and a bottom penetrating nose portion, has the further features of the body and shank having a narrowed lead edge and the material of the shank and body being disposed in rectangular cross-sections having substantial ratios of height to thickness. The shank and body of the anchor thereby have a thin lead edge profile to facilitate passage of the anchor through a bottom surface to burrow into the bottom, and the shank has broad side surfaces to resist anchor dislodgement under side forces.

A convertible anchor capable of being converted between a first position usable on sandy bottom floors and a second position usable on debris laden bottom floors, such as reefs. The convertible anchor may include an elongated shank and one or more flukes rotatably coupled to the elongated shank. The convertible anchor may also include an engagement limiting device placing the convertible anchor in a first position in which the fluke is prevented from rotating relative to the elongated shank. The convertible anchor may also include a catch device so that the convertible anchor can grab a debris laden bottom when the convertible anchor is in the second position.