A BASIC STUDY ON THE STABILITY OF ANCHORS

The present paper deals with fundamental investigations on the maximum holding power and the stability of stockless anchors dragged in non-cohesive media. The characteristics of forces acting on each structural element of anchor, such as flukes, stabilizing fins and shanks were studied experimentally. In order to analyze behaviors of an anchor in the seabed, the results obtained are given in empirical formulas. The maximum holding power of a marine anchor depends upon its configuration in the seabed. Considering force resultants and moments acting on all the structural elements, the equilibrium equations for an anchor are formulated, and the configuration of a dragged anchor and its maximum holding power can be determined by solving these equations. If its equilibrium configuration cannot be determined under the surface of the seabed, the dragged anchor will be embeded deeply in the bed or turn over as soon as flukes come out of the bed. This instability will be called lifting-up. Instability phenomena caused by turning around the shank are analyzed by considering resulting moments acting on the anchor in a disturbed condition form the equilibrium configuration. As the results, stability conditions for lifting-up and turning are proposed for the anchor dragged in non-cohesive media. Although experiments were performed with dry- or flooded-loose sand in this paper, it must be emphasized that characteristics of an anchor depend slightly upon the seabed where it works.

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  • Corporate Authors:

    Society of Naval Architects of Japan

    15-16, Toranomon, 1-chome, Minato-ku
    Tokyo,   Japan 
  • Authors:
    • Ura, T
    • YAMAMOTO, Y
  • Publication Date: 1978

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Filing Info

  • Accession Number: 00194329
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Jun 13 1979 12:00AM