STABILITY OF DRAGGED ANCHORS

The present paper deals with the investigation on the maximum holding power and the stability of stockless anchors dragged in non-cohesive media. In order to analyze behaviors of an anchor in sea beds, the characteristics of forces acting on each structural element of the anchor should be studied first. Forces and moments acting on the flukes, shank and stabilizer fins were measured, and then, empirical formulas for these components are proposed on the basis of these experimental results. The maximum holding power of a mooring anchor depends upon its configuration in the sea bed. Summation of forces and moments acting on all the structural elements leads to a set of equilibrium equations, which determines configurations of the anchor dragged in sand and its maximum holding power. Instability phenomena caused by lifting up and turning around the shank are analyzed on the basis of the above formulas considering three-dimensional effects of soil. As the results, stability conditions for the anchor are proposed, and it is shown, theoretically and experimentally, that a stable anchor without stabilizer fins can be realized. Although experiments were performed with dry-loose-sand in this paper, it must be emphasized that characteristics of an anchor depend slightly upon the sea bed where it works. Further investigations of the stability conditions along this line of thought must be effective for developing actual marine anchors of high holding power with good stability. /Author/

  • Corporate Authors:

    University of Tokyo

    Institute of Industrial Science, 7-3-1 Hongo, Bunkyo-ku
    Tokyo,   Japan 
  • Authors:
    • Ura, T
    • YAMAMOTO, Y
  • Publication Date: 1978-6

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00184591
  • Record Type: Publication
  • Source Agency: University of Tokyo
  • Report/Paper Numbers: Serial No. 174 Monograph
  • Files: TRIS
  • Created Date: Feb 3 1979 12:00AM