In the previous paper, very violent impact pressures on the stem were measured by experiments in high transient water waves. In this paper, the authors continued the experiments in order to take a somewhat closer look at some aspects of water impact to clarify the roles of certain mechanisms. Both the impact on the stem in full load condition and the impact on the bottom in the ballast condition were investigated. The ship model was equipped with a relative wave surface probe, so the relative velocity and angle between hull and wave surface were obtained. The following conclusions can be deduced from these studies: 1) Large impact pressures acting on the hull surface can be explained by the fundamental nature that is taken by theories and experiments of the drop of a two dimensional body or breaking waves on a vertical wall. 2) The maximum value of impact pressure is considered to be proportional to square of relative velocity, and the coefficient of impact pressure reaches 48 to 66 at the bottom, 17 at the stem. 3) When the relative angle between hull and wave surface at the moment of impact is large, the coefficient tends to be proportional to the square of the cotangent of the angle, as in Wagner's theory. As it decreases, it becomes proportional to the cotangent of the angle, as in Chuang's experiments. 4) When air is entrapped, large impact pressure occurs, but at the stem air is hardly entrapped because of its shape.

  • Availability:
  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 

    Society of Naval Architects of Japan

    15-16, Toranomon, 1-chome, Minato-ku
    Tokyo,   Japan 
  • Authors:
    • Takezawa, S
    • Hasegawa, S
  • Publication Date: 1974-6


  • Japanese

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00071550
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Nov 12 1974 12:00AM