The thrust fluctuation of a propeller is an important part of the ship's vibration exciting force. The so-called air spring thrust block, vibration isolation equipment using air springs combined with height control valves was invented to isolate the thrust fluctuation. An air spring thrust block, the natural frequency of which was designed to be one- sixth of the frequency of thrust fluctuation at a normal operating speed, was installed aboard a ship 30 m long to measure the transmissibility of the thrust fluctuation at sea. As a result of the measurement, it was proven that while the transmissibility of the thrust itself was 100%, the transmissibility of thrust fluctuation was under 4%, where measured values and theoretically calculated values agreed well with each other. Furthermore, the air spring thrust block for ships driven by the geared diesel engine was so designed as to ensure its applicability. To avoid uncomfortable vibration, many kinds of air springs have already been applied to railway coaches and other vehicles with successful results; thus it can be expected that the air spring thrust block will also result in a more comfortable ride on ships.

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  • Corporate Authors:

    Ishikawajima-Harima Heavy Industries Co., Ltd.

    2-16, Toyosu 3 Chome, Koto-Ku
    Tokyo 135,   Japan 
  • Authors:
    • Kunieda, M
    • Mano, M
    • Fujii, K
    • Okada, Y
  • Publication Date: 1977-1

Media Info

  • Features: Appendices; Figures; References;
  • Pagination: p. 10-20
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00151981
  • Record Type: Publication
  • Source Agency: Ishikawajima-Harima Heavy Industries Co., Ltd.
  • Files: TRIS
  • Created Date: Apr 13 1977 12:00AM