The increase in ship size in recent years has brought about an increase in propeller load and thus an inevitable decrease in propeller efficiency. Adoption of the ducted propeller is one of the ameliorating measures, and not a few large ships--sixteen mammoth tankers, two ore carriers, and one liquefied petroleum gas carrier--built by the authors' company were fitted with ducted propellers. Cavitation erosion, however, occurring atop the duct on the inside, has proved to be an unfavorable factor of the design. This paper reports on full-scale ship observations of the cavitation conducted on seven ships by means of TV cameras coordinated with stroboscopes, as well as the results of erosion model tests. Air injection into the incoming flow to the propeller--a technique tried recently on three new ships--seems to be a partially effective countermeasure.

  • Supplemental Notes:
    • Presented at the Annual Meeting of the Society of Naval Architects and Marine Engineers, New York, New York, November 13-15, 1975.
  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  United States  07306-2907
  • Authors:
    • OKAMOTO, H
    • Okada, K
    • SAITO, Y
    • Takahei, T
  • Publication Date: 1975-11

Media Info

  • Features: References;
  • Pagination: 16 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00127556
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Report/Paper Numbers: No. 7
  • Files: TRIS
  • Created Date: Nov 18 1975 12:00AM