THRUST DEDUCTION IN CONTRAROTATING PROPELLERS

A theoretical method is presented for calculating the steady propulsive interaction (thrust deduction) force in contrarotating propellers. Contrarotating propellers operating at off-design loading and spacing as well as the contribution of a rudder were investigated. The importance of the separate thrust deduction of the forward and aft propellers in analyzing the behavior of a CR propeller set was shown. Numerical results are given for a MARAD high-speed containership. Some principal findings for the subject ship are: good agreement between theory and experiment with regard to the thrust deduction of a centerline rudder, at equal thrust the forward and aft propellers produced 73 percent and 27 percent of the total thrust deduction, respectively, and the total thrust deduction is reduced by unbalancing the propelling thrust with smaller thrust carried on the forward propeller.

• Corporate Authors:

  Naval Ship Research and Development Center

  Bethesda, MD  United States  20034
• Authors:
  • Beveridge, J L
• Publication Date: 1974-11

Media Info

• Pagination: 39 p.

Subject/Index Terms

• TRT Terms: Contrarotating propellers; Hulls; Mechanical loads; Propellers; Thrust
• Old TRIS Terms: Hull propeller interaction; Propeller loading; Thrust deduction
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00084865
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: NSRDC-4332
• Files: TRIS
• Created Date: May 19 1975 12:00AM