STUDY OF CONTRA-ROTATING PROPELLER ARRANGEMENTS FOR MERCHANT SHIPS

The technical and economical feasibility of contra-rotating propellers and corresponding machinery arrangement has been evaluated. The aim of the study has been to investigate the performance characteristics for the propulsors and to develop operational propellers, shafting and gearing for steam turbine and medium speed diesel plants. Both 150 000 tdw tanker and a 12 000 tdw fast going container ship have been considered. The gain in propulsive efficiency is found to be about 6 percent over a conventional single screw for the tanker, both screws having optimum diameter at a given speed. For the container ship a gain of 12 percent was obtained, both screws having the same diameter. Thus the hydrodynamic studies have verified expected gains in performance and given confidence to the operability of the contra-rotating propellers. Detailed and operational designs for gearing and shafting have been developed. However, although being regarded a technical feasible alternative the contra-rotating propeller arrangement is at present only commercially justified as a twin screw alternative provided that adequate guarantees can be ensured.

• Supplemental Notes:
  • Prepared by The Swedish Working Group of 1965 for studies and development of contra-rotating propeller arrangements
• Corporate Authors:

  Stal-Laval Turbin AB

  612 20 Finnspong,   Sweden 
• Authors:
  • Larson, Gunnar A
• Publication Date: 1970-4-1

Media Info

• Features: Figures; Tables;
• Pagination: 131 p.

Subject/Index Terms

• TRT Terms: Contrarotating propellers; Diesel engines; Engine efficiency; Propellers; Propulsion; Steam power plants
• Old TRIS Terms: Diesel propulsion; Propulsive efficiency; Twin screws
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00005447
• Record Type: Publication
• Files: TRIS
• Created Date: Oct 30 1973 12:00AM