MODIFICATION OF PROPELLERS FOR SATISFACTORY USE THROUGHOUT A SHIP'S LIFETIME
When designing a ship's propeller, simultaneous consideration has to be given to the characteristics of the hull, such as service speed, resistance, wake, operating draughts, etc., and the engine data, especially the maximum continuous power, rated rpm, shafting losses, etc. During the service life of a ship its hull condition deteriorates gradually, giving rise to a continuing increase in resistance. At the same time, the power developed by the engine, under given conditions of rpm and exhaust temperatures, may decrease with age. These two circumstances bring about a gradual deterioration in the efficiency of a fixed-blade propeller, and can result in engine overloading that is highly damaging. In this paper the service conditions which can lead to deterioration of the propeller are analysed. Methods that may be used to modify the propeller in situ to adapt it to changing conditions of the hull/engine system are considered. A comparison is made between the effects on performance of reducing the propeller diameter and cutting away the damaged trailing edges of the blades, a technique recently introduced by Kawasaki Heavy Industries. An Appendix presents the results of tests with the latter method in a cavitation tunnel.
- Presented at the 13th Technical Meeting on Marine Engineering, in Asturias, June 2-4, 1976.
Asociacion de Ingenieros Navales38 General Goded
- O'Dogherty, P
- Gomez, A G
- Publication Date: 1976
- Features: References;
- Pagination: 47 p.
- TRT Terms: Engine operation; Hulls; Propellers; Roughness; Vehicle design
- Old TRIS Terms: Engine overloading; Hull roughness; Propeller design; Propeller efficiency; Propeller modification
- Subject Areas: Design; Marine Transportation; Vehicles and Equipment;
- Accession Number: 00159974
- Record Type: Publication
- Source Agency: British Ship Research Association
- Report/Paper Numbers: Proceeding
- Files: TRIS
- Created Date: Sep 20 1977 12:00AM