Marine propeller design, tests and manufacture

Hofmann, Thomas (1991) Marine propeller design, tests and manufacture. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (24MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

This thesis presents three aspects of marine propeller technology. 1) the theoretical design of small propellers; 2) some aspects of manufacturing, in particular, propeller casting; and 3) tests on full scale vessels. Although this work was done in the context of small fishing vessels, most of it is applicable to ships' propellers in general. -- Two lifting line theory propeller design programs were written and tested. Their usefulness was demonstrated by using test cases which involved real vessels and experimental test results. Through development of lifting surface corrections, results can be produced, from the lifting line theory which closely approximate experimental test data; also, propellers for specific vessels have been designed using the new programs. The lifting line methods for propeller design, as used here, are useful methods for designing propellers for small vessels for which few propulsive or resistive data are available and for preliminary design of other subcavitating propellers. -- A 1/5 scale model of the vessel UMV SUGAR was constructed to do a set of model tests: resistance tests; open water propeller and self propulsion tests; and hot film anemometer wake measurements. Although the model was designed and constructed by the author, the tank testing was done by a visiting post-doctoral fellow, Dr. Shukai Wu. The testing program was done to determine the propulsion and resistance data required for lifting line propeller design and to compare model and full scale results. A graph of the Taylor wake fraction and thrust deduction fraction as measured from the model are given in the appendix. Complete test results are given in the reference. -- Sea trials were performed to determine vessel propulsive performance of the UM V SUGAR and the MV BECKY A. by using a purpose designed and instrumented propeller stub shaft. Results from both full scale trials were analysed. These tests confirm previous claims of very poor propulsive efficiency for these vessels. -- A method for commercially producing a propeller casting was developed. This method did not require the use of a solid pattern to produce the mould. A strickle gear was designed and built to construct propeller moulds for propellers up to 24 inches in diameter. An expert system was developed to ensure that casting quality could be maintained through information access on mould design. The system was tested by producing a prototype propeller mould and casting for a model propeller.

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