Basic Ship Propulsion

J P Ghose • R P Gokarn

Book

“Basic Ship Propulsion” deals with the fundamentals of ship propulsion comprehensively and in some detail. The propulsion machinery inside the ship is however considered only very briefly. The first chapter describes the development of ships and ship machinery and then introduces various ship propulsion devices. Subsequent chapters deal with conventional screw propellers that are used in most ships today. Among the subjects covered are screw propeller geometry, the theory of propellers, propeller characteristics, hull-propeller interaction, propeller cavitation, strength of propellers and model experiments involving propellers. The design of propellers for ships as well as for tugs and trawlers is given in a separate chapter, which also discusses the application of propeller theory to design. Ship trials and service performance analysis are then described. Some miscellaneous topics including propeller unsteady forces, propeller induced vibration and noise, propulsion in a seaway, engine-propeller matching, and propeller manufacture and repair are discussed next. The last chapter of the book describes unconventional ship propulsion devices such as controllable pitch propellers, ducted propellers, contra-rotating propellers, azimuthing and podded propellers, cycloidal propellers and waterjet propulsion as well as energy saving and flow improvement devices such as various types of ducts and fins. There is a glossary of technical terms for those unfamiliar with ships. An important feature of the book is the large number of numerical examples to illustrate various points, over one hundred and fifty problems (with answers) and a set of review questions to facilitate self-study. The book also has nearly one hundred figures, appendices containing useful data and references for those who wish to pursue certain topics to a more advanced level.

J P Ghose • R P Gokarn Authors

J.P. Ghose obtained a degree in Naval Architecture in 1959 and worked briefly in the industry before joining the Department of Naval Architecture, Indian Institute of Technology, Kharagpur in 1962. He obtained his Ph.D. degree in 1970, became a professor in 1971 and was the Head of the Department (1972-74 and 1975-80). He was a member of several committees on shipping and shipbuilding set up by the Government of India. He spent a year at the University of Michigan, Ann Arbor with a UNESCO fellowship. He retired from IIT Kharagpur in 1995.

R.P. Gokarn obtained a degree in Naval Architecture in 1962 and joined the Indian Institute of Technology, Kharagpur shortly thereafter. He obtained his Ph.D. in 1971. Professor Gokarn was Head of the Department of Naval Architecture during 1980-1983, Dean of Postgraduate Studies and Research (1993-96) and Member, Board of Governors (2000-01), IIT Kharagpur. After his retirement from IIT Kharagpur in 2002, Professor Gokarn has been associated with the OERC Group, Mumbai.

Contents

Preface
Acknowledgements
Glossary
Nomenclature
Physical Constants


Chapter 1 GENERAL INTRODUCTION
1.1 Ships
1.2 Propulsion Machinery
1.3 Propulsion Devices

Chapter 2 SCREW PROPELLERS
2.1 Description
2.2 Propeller Geometry
2.3 Propeller Blade Sections
2.4 Alternative Definition of Propeller Geometry
2.5 Pitch
2.6 Non-dimensional Geometric Parameters
2.7 Mass and Inertia

Chapter 3 PROPELLER THEORY
3.1 Introduction
3.2 Axial Momentum Theory
3.3 Momentum Theory Including Rotation
3.4 Blade Element Theory
3.5 Circulation Theory
3.6 Further Development of the Circulation Theory

Chapter 4 THE PROPELLER IN “OPEN” WATER
4.1 Introduction
4.2 Laws of Similarity
4.3 Dimensional Analysis
4.4 Laws of Similarity in Practice
4.5 Open Water Characteristics
4.6 Methodical Propeller Series
4.7 Alternative Forms of Propeller Coefficients

Chapter 5 THE PROPELLER “BEHIND” THE SHIP
5.1 Introduction
5.2 Wake
5.3 Thrust Deduction
5.4 Relative Rotative Efficiency
5.5 Power Transmission
5.6 Propulsive Efficiency and its Components
5.7 Estimation of Propulsion Factors

Chapter 6 PROPELLER CAVITATION 115
6.1 The Phenomenon of Cavitation
6.2 Cavitation Number
6.3 Types of Propeller Cavitation
6.4 Effects of Cavitation
6.5 Prevention of Cavitation
6.6 Cavitation Criteria
6.7 Pressure Distribution on a Blade Section

Chapter 7 STRENGTH OF PROPELLERS
7.1 Introduction
7.2 Bending Moments due to Thrust and Torque
7.3 Bending Moments due to Centrifugal Force
7.4 Stresses in a Blade Section
7.5 Approximate Methods
7.6 Classification Society Requirements
7.7 Propeller Materials
7.8 Some Additional Considerations

Chapter 8 PROPULSION MODEL EXPERIMENTS
8.1 Introduction
8.2 Resistance Experiments
8.3 Open Water Experiments
8.4 Self-propulsion Experiments
8.5 Wake Measurements
8.6 Cavitation Experiments

Chapter 9 PROPELLER DESIGN
9.1 Propeller Design Approaches
9.2 General Considerations in Propeller Design
9.3 Propeller Design Using Methodical Series Data
9.4 Design of Towing Duty Propellers
9.5 Propeller Design Using Circulation Theory

Chapter 10 SHIP TRIALS AND SERVICE PERFORMANCE
10.1 Introduction
10.2 Dock Trials
10.3 Speed Trials
10.4 Bollard Pull Trials
10.5 Service Performance Analysis

Chapter 11 SOME MISCELLANEOUS TOPICS
11.1 Unsteady Propeller Loading
11.2 Propellers on Inclined Shafts
11.3 Vibration and Noise due to Propellers
11.4 Propulsion in a Seaway
11.5 Propeller Roughness
11.6 Transverse Forces due to Propellers
11.7 Acceleration and Deceleration
11.8 Engine Propeller Matching
11.9 Propeller Manufacture
11.10 Propeller Repair

Chapter 12 UNCONVENTIONAL PROPULSION DEVICES
12.1 Introduction
12.2 Paddle Wheels
12.3 Multiple Propeller Arrangements
12.4 Controllable Pitch Propellers
12.5 Ducted Propellers
12.6 Supercavitating Propellers
12.7 Surface Piercing Propellers
12.8 Contra-rotating Propellers
12.9 Podded and Azimuthing Propellers
12.10 Contra-rotating Pod Propellers
12.11 Tip Modified Propellers
12.12 Cycloidal Propellers
12.13 Waterjet Propulsion
12.14 Energy Saving and Flow Improvement Devices
12.15 Design Approach

APPENDICES
1. Some Properties of Air and Water
2. Aerofoil Sections Used in Marine Propellers
3. Propeller Methodical Series Data
4. Propulsion Factors
5. Propeller Blade Section Pressure Distribution
6. Goldstein Factors
7. Cavitation Buckets
8. Lifting Surface Correction Factors
Review Questions

Miscellaneous Problems

Answers To Problems

References

Index