surf boards 32

for Bachelor of Engineering (Mechanical), Sydney University 1974
This was a fascinating research project involving
# riding waves with an instrumented surfboard (a pitot tube and pressure gauge for speed measurement) - measured speeds ranged from 5 to 10 m/s
# observing surfboard riding and taking speed measurements from the shore (similar results)
# reviewing ocean wave theory - deep ocean waves, solitary (cnoidal) waves and breaking waves
# developing an early (punch card!) computer model of a shoaling breaking wave
# reviewing and adapting theory for planing water craft - including stability problems (porpoising) and lift/drag/trim data from seaplane research.
# designing, constructing and operating an experiment which generated a standing wave in a flume tank. The resulting wave was about 200mm high (flume 1.2m wide, flow rate 0.37 cumecs)
# constructing model surfboards and experimenting with them on the standing wave.
# (unsuccessfully) trying to model a human spring mass system to dampen the instability of the models (this was essentially a 2D flow - it turns out that a 3D flow would probably have eliminated the instability - see the paper by Hornung and Killen).
# recommending some design changes for surfboards: sharp trailing edges and a stepped front to eliminate the strong tendency of the convex front of a surfboard to nosedive (I later built such a surfboard - although it performed as expected on a wave its non-planing drag was high and this made it much more difficult to paddle than a conventional surfboard and this made it impractical)Poerhouse surfing wave

Updates

# 17 Feb 04: As part of its Sports Exhibition, the Powerhouse Museum in Sydney has built a superb interactive surfing display with a 300mm high tubing wave, based on Peter Killen's work. Here is a picture of the display. Click on the picture for a movie clip (3Mb).
# Reaper Cheat - inflatable rash vest. A clever design that featured on The New Inventors in 2004. The Sydney agent is: Canoe Sports, 2/6 Taronga Place, Mona Vale NSW 4922, Ph: (02)99794911
# 26 Feb 05: Swansea University Research into Fins and Surfboards (SURFS) research group
# 30 Jun 05 New Scientist: Surf's up, down at the swimming pool
# ASR “Amalgamates Solutions and Research” - [Design of] Multi-purpose artificial surfing reefs + Nature ($): Creating the perfect wave (p997)
# 21 Aug 08 BBC: Bournemouth makes waves with surf plan.



I have scanned most of the (typewritten!) pages of my thesis and created a 400K PDF file. To save space I have not included several of the photos so save them as images from this page if you need them. No copyright but acknowledge and/or a link would be appreciated.

Here is the table of contents:
CONTENTS
Acknowledgements.
Notation.
Introduction.
Previous Work.
Chapter l Theory.
Principles of surfboard riding.
Ocean wave theory.
Typical Sydney waves.
Planing hull theory.
Chapter2 Hydrodynamics of surfing.
Initial case,surfing deep water waves.
Hydrodynamics of surfing across a breaking wave. -
Chapter 3 Experimental Work.
Field experiments;
Measurement of wave and peeling velocities.
Surfboard speed measurement.
Performance of the equipment in the surf.
Results.
Hydrodynamics laboratory experiments;
Creating a standing wave.
Design of the equipment.
Initial results.
Chapter 4 Stability of surfboards.
General stability.
Porpoising;
Theory.
Discussion of the theory.
Stability of an actual surfboard.
Human response - the effects on stability.
Effects of the curved free surface.
Chapter 5 Conclusions
Effects of waves on planing craft
Some design suggestions for surfboards
A concluding note
References
Appendix
I. Deep water wave computer program.(Fortran!)
II Adaption of NACA model test data
III Wave profile measurement