Tony Butt - Surf Science: An Introduction to Waves for Surfing

Surf Science

An Introduction to Waves for Surfing

TONY BUTT

Have you ever wondered where surfing waves come from, what makes every wave different, why some peel perfectly and others just close out; why, some days, the waves come in sets and other days they dont, and how the tides, the wind and the shape of the sea floor affect the waves for surfing?

If you have, this book is for you. Now in its third edition, Surf Science is the first book to talk in depth about the science of waves from a surfers point of view. It fills the gap between surfing books and waves textbooks, and will help you learn how to predict surf. You dont need a scientific background to read it just curiosity and a fascination for waves.

What the critics said about earlier editions of Surf Science:

one of the most sophisticated surfing books ever produced a must for any surfer (Ben Marcus, Surfers Journal, May 2003)

Tony Butt is a surf forecasting guru. If he doesnt know it, it isnt worth knowing (Surf Europe, Issue 22, 2003)

So who would benefit from this book? Well, its hard to think of a surfer who wouldnt. (The Surfers Path, Issue 33, 2002)

an excellent resource for surfers who want a simple understanding of the hows and whys of wave creation and surf conditions (hisurfadvisory.com, October 2004)

jam-packed with many helpful graphs, diagrams, photographs (Longboard Magazine, February 2005)

clearly reaches out to both surfers and those interested in the surf great color graphics and color photos (David F. Narr, Associate Professor, College of Marine Science, University of South Florida, Oceanography, vol. 18, no. 2, June 2005)

Tony Butt has a PhD in Physical Oceanography and worked with the Coastal Processes Research Group at Plymouth University for some ten years. He is a big-wave surfer and lives for most of the year in a forgotten corner of north-west Spain.

For my sister, Tina, 19472012

If youve ever wondered where the waves come from, what makes every wave different and what factors affect the behaviour of a surf spot, youll like this book. You dont need a scientific background to read it. In fact, you dont even need to be a surfer; all you need is a love for the ocean and a sense of curiosity.

It has now been ten years since I wrote the original version of this book. In this, the third edition, I have completely revised the text, revised the diagrams and photos, removed two chapters and added two new ones. So this edition is actually quite different from the last two.

The original idea behind Surf Science was to fill the gap between surfing books and textbooks. Youll find general surfing books with a basic oceanography section, easy to read but sometimes inaccurate; or advanced textbooks, much more complete but full of equations. However, you won't find much in between. With Surf Science, I have tried to steer somewhere between these two extremes, making the descriptions as complete as possible using familiar examples and light-hearted analogies, but without getting into any of the heavy maths. Of course, you can only go so far with that, so if you want to dig a bit deeper there are references to more advanced books.

The first seven chapters describe the life of a wave (or, more precisely, a packet of energy that briefly manifests itself as a wave), from before its birth in an oceanic storm to its final dissipation on the shore. Each of these chapters describes a different process and may be read on its own, but is probably better read as part of a complete sequence. Each of the next four chapters is a self-contained description of a phenomenon affecting the waves for surfing, and the last three chapters contain some useful knowledge on wave forecasting.

Most of the information in the original version of this book is still relevant, and so a lot of the changes I have made are just improvements in the descriptions. However, wave forecasting has changed quite a bit in the last ten years; so I have expanded and updated that section. You will also find the chapter on tides considerably longer than before, now doing a bit more than just scratching the surface of what is a very complicated subject. If you feel that the tides chapter is too advanced, you can leave it out without affecting the rest of the book. Finally, I have removed the chapters on wave climate and coastal morphology. These subjects are now covered in my book The Surfers Guide to Waves, Coasts and Climates.

Tony Butt, Spain, 2014

1 Introduction

The paradox of impossible knowledge

Looks like its going southerly, pointed out the surfer, as he gazed up at the clouds and sniffed the air.

Yeah, said the other, Theres a warm front on the chart associated with a 985 sitting a few hundred miles west of Shannon.

The K2 buoy is already showing ten feet at fourteen seconds, said the first. I reckon itll pick up on the push of the tide what is it anyway, springs or neaps?

Its a five point eight, said the second, after consulting a strange list of numbers screwed up in his back pocket.

To the innocent bystander, this sounds more like scientific terminology than the jargon associated with some sport or leisure activity. Yet this is the sort of language surfers throughout the world you and I use every day of our lives. You see, without realizing it, most surfers are also scientists. Surfers who have spent many years riding different waves in different parts of the world have, without any special effort, become meteorologists, oceanographers, geographers, linguists and cultural experts. Through an obsession with tapping the oceans energy to propel them along for a few seconds, surfers end up acquiring a large amount of peripheral information. All that watching, discussing, waiting and thinking gives us an insatiable thirst for knowledge, typical of scientists rather than sportspeople. This unique facet of surfing gives it a richness rarely found in other activities.

If you are a surfer, no doubt you will have asked yourself, while gazing out at the ocean or sitting in the line-up waiting for the next set, questions like these:

Why is every wave different?

Why are some waves more powerful than others?

Why do some peel nicely and some just close out?

Why, some days, do the waves come in sets of six, and other days in sets of three?

How would this place work on a north, or indeed a south, swell?

Why didnt that low produce any surf?

Where did that swell come from?

What are waves anyway?

And doubtless some of us have asked many more obscure questions. Some of these are readily answerable; others take some thinking about. Yet others a surprisingly large number are much more difficult or impossible to answer even at top oceanographic research level. There are some concepts that surfers know intimately, in a qualitative way, that are barely acknowledged by the scientific community, typically through lack of demand for practical application.

For example, the groupiness of a swell has been studied by some coastal engineers for the design of coastal structures. But exhaustive details of the length of time between sets, the number of waves in a set, whether each set has the same number of waves in it, or how the wave heights are distributed throughout the set, are not required for such a study. For surfing, however, these details can be crucial, especially on a big day.

Likewise, the answers to some questions that surfers are constantly wondering about, have been sitting there in the scientific literature for years. A little knowledge about wave periods, for example, can explain the difference between a strong, powerful new swell and a weak, gutless old one.