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Some people like to sail
Some people like to sail fast
Some people like to get the windshifts right as well
This book is written for those who like to sail fast and well
This is a book about sailing faster. It is also a book for beginners, because so much of its content is new. In any new environment there are few experts.
During the past two decades, there has been a revolution in the way some Australian skiff-class designers and sailors have thought about, designed, built, and sailed their boats. These classes are free from all restrictions and so create an environment in which new materials and technology can be tried, developed and optimised. The combined effect of these changes has been to achieve a spectacular increase in performance. This book is about the new ideas which have lead to these greater speeds and the faster sailing techniques which have been developed to achieve them.
In suitable conditions some high performance boats can now sail around a course at an average speed faster than the wind. The new ideas and handling techniques which have been developed around these boats are proving faster when applied to conventional boats also. The 'spin-off can help everybody sail faster.
The history of sailing is a story of two periods. There was a long period of thouands of years when nobodoy sailed for fun and throughout which the core ideas about sailing changed very little. This has been followed by a short period of about three hundred years, when increasing numbers of people have sailed for fun. During this time, a number of very important changes have taken place, of which the most recent is probably the most important of all. As yet, it is little understood.
Sailing began many thousands of years ago, when some innovative primitive held up a skin to 'catch the wind' and found that he could in this way escape the labour of paddling whenever 'the wind was fair'. When the wind was not 'fair' he accepted that he still had to paddle. So this sort of 'sailing' was simply a part of paddling and was thought of as hard work. Fun it was not.
As the centuries rolled by, sail-powered ships were developed for fishing, for trade, and for military might. The skin held up to catch the wind was replaced by woven sails, which on the bigger craft were always rigged on yards. These ships proved reasonably efficient for downwind and crosswind sailing but their performance when it was necessary to sail against the wind was dreadfully slow. At their best, when sailing crosswind or downwind, the best that could be expected was about one tenth of this, so sailing to windward remained something to be avoided by all means possible.
Occasionally there were exceptions. Wherever the waterways were narrow and shipmasters had no option but to sail against the wind for much of the time, smaller boats of different kinds evolved. The beautifully shaped Arab dhows, with their lateen rigs, originated in the Red Sea area. In the narrow Bristol Channel in English water, which is regularly swept by westerly gales from the Atlantic, a breed of fore and aft rigged cutters evolved. Both these boats possessed legendary seaworthiness, a reputation due primarily to their very good windward-sailing ability. Another of these exceptions came from the East India. In 1661, John Evelyn recorded, 'I sailed this morning on the Thames with His Majesty (Charles II) in one of his yachts...vessels not known among us until the East India Company presented that curious piece to the King, being very excellent sailing vessels...' the sport of 'Yachting' had been born. This was the beginning of sailing for fun.
During the subsequent three hundred years of pleasure sailing, our expectations of performance have changed profoundly.
Introduction
Some who helped
Units, bows and noses
PART ONE Wind
Chapter One. The Racing Helmsman's Wind
1.1 Where to sail?
1.2 Kiel
1.3 Marstrand
1.4 Keppel bay
1.5 Lake Garda
1.6 Rio de Janeiro
1.7 The different possibilities
Chapter Two. The Gradient Wind
2.1 The wind's driving force
2.2 Circulation
2.3 Ups and downs
2.4 Fires in the sky
Chapter Three. The Two Surface Winds
3.1 The two surface winds
3.2 Light airs
3.3 Breezes
3.4 Wind recording instruments
3.5 Factors which shape the wind
Chapter Four. Light Airs
4.1 Steady light air
4.2 Thermal excitation
4.3 Thermal excitation over water
4.4 Thermal excitation over dry land
4.5 Isolated thermal
4.6 Isolated thermals over large areas
4.7 The cellular mechanism
4.8 Unsteady air - the cellular pattern
4.9 Roll mechanism
4.10 Pulsing air - the transverse roll
4.11 Oscillating air - the longitudinal roll
4.12 Ribboning air -the boosted longitudinal roll
4.13 Shore effects
4.14 Pattern size
4.15 Practicalities
4.16 What to look for
4.17 Sydney Harbour - Australian Intervarsity championships
4.18 Tallinn - Baltic pre-olympic regatta 1978
Chapter Five. The Breeze over a Cool Surface
5.1 The onset of turbulence
5.2 The change of wind force on sails
5.3 The shape of the breeze
5.4 The gust mechanism
5.5 The fan
5.6 The effect of depth of the boundary layer
Chapter Six. Friction and Wind-Wave Patterns
6.1 Order - but where from?
6.2 Waves in the air - the friction mechanism
6.3 Oscillating surface waves
6.4 Regular or random
6.5 Transverse and other rolls
Chapter Seven. Heat and Thermal Patterns
7.1 Surface heat in calm conditions
7.2 Surface heat in light airs
7.3 Surface heat in breeze
7.4 Gusts plus surface heat
7.5 Wind-waves plus surface heat
7.6 Big wind-waves plus heat - the harmonic patterns
7.7 Small wind-waves - plus surface heat
7.8 The convergent/divergent pattern
7.9 The channelling winds
7.10 The two cell sizes
7.11 'Look for the speckled area'
7.12 The wandering breeze
7.13 Chilled air
Chapter Eight. Winds near Clouds
8.1 The significant clouds
8.2 Frontal clouds
8.3 Ball clouds
8.4 Cumulus clouds - non raining
8.5 Raining clouds
Chapter Nine. Winds near Shores
9.1 Standing points
9.2 The sea breeze mechanism
9.3 The quadrant effect
9.4 Refinements
9.5 The funnelling winds
9.6 Shoreline factors
9.7 The chilled wind situation
9.8 The land breezes
Chapter Ten. Wind Appraisal and the Stability Index
10.1 The parts of the puzzle
10.2 The kind of wind
10.3 The probable pattern
10.4 The stability index
Chapter Eleven. Race preparation
11.1 Principles and priorities
11.2 Preparation - overview
11.3 The water's waves and currents
11.4 Pre-regatta preparation
11.5 Pre-race preparation
11.6 Pre-start preparation
11.7 The winds
11.8 Pre-regatta preparation
11.9 Pre-race preparation
11.10 Pre-start preparation
11.11 In unsteady winds
11.12 In the steadier winds
11.13 In the quicker oscillations
11.14 In deep boundary layers
Chapter Twelve. Sailing the Wind Patterns
12.1 The four groups
12.2 Sailing the unsteady winds
12.3 Sailing the wind-waves
12.4 Sailing through fronts
12.5 Sailing the cloud winds
12.6 The effects on wind of 'open' barriers
PART TWO. Water
Chapter Thirteen. Waves
13.1 The four wave systems
13.2 Wave motion
13.3 Regular waves
13.4 Chaotic waves
13.5 Swell
13.6 Standing waves
Chapter Fourteen. Depth and the Warm Surface Layer
14.1 Depth
14.2 The warm surface layer
Chapter Fifteen. Currents and Tidal Stream
15.1 Drive force
15.2 Friction effects and the velocity gradient
15.3 Flows through channels
15.4 Momentum effects
15.5 Flow over bars
15.6 Curves and eddies
15.7 Wind shear effects
15.8 Current and wave size
Preface to Part Three
PART THREE. The Boat
Introduction
Chapter Sixteen. The Quest for Speed
16.1 Forces on a sailboat when sailing to windward
16.2 To sail faster
16.3 Changes of wind speed
16.4 The two wind speed ranges
16.5 Change of size
16.6 The emergence of ratios and weight
16.7 Historical performance limitations
16.8 Moving the crew to windward
16.9 The reduction of weight
16.10 The Eighteens and the third step
16.11 The dominance of ratios
16.13 Downwind faster
16.14 Some unexpected observations
16.15 The dynamics of catamarans and sailboards
16.16 The application of ratios and the future
16.17 Different paths - same destination
Chapter Seventeen. Sails
17.1 The starting point
17.2 Wings
17.3 The boundary layer
17.4 Sails behind masts
17.5 The separation bubble
17.6 Sails without masts
17.7 Super-critical and sub-critical flow
17.8 Dreams and realities
17.9 Modern rig development
17.10 Wingmasts - early development
17.11 The modern wingmast
Chapter Eighteen. Rigs
18.1 The four rig groups
18.2 Group one - gaff rigs
18.3 Group two - early Bermudan rigs
18.4 Group three - the experimental years
18.5 Objects and dynamics
18.6 Modern rigs
Chapter Nineteen. Foils
19.1 The foils - the centreboard, keel and rudder
19.2 Laminar flow sections
19.3 Surface texture
19.4 Modern foil development
19.5 Control at higher speeds
19.6 The drag of surface-piercing foils in wake
19.7 Centreboard area, point of sailing, wind speed and experience
19.8 Cambered centreboards
19.9 The rudder blade
19.10 Summary
Chapter Twenty. Hulls
20.1 Experimental background
The motion of a dinghy hull
20.2 Summary
20.3 Skin friction
20.4 Form drag
20.5 Induced drag and leeway
20.6 Rudder deflection drag
Wave making drag
20.7 The three modes
20.8 Displacement sailing
20.9 The forced mode
20.10 Breakout and planing
20.11 The fourth mode
Drag in waves
20.12 Drag in regular waves - upwind and downwind
20.13 Drag in regular waves - crosswind
20.14 Drag in chaotic waves
20.15 Drag in swell
20.16 Concepts of mode sailing
PART FOUR. Handling
Chapter Twenty. One ft Scope
21.1 Relevant conditions
21.2 High performance and other sailboats
21.3 Physical principles and administrative restrictions
Chapter Twenty Two. Handling to Windward
22.1 Conventional and high performance handling
22.2 Sailing for speed, comfort and survival
22.3 The three handling regimes
22.4 In light airs
22.5 In moderate breezes - the vital changes
22.6 Sail trim techniques
22.7 Effects of fluctuations and gusts on techniques
22.8 Handling in moderate breezes
22.9 In stronger breezes - the new factors
22.10 The trims for most power and least drag
22.11 Sail trim in 12-16 knots
22.12 Sail trim in 17-25 knots
22.13 Handling in stronger breezes
22.14 In rough air
22.15 Survival
22.16 To windward in waves
22.17 The effects of waves on performance
22.18 In waves and light airs
22.19 In waves and breeze - sail trim in 6 to 14 knots
22.20 In waves and breeze - sail trim in 15 to 25 knots
22.21 Handling in regular waves
22.22 Handling in chaotic waves
22.23 Handing in swell
22.24 Handling in waves and rough air
Chapter Twenty Three. Kinetics
23.1 Introduction
23.2 Negative kinetics - the part power pause
23.3 Positive kinetics
23.4 Impulse
23.5 Energy recovery
23.6 Overtrimming (pumping)
23.7 Combined impulse and pumping
23.8 Surging
23.9 Other possible techniques
23.10 Summary
Chapter Twenty Four. Sailing Crosswind
24.1 Crosswind sailing
24.2 Reaching dynamics
24.3 The design wind zones
24.4 The balance position
24.5 Steering for balance
24.6 Control at high speeds
24.7 In light air and flat water
24.8 In light air and waves
24.9 In moderate breeze and flat water
24.10 In moderate air and waves
24.11 Sailtrim crosswind in stronger breezes
24.12 Arc 1 - flat water and windward planing
24.13 Arc 1 - rough water
24.14 Arc 2
24.15 Arc 3 - zone A and flat water
24.16 Arc 3 - zone A and rough water
24.17 Arc 3 - zone В
24.18 Introduction to Arc 3 - zone С
24.19 Arc 3 - zone С in steady wind and flat water
24.20 Arc 3 - zone С in gusts and channelling
24.21 Arc 3 - zone С in waves
Chapter Twenty Five. Sailing Downwind
25.1 Sailing downwind - the principles and the performance factors
25.2 The fleeting dynamics of wind and wave
25.3 Rig characteristics an the properties of the delta planform
25.4 Hull characteristics
25.5 Handling in light airs and flat water
25.6 Two mode sailing
25.7 Handling in light air and waves
25.8 Downwind in breeze
25.9 Handling in blocking waves
25.10 Handling in surfing waves
25.11 Handling in mixed waves
25.12 Handling in chaotic waves
25.13 Handling in swell
25.14 Sailing the shifts
25.15 Handling in gusts
25.16 Practical handling downwind
Postscript
Appendix. Faster Sailing with Foilers
1. The unfinished foiler
2. 49er T-foiler (moth configuration)
3. 49er motor foiler
4. 49er sail foiler, Mkl, Jan to July '09
5. 49er sail foiler, Mk2, Longlegs
Index