Wind power developments for sailing boats into headwinds
Ancient maritime history tells of the development of the lateen sail, which allowed wind-powered vessels to sail at a 30-degree angle into a headwind. It is the basis of windmill driven vessels being able to sail directly into a headwind. During the 1970s, an inventor and mechanical engineer from New Zealand named Jim Bates built a windmill powered catamaran capable of sailing directly into a headwind at eight knots, preceding Canadian physics professor Brad Blackford by a decade.
Introduction
New Zealand based mechanical engineer Jim Bates and his daughter Jennifer designed and built his windmill powered catamaran vessel named “Tango”. Many years later, the concept was proven during a sailboat race at Halifax, Canada when physics professor Brad Blackford sailed a windmill powered boat directly into a headwind to win the race. British sailboat enthusiast Peter Worsley built a scale model windmill powered vessel to prove in a water tank, to illustrate that the forward thrust of a windmill-driven propeller can actually exceed the rearward drag of the windmill. Worsley built several small-scale windmill-driven vessels capable of sailing directly into a headwind. He discovered that using a slower-turning, horizontal-axis wind turbine that delivered high levels of torque at low RPM to be well suited for driving a submerged propeller. Worsley developed and tested a small-scale windmill powered on a small inland lake using readily available wind. His initiative provides a basis for other enthusiasts to build and test their own small-scale versions of wind-powered vessels capable of using wind energy to sail directly into a headwind.
By Harry Valentine
Early Experiences
Jim Bates provided some insight into performance issues that he encountered when he sailed his windmill-driven catamaran at 8 to 9 knots directly into
a headwind blowing between 20 and 30 knots. During powerful wind conditions that caused waves, Bates found it necessary to restrict speed so as to prevent damage to the vessel’s hull. The combination of propeller generating forward thrust below the water surface and the windmill producing rearward aerodynamic drag far above the water surface when sailing directly into powerful headwinds, caused weight to transfer from the bow area to the stern area.
Based on the experiences of Jim Bates, Peter Worsley built and tested many types of wind turbines intended for vessel propulsion. Unlike power generation wind turbines, he set blade angles at a maximum of 45-degrees to reduce wind turbine drag and generate sufficient thrust to overcome that drag. Using smaller blade angles than 3-bladed power generation turbines has allowed Worsley to reduce turbine rotational speed and resulting blade induced wake and turbulence. He was able to install additional blades to his turbine, with the option of installing twin rotors on the same driveshaft.
THE REPORT | DEC 2023 | ISSUE 106 | 113
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144
