How to use this book.
Many readers may think that section 2 is more than is required to understand a yacht. However reference is made in section 3 to the many aspects of “theory” which are essential in order to follow the text. It is really best to browse section 2 before tackling section 3 and then go back to look at section 2 carefully as the need arises.
This book can be downloaded using a modern printer to appear like the original on A4 paper. The aberrations in the presentation of the text on the screen are the result of the change to html that has to be made to upload to the web.
Click on any chapter to open it.
Mathematical equations and units. The triangle of forces. Relative motion. Framed structures. Centre of gravity. Centre of volume. Centre of area. Second moment of area. The concept of pressure. Flotation. Stability of floating vessels. Metacentre and metacentric height. Potential energy and kinetic energy. Pressure energy.
The structure of water when it is at rest. The motion of water near to the surface resulting from wind blowing over it. Pressure variation in water at rest.
Air as a gas. The structure of a gas. The action of wind on a lake.
Introduction. Forms of motion of surface vessels. Skin drag. Resistance to motion resulting from wave making. The idea of a critical speed.
Flow patterns and aerodynamic lift. The effect of an aerofoil on the upstream flow. Pressure distribution round an aerofoil. Separation. Lift and drag. Aerofoil data. The effect of aspect ratio. Aerofoils at high angles of attack.
Tacking. Apparent wind. Leeway. Vector diagram for the beating yacht. Angle of attack of the main sail. Forces on sails
The Hele-Shaw equipment. The shape of sails. The single sail in the Hele-Shaw rig. The Bermuda rig in the Hele-Shaw equipment.
The polar performance diagram. The swing rig. Combined force on a swing rig. The sailing diagrams. Implications of the polar diagram.
Vortices and breakaway. Practical testing. Photographs.
The sheeting mechanism. The winch. The requirements of the rig. Sheeting the fore sail. Sheeting the main sail. Sheeting the sails together. Changing to smaller rigs. Selecting a drum size. Position of the sheeting eye on the fore deck.
Sailing diagrams for boom angles from 0° to 90°. Sailing diagrams for reaching and running.
The standing rigging used for the Bermuda rig. The sail mountings. The swing rig.
The design of sails for model yachts. The sail plan. The profiles. The main sail. The fore sail.
Introduction. The section of the fin. Surface finish. Choice of section area of fin. Shape of fin.
The directional control of a yacht. The wing/stabiliser system. The fin and rudder system.
Changing course. Design of the rudder.
Low drag profile for round bulbs. Bulbs for yachts with draught restrictions. Surface finish.
Strength. Flotation. Stability. Leeway and turning. The shape of the hull.
The sailing rig. The hull and the rig. Sailing in light winds. The model yacht as a whole. Design guidelines for model yachts. Post script