The performance of any sailing craft largely depends on the power of the available sail how the rig uses the wind and turns it into a useful driving force. But sail forces are determined by a multitude of factors, including wind speed, sail area, sail shape, sail setting, the hull, angle of heel, wind gradient, and steadiness of the wind.

From wind tunnel tests which he has conducted, Tony Marchaj describes how these factors affect sail power and why certain rigs are superior in power and efficiency to others. The tests also indicate where improvements in efficiency may be made, particularly when freed from the constraints imposed by the arbitrary limitations of the racing rules.

Professor Marchaj compares a number of different types of rig Bermudan, lateen, sprit, gunter, dipping lug and Polynesian crab claw and concludes that the Bermudan rig, which dominates the contemporary sailing scene for racing and cruising, is by no means the best available.

This major work makes a significant contribution to our understanding of the factors which contribute to an efficient sailing rig, and is a landmark in modern thinking on the subject.

"There can't be a yacht designer around who doesn't know Marchaj's Sailing Theory and Practice: this is the modern version of a classic." Yachting World

"By a master of wind tunnel and test tank research . . . a unique publication." Multihull International

"A classic." Royal Naval Sailing Association

"Exceptional value . . . should be on the bookshelf of very serious amateur and professional sailor." Nautical Magazine

"This is one of the most authoritative works around." Yachting World

Selected Contents

Part 1: Rating Formulae and Speed Performance

-Speed and size
-Seakindliness and seaworthiness
-Speed performance factors
-How fast is fast?
-The drive towards ultimate speed

Part 2: Aerodynamics of Sails

-How and why an aerodynamic force is produced
-Distribution of pressure over sails
-Effects and measurement of aerodynamic forces
-Aerodynamic drag of the sail
-Apparent wind structure
-Sail camber and sail shape
-Sail power of various rigs
-The effect of wind gradient
-Sail-hull interference
-Wing sails
-Sail interaction
-Centre of effort
-Cut, set and defects of sails

Part 3: Steady and Unsteady Wind

-The significance of barometric depressions
-True wind structure
-Local winds
-Microbursts
-Pumping a legitimate technique?
-Rolling downwind
-Katzmary effect --This text refers to an out of print or unavailable edition of this title.

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