Trans RINA, Vol 154, Part C1, Intl J Marine Design, Jan - Jun 2012


BELIEVING IN KARMA: THE MEETING OF ART AND SCIENCE IN THE DEVELOPMENT OF THE WORLD’S FASTEST 30 FOOT CANTING KEELBOAT


R G Shaw, Unitec NZ (DOI No: 10.3940/rina.ijmd.2012.c1.11)


SUMMARY


The lack of a complete, recognised methodology for designing racing yachts has resulted in an environment which does not foster innovation, relying instead on engineering techniques which impose limitations on the design process. Designers are also limited to some extent by tradition, as well as being hampered by class and rating rules.


This paper defines a new methodological framework used in the development of the Shaw 9 metre, arguably the world’s fastest 30 foot canting keelboat. It explains the iterative process used, based on Zuber-Skerrit’s action research model, but blending the empirical knowledge obtained through scientific techniques with experiential wisdom and artistic input. It argues that in a field increasingly dominated by mathematical models and computer-based predictions, there remains a powerful role for the “designer’s eye” in creating high-performance yachts.


NOMENCLATURE


ABS American Bureau of Shipping CAD computer-aided drafting CFD computational fluid dynamics CNC computer numerical control Cp prismatic coefficient IMS International Measurement System IOR International Offshore Rule IRC Royal Ocean Racing Club international measurement and rating rule


ISAF International Sailing Federation LCG longitudinal centre of gravity LOA length overall LWL load waterline length PHRF performance handicap rating factor polar computer-generated performance prediction SSANZ Short-handed Sailing Association of New Zealand


TCG transverse centre of gravity VCG vertical centre of gravity VPP velocity prediction program


1. INTRODUCTION


The multifaceted nature of yacht design, informed as it is by theory and practice from various and diverse fields of knowledge, is both challenging and rewarding. However, the range of complex influences and issues required to be worked through to resolve the process into a coherent, successful design has not been well researched and documented. This is partly because, as Killing and Hunter state, “Sailboats surely are unique among objects created by humankind in that they are perceived and even created in one configuration but employed in another” [1] — that


is, they are designed in a upright, static


configuration yet utilised in a wide range of conditions and a dynamic environment.


The designing of yachts has evolved over many centuries ©2012: The Royal Institution of Naval Architects C-27


and is now acknowledged as an iterative process. In the past 50 years the methods of design and development have become heavily influenced by the engineering discipline, which can stifle the influences of art and creativity in the process.


In the past, yacht designers concentrated on evolving traditional, proven hull, deck and appendage shapes. Yacht designers


used a combination of design and


building experience, intuition and their “eye” — i.e. what they thought looked good to them — to develop new designs, drawing subconsciously on a range of types of knowledge. Phillips-Birt describes “the ideal [yacht] designer” as “a magnificent creature who is at once a hydro-dynamist, an aero-dynamist, an engineer, a practical boatbuilder, an experienced seaman under sail, and an artist.” [2]


However, with the development of mathematical computer-based models, including VPPs or generating


polars, many modern designers have begun to rely more on “science” than “art” to define the parameters of their designs. Yet it is noted by Scarponi, Shenoi, Turnock and Conti that “To bear the costs of a close modelling of a sailing yacht, with the purpose of getting accurate VPP predictions, is still far from being an easy task. . . . A numerical approach in terms of Computational Fluid Dynamics can also be regarded as a valuable source of information, but . . . numerical methods can provide just partial responses to designers”. [3]


The lack of a complete, recognised methodology for the design of racing yachts has resulted in an environment which does not foster innovation, relying instead on engineering techniques, which impose limitations on the design process. Designers are also limited to some extent by tradition — following what has gone before — as well as being hampered by class and rating rules such as IOR, IMS and more latterly IRC, and


by safety requirements. These factors combined have meant


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