Principles of Yacht Design

Principles of Yacht Design has established itself as the standard book on the subject for practising designers, naval architecture students, discerning boat owners as well as the boatbuilding industry as a whole. The fifth edition is completely revised and expanded. It examines every aspect of the process of yacht and powerboat design. The new edition includes new findings from recent research in aero and hydrodynamics, as well as covering the most recent changes to building standards. The authors have used a newly built 41-foot performance cruiser to demonstrate the practical application of yacht design theory. This new edition includes photos of the building process and detailed explanations.

Lars Larsson is a naval architect and owner of the International School of Yacht Design. He was Professor of Hydrodynamics at Chalmers University in Gothenberg, Sweden.

PREFACE TO THE FIFTH EDITION LIST OF SYMBOLS INTRODUCTION 1 DESIGN METHODOLOGY The design spiral Computer-aided design (CAD) 2 PRELIMINARY CONSIDERATIONS Choice of boat-type Intended use Main dimensions Cost Checklist of considerations Checklist for the YD-41 3 HULL GEOMETRY Definitions Lines drawing Tools Work plan Computer-aided design of hulls 4 HYDROSTATICS AND STABILITY Calculation of areas Wetted surface Displacement Centre of buoyancy Water plane area Transverse and longitudinal stability at small angles Transverse stability at large angles of heel Curve of static stability Rolling Influence of waves on the righting moment Stability statistics Assessment of seaworthiness 5 HULL DESIGN Forces and moments on a sailing yacht Resistance components Viscous resistance: basic concepts Frictional resistance Viscous pressure resistance Roughness Wave resistance: basic concepts Wave and residuary resistance Heel resistance Added resistance in waves Other seakeeping aspects Hull statistics 6 KEEL AND RUDDER DESIGN Flow around a wing Definition of the keel planform Classical wing theory Tip shape Lift and induced resistance of the yacht Advanced planform design Canting keels Evaluation of some planform concepts Definition of the section Three useful NACA sections Influence of shape on section characteristics Some practical conclusions regarding section shape Influence of deviations from the theoretical section shape Advanced section design Statistics on keel and rudder area The YD-41 7 SAIL AND RIG DESIGN Flow around sails Planform Sail camber Mast interference Means for reducing mast disturbances Streamlining A practical model for sail and rig aerodynamics Sail statistics 8 BALANCE Effect of heel Good balance Centre of effort of the underwater body Centre of effort of the sails Lead Rudder balance 9 PROPELLER AND ENGINE Resistance in calm and rough weather Propeller characteristics Design of an optimum propeller Performance of the non-optimum propeller Check of blade area Propeller resistance 10 HIGH SPEED HYDRODYNAMICS Planing Deadrise Forces on a planing hull Spray rails, stepped bottoms and transom flaps Dynamic stability Alternative propulsion devices An example 11 RIG CONSTRUCTION Definitions and scope of the standard Forces on the shrouds Forces on the stays Comparison between wire and rod Transverse mast stiffness Longitudinal mast stiffness Fractional mast top Boom Spreaders Holes in the mast The YD-41 rig 12 HULL CONSTRUCTION Concepts in structural mechanics Global loads Local hydrostatic loads Local hydrodynamic loads Transverse load distribution Local deformations Forces from the keel Forces from grounding Forces from the rudder Summary of loadings 13 MATERIALS Glass reinforcement Wet laminates Fatigue Exotic laminates Sandwich Typical sandwich buckling Sandwich bending Sandwich in practice Final remarks 14 SCANTLING DETERMINATION Structure of the ISO Standard Basic laminate Design loads for the bottom Design loads for the topsides Design loads for the decks, superstructures and bulkheads Design loads for the internals Longitudinal impact distribution factor Area reduction factor Panel calculation Stiffener calculation Spade rudder stock Chainplates and keelbolts Sandwich construction The YD-41 scantlings 15 LAYOUT Generic space requirements Accommodation Deck layout 16 DESIGN EVALUATION Non-dimensional parameters The Velocity Prediction Program (VPP) Towing tank testing Wind tunnel testing Computational Fluid Dynamics (CFD) APPENDIX 1: Main particulars of the YD-41 APPENDIX 2: Weight calculation APPENDIX 3: STIX calculation REFERENCES INDEX