Yacht Design School – Lesson 4a
Theory & Practice of Developing Excellence in Hull Lines

Revised 07/08/2020 - Copyright 2020

Books To Be Read With This Lesson
Aero-Hydrodynamics of Sailing
by C.A. Marchaj
Theory of Wing Sections by Ira H. Abbott and Albert E. Von Doenhoff (highly optional)
Modern Subsonic Aerodynamics by R.T. Jones (highly optional)
GA Airfoils by Harry Riblett

Minimum New Tools for This Lesson
No new tools needed

What You Will Receive With This Lesson
YDS Lesson Four A Example.3dm
Shining Moon 36 Lines
MacNaughton 48 Lines (Faired with constant angle diagonals)

What You Will Learn In This Lesson
Introduction to the Three “Excellence” Lessons
The Presumed Effect on Performance of Each Line Type
Problems in Judging Each Line Independently
Avoidance of Thinking of Buttock Lines as Suitable Fairing Lines
Avoidance of Thinking of Waterlines as Suitable Fairing Lines
Using Diagonals to End the Confusion
When Optimum Waterlines Would Be Hollow or Convex Forward or Aft
Step by Step Procedure for Developing the Best Lines
Why Diagonals Should Never Have a Hollow Curve
Example of Hull Drawn Without Using Diagonals
Improvement of the Example Hull Using Diagonals to Control the Other Lines
Mention of Lesson Five Model Making for Developing Lines
History of Fairing With Diagonals
Tests for Ideal Diagonal Shape
Examination of the Differences in Developing Planing Hulls
Planing Hulls as an Extreme Case
Bustle Sterns and Immersed Transoms
Evaluating a Hull Surface Using the ShortPath Command
Using the History Toolbar
Bow and Forefoot Shapes for Best Performance

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