Preliminary Design – Ratios, Coefficients, Feasibility & Midsection Development
Revised 05/27/2020 – Copyright 2020
Minimum Tools for This Lesson if Using Computer Assisted Design
Rhinoceros® (commonly known as Rhino) Version 4.0 or later
What You Will Receive With This Lesson
See drawings from Lesson Two A
Choosing the Speed to Length Ratio
Hull Speed
Choosing Prismatic Coefficient
Choosing the Displacement to Length Ratio
Midsection Development Principles
Plaining Saile and Power Boats
Defining the Midsection – By the Visual Method
Defining the Midsection – Using Prismatic Coefficient and Displacement to Length Ratio
Relating the Midsection and Lines Development
First Trial on Scantlings
First Trial on Ballast
First Trial on Sail Area and Engine Horsepower
Laws of Mechanical Similitude
Useful Proportional Ratios
Appendix A: References and Discussion Points for Prismatic Coefficient
Appendix B: Concept Design Spreadsheet Templates