Yacht Design School – Lesson 15

Resistance & Powering

Revised  04/16/2019 – Copyright 2019


Recommended Reading for This Lesson

                No additional books required with this lesson.


Tools for This Lesson

No additional tools are required.


What You Will Learn In This Lesson

                Introduction to Resistance

                General Theory of Resistance

                Resistance in Sailing Vessels

                Resistance in Displacement Power Vessels

                Resistance in Planing & Other High Speed Forms

Introduction to Powering

                Horsepower – Displacement Speeds

                Horsepower – Planing Speeds

                Lift, Trim, and Powering in Non-Stepped and Stepped Planing Powerboats

                                Calculation of lift and trim for planing hulls.

                                Refining Shape for Reasonable Motion

                                Designing to Avoid Chine Walking in Waves

                                Weight Reduction

                                Effect of Deadrise Angles on Lift

                                Effect of Center of Gravity on Trim and Lift

                                Over Reliance on Strakes

                                Interference of Marketing Personnel in Naval Architectural Decisions

                                Special Considerations in Designing Stepped Planing Hulls

                Special Design Considerations Appropriate to Planing Speeds

                Propeller Size and Pitch

                Shaft Size

                Offset Versus Centerline Propellers

                Conventional Stuffing Boxes Versus Shaft Seals and Dripless Packing

                Diesel and Gasoline Engine Types

                Electric Drives

                Rational Matching of Vessel Use and Power

                Understanding the Basic Math of Internal Combustion Engines

                Engine Beds

                Rowing Craft Power

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