1. EN400 – Principles of Ship Performance
An Introduction to Naval Architecture
(Alias “Boats”)
Associate Professor Paul H. Miller

2. INTRODUCTION Course Objectives (Why Study Boats?)
Personal Introductions
Name
Major
Service Selection
Syllabus/Course Policy
Lecture #1! - Engineering Fundamentals

3. Some of my projects…

4. ENGINEERING FUNDAMENTALS
Plots, Graphs, and Sketches (1.1)
Plots or Graphs - Generally the most effective format for displaying and conveying the interrelation of experimental variables.
Sketches - Quick and informal method of sharing ideas with others or clarify concepts for yourself. Free body diagrams (FBDs) are an example.

5. ENGINEERING FUNDAMENTALS
Plots and Graphs (1.1)

6. ENGINEERING FUNDAMENTALS
Sketches (1.1) – A Free Body Diagram

7. ENGINEERING FUNDAMENTALS
Plots, Graphs, and Sketches (1.1)
Means of Communicating Ideas Concisely
Axes
X-axis (horizontal (independent variable))
Y-axis (vertical (dependent variable))
Divide major axes into divisions of 1, 2, or 5 times 10 to the nth power
Label with words, symbols, and units
Minor axes should be distributed evenly

8. ENGINEERING FUNDAMENTALS
Area Under and Instantaneous Slope of a Curve (1.3)
Dependent

9. ENGINEERING FUNDAMENTALS
Units (1.4) 
 the unit system used in EN200

10. Engineering Fundamentals
Unit Analysis (1.4.1)
A “fool proof” method of determining the correct units!
Example: Speed x Time = Distance
hour
miles
x 30 min 8
1 hour
60 min x
= 4 miles

11. ENGINEERING FUNDAMENTALS
Significant Figures (1.5)
The number of accurate digits in a number
Example: 2.65 has 3 significant figures
Example: 10 has 1 or 2 , 10.0 has 3
Example: 0.25 has 2 (note 0.25, not .25!)
Multiplication / Division: Use the same # of
significant figures as the number with the least # of significant figures
Example: 20 x = 69
Addition / Subtraction: Use the same # of
decimal places as the number with the least # of decimal places
Example: = 4.8

12. ENGINEERING FUNDAMENTALS
Forces, Moments, and Couples (1.7)
FORCE - a vector quantity (i.e. a magnitude and a direction)
MOMENT – a force times a distance with respect to a given origin (M=FxD)
COUPLE - A special case of moment causing pure rotation and no translation

13. ENGINEERING FUNDAMENTALS
Static Equilibrium 1.7.5
If an object is neither accelerating or decelerating then it is because…
Sum of the forces = 0
Sum of the moments = 0
Why?
F=ma
(This is very important in “hydrostatics”)

14. Hydrostatic Pressure 1.7.6
“Pressure” is the amount of force applied to a given area (p=F/A)
In English units it is pounds/sq. ft. or pounds/sq. in., or “psi”
Air pressure is ~ 15 psi.
At 440 ft below sea level it is ~ 195 psi!

15. Quick Physics Review Static: No acceleration Dynamic: Has acceleration
Question: If a ship follows this path, at a constant speed, is it static or dynamic?

16. ENGINEERING FUNDAMENTALS
The Mathematical First, Second and Third Moments (1.7.7)
These integrals are used in mathematical descriptions of physical problems
Where:
s = some distance
db = some differential property
= Summation

17. ENGINEERING FUNDAMENTALS
The Mathematical First, Second and Third Moments (1.7.7)
In Naval Architecture:
“b” could represent length, area, volume, or mass
“s” is a length or distance
First Moment of Mass 
Second Moment of Area 

18. ENGINEERING FUNDAMENTALS
Weighted Averages (1.7.7)
In Naval Architecture we use the simplified form:
to find the Longitudinal Center of Flotation (LCF), Longitudinal Center of Buoyancy (LCB), Center of Gravity (LCG, TCG, VCG)

19. ENGINEERING FUNDAMENTALS
Translational and Rotational Motion (1.8)
A ship (or plane) has 6 degrees of freedom (DOF)
Three are Translational
Heave (z) (up and down)
Sway (y) (side to side)
Surge (x) (fore and aft)
Three are Rotational
Yaw (z)
Pitch (y)
Roll (x)

20. Bernoulli’s Equation
Along a line of equal energy (a streamline) in a fluid, the above is a constant.
P = pressure
r = fluid density
V = fluid velocity
Z = depth

21. ENGINEERING FUNDAMENTALS
Bernoulli Equation (1.9)
total pressure is constant in a fluid, if:
inviscid flow (no viscosity)
incompressible flow
steady flow
This gives us hydrostatic and hydrodynamic pressure. These are the water loads on the vessel.

22. Pressure Prediction
Vertical pressure supports the vessel (lift versus weight)
Horizontal pressure is thrust and drag
These are the same as an aircraft!