PSModel a look inside

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Introduction

Quick Start

Quick Series
Facts

PSModel
Program

Data Input

Data Output

Importing a
Data file into
MS Excel

Main Menu

Main Screen

Printing
Graphs
and Data

Screen Colors
and Fonts

Screen
Graphs

Shortcuts

Working
with Data

Testing:

Test Sheet

Examples

19' Ski Boat

34' Sailboat

41' Utility Boat

Technical

Blade Area
Ratio

Calculating
the Cavitation
Number

Horsepower
Losses

Hull Speed

Kt Breakdown

Propeller
Geometry

Propeller Law

Wake Factors

Glossary

References

Hull Speed: 

Hull speed is the approximate speed of a boat, operating in the displacement mode, above which horsepower requirements start to rise rapidly for relatively small increases in boat speed.  For example, a boat with a hull speed of 7.2 knots may require an additional 4 HP to increase speed from 5.5 to 6.5 knots, but above hull speed it may take an additional 20 HP to increase speed from 7.5 to 8.5 knots.

The hull speed of a boat is given by the following formulas:

MPH = 1.542 x (Waterline Length In Feet)1/2

Knots = 1.34 x (Waterline Length In Feet)1/2

Hull speed is generally characterized by a large bow wave followed by a wave trough that approaches the stern of the vessel.