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Waterplane Area Calculator

Analyze your boat's stability and trim by calculating its waterplane area.

Quick Samples
Try these common configurations to get started

30ft Cruising Sailboat

Fine entry, fuller stern

40ft Planing Powerboat

Wide beam for stability at speed

22ft Trailer Sailer

Narrow waterline for low drag

Hull Dimensions
Enter your boat's principal dimensions

feet

feet

Range: 0.65 - 0.95

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About This Tool
The Waterplane Area Calculator is a fundamental tool for naval architects and serious boat designers. It calculates the area of the hull at the waterline, which is critical for determining initial stability, load-carrying capacity (TPI), and how the boat trims (LCF). Understanding the characteristics of your waterplane is the first step towards analyzing and predicting a boat's performance on the water.

Key Concepts:

Waterplane Area: The 2D area of the hull at the waterline.
Waterplane Coefficient (Cwp): A measure of the 'fullness' or shape of the waterplane.
Tons Per Inch (TPI): The weight required to sink the boat by one inch.
Center of Flotation (LCF): The pivot point around which the boat trims.
Frequently Asked Questions

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