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Plank Width Calculator

Calculate hull plank widths for lapstrake or carvel boat building.

Quick Samples
Try these common configurations to get started

Small Dinghy

6 planks on a small hull

Day Sailer

8 planks on a mid-size hull

Cruising Boat

10 planks on a larger hull

Hull Dimensions
Enter your boat's principal dimensions

e.g., inches, mm

e.g., inches, mm

per side

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About This Tool
The Plank Width Calculator is a specialized tool for boat builders using traditional planking methods like lapstrake or carvel. It helps you 'line off' the hull by determining the necessary width of your planks at different stations to ensure they follow a fair, natural curve. By inputting the hull's girth at two stations and the desired number of planks, you can calculate the required plank widths, ensuring a strong, beautiful, and watertight hull.

Key Concepts:

Girth: The measurement along the hull's curved surface from keel to sheer.
Lining Off: The process of marking the plank lines on the hull frames.
Spiling: The process of transferring the shape of a plank from the hull to the stock lumber.
Fair Curve: A smooth, continuous line that is essential for a boat's performance and appearance.
Frequently Asked Questions

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