Graph partition

The displacement–length ratio (DLR or D/L ratio) is a calculation used to express how heavy a boat is relative to its waterline length. (Rousmaniere, 1999)

A DLR is calculated by dividing a boat's displacement in long tons (2,240 pounds) by the cube of one one-hundredth of the waterline length (in feet):

$\mathit{D}\mathit{L}\mathit{R}=\frac{\mathit{d}\mathit{i}\mathit{s}\mathit{p}\mathit{l}\mathit{a}\mathit{c}\mathit{e}\mathit{m}\mathit{e}\mathit{n}\mathit{t}(\mathrm{l}\mathrm{b})/2240}{(0.01\times \mathit{L}\mathit{W}\mathit{L}(\mathrm{f}\mathrm{t}){)}^3}.$

The DLR can be used to compare the relative mass of various boats no matter what their length. A DLR less than 200 is indicative of a racing boat, while a DLR greater than 300 or so is indicative of a heavy cruising boat.

References

• Rousmaniere, J, The Annapolis Book of Seamanship Simon & Schuster, New York, New York, Chapter 1: The boat p26-35, 1999. ISBN 0-684-85420-1
• http://www.sailingusa.info/design_winds.htm

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