# Displacement–length ratio

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):

${\displaystyle {\mathit {DLR}}={\frac {{\mathit {displacement}}(\mathrm {lb} )~/~2240}{(0.01\times {\mathit {LWL}}(\mathrm {ft} ))^{3}}}.}$

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
• https://web.archive.org/web/20101127054902/http://sailingusa.info/design_winds.htm