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.[1]
DLR was first published in Taylor, David W. (1910). The Speed and Power of Ships: A Manual of Marine Propulsion. John Wiley & Sons. p. 99.[2]
It 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):[3]
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.
| Displacement | DLR |
|---|---|
| ultralight | under 90 |
| light | 90 to 180 |
| moderate | 180 to 270 |
| heavy | 270 to 360 |
| ultraheavy | 360 and up |
See also
editReferences
edit- ^ Rousmaniere, John (October 1999). The Annapolis book of seamanship. Simon and Schuster. ISBN 0-684-85420-1.
- ^ Eric W., Sponberg. "The Design Ratios" (PDF). Sponberg Yacht Design Inc.
- ^ Paris, Jay E. (31 May 2018). "Comparing Design Ratios". Sail Magazine. Retrieved 9 July 2020.
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