Engineering:Displacement–length ratio
From HandWiki
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) (in en). The Speed and Power of Ships: A Manual of Marine Propulsion. John Wiley & Sons. p. 99. https://books.google.com/books?id=Xy86AQAAMAAJ.[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]
- [math]\displaystyle{ \mathit{DLR} = \frac{\mathit{displacement}(\mathrm{lb}) ~/~ 2240} {(0.01 \times \mathit{LWL}(\mathrm{ft}))^3} }[/math]
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
References
- ↑ Rousmaniere, John (October 1999). The Annapolis book of seamanship. ISBN 0-684-85420-1.
- ↑ Eric W., Sponberg. "The Design Ratios". https://www.ericwsponberg.com/wp-content/uploads/2021/09/THE-DESIGN-RATIOS.pdf.
- ↑ Paris, Jay E. (31 May 2018). "Comparing Design Ratios" (in en-us). https://www.sailmagazine.com/boats/comparing-design-ratios. Retrieved 9 July 2020.
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