| Name and Model Number | Froude Displacement Rule |
| Country of Origin | England |
| Date of Manufacture | ~1902 |
| Front Scales | X3/X3 X/X Displacement, Length,K, Speed |
| Back Scales | X2/X2 X/X Scale, Knots, Ft/m |
| Scale Length | 62cm |
| Type of Rule | Slide Rule |
| Construction | Box, closed frame, brass blade cursor |
| Area of Use | Other |
| Comment | Used for ship hull designase leave blank. |
| Rarity | RR-RRR |
| Donor | Collection of Peter Fox |
| Match Number | 50 |
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| RR | = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| RRR | = Very rare -- only very few known to collectors; may take several years before one comes up for sale. |
| RRRR | = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale. |