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A slide-rule reference to the marks, signs and rules of Europe's inland waterways.

Limited lifetime warranty from Weems & Plath on the movement, for as long as you own the instrument. View the warranty terms (PDF)
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Shipped insured and fully tracked directly from the manufacturer's warehouse in Denmark or England. Free delivery in the Netherlands from € 75.
14-day right of withdrawal under European law, with manufacturer warranty handled by us. Contact us first and we send you a return note.
The ROADrule CEVNI identifies navigation aids and markers as prescribed by the European Code for Inland Waterways, turning complex information into something quick to read.
Slide, read, decide
Move the window to the mark you see and read its meaning through the lens: 38 navigation-aid definitions and 12 rules of the road.
A handy companion on rivers and canals and a great study aid.
Key features
- CEVNI code
- 38 definitions
- 12 rules of the road
- Magnifier
Specifications
| Feature | Detail |
|---|---|
| Brand | Weems & Plath |
| Type | Navigation aid slide rule (CEVNI) |
| Dimensions | 407 × 133 mm (16 × 5¼ in) |
| Content | 38 definitions, 12 rules of the road |
| Material | Plastic with magnifier |
| Warranty | Weems & Plath Limited Lifetime Warranty |
| Weems & Plath item number | 291 |
| EAN | 0721002004369 |
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Explore our navigation aids and parallel rules and plotters, or see the full range on our Weems & Plath brand page.
Founded in Annapolis in 1928 by navigator Captain Philip Van Horn Weems, Weems & Plath remains a byword for dependable instruments. Order with confidence from Shipsclocks.com.
Frequently asked questions
ROADrule or LIGHTrule?
ROADrule covers marks and rules; LIGHTrule covers vessel lights and shapes.
- Material
- Plastic







