The Weems and Plath parallel rulers are used to plot direction on nautical charts. The two straightedges are hinged so that they can maintain the same angle. By alternating the moving edge, and securely holding down the nonmoving edge, you can move the rulers about the chart while still maintaining the same angle.
This Parallel Rule is primarily is suitable even for commercial purposes due to its extra long 24 inch acrylic construction, rigid chrome arms and handles.
- Milled acrylic with beveled edges with rigid chrome arms.
- Includes protractor scale.
- Weems and Plath lifetime warranty.