The 18-inch Weems & Plath Aluminum Arm Parallel Ruler features aluminum arms and handles. This parallel ruler is manufactured to a 1/4-inch thickness and 18-inch length.
An essential item in any proper navigation kit, the aluminum parallel ruler is used to plot direction on your nautical chart.
The aluminum parallel ruler is, essentially, comprised of two straight-edges hinged so that they maintain the same angle. By alternating the moving edge, and securely holding down the non-moving edge, you can move the aluminum parallel ruler about the chart while still maintaining the same angle.
The high-quality construction of the Weems & Plath aluminum parallel ruler is backed with a lifetime warranty.