Weems & Plath 138 18″ Aluminum Parallel Rule

The 18” Aluminum Arm Parallel Ruler features aluminum arms and handles. The aluminum parallel ruler is manufactured to a 1/4″ thickness and 18” length. The high-quality construction of the aluminum parallel ruler is backed with a lifetime warranty. 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.