The Bi-rola Rule is a rugged plotter that is used by professional navigators because it is quick and easy to use. Patented vertical and horizontal rolling motion simplifies course and plotting calculations.

• Unique radial arm allows you to automatically include compass corrections in course plotting
• Roller body has protractor markings and nautical mile scale
• Radial arm has Loran interpolator scales and 200 milimeter rule
• When radial arm and body are used jointly, the bi-rola rule becomes a 17 inch (440mm) divider
• Speed/time/distance table included
• Protective, durable vinyl pouch included
• Easy to follow instructions included