Saysurey Parallel Ruler Marine Navigation Tool with Clear Scales Parallel Ruler with Brushed Aluminum Arms Nautical Charts Navigation Tools for Boat Ship Drawing(12 Inch)

This parallel ruler is way too short to do any navigating with it also is poorly made and is loose and move all over

A parallel ruler is made up of two rectangular straight edges connected by two arm joints. The arms allow the two halves of the ruler to move closer or further away while always remaining parallel to each other. To use a parallel ruler for navigation, start by identifying your current position and your intended destination on a nautical chart. Align the edge of the ruler with these two points. Keeping one arm of the ruler fixed, rotate the other arm to “walk” it across the chart. Keep moving one arm at a time until you’ve aligned the ruler with the nearest compass rose. The object is to take the ruler’s edge to the middle of the compass rose without changing the angle. This will help you determine the course to steer.Not just for sailors, parallel rulers help draftsmen, surveyors, cartographers, architects, quilt makers, and artists draw accurate parallel lines. This parallel ruler from Saysurey is a nice tool for anyone who collects maritime or mathematical memorabilia. The clear acrylic material gives this ruler high transparency. The four little round cork pads on the underside of the ruler help it to glide while keeping a steady grip on the surface. The arms are brushed aluminum. There are two knobs on top for you to hold onto. Since the ruler is clear acrylic, I worry that it will get scratched or cracked, so I’m keeping it in the green box that it came in and storing it on a shelf. The only thing that would make this item better is if it came in a plastic case.