Weems & Plath 24" Parallel Rule

The Weems & Plath 24" Parallel Rule is a robust and reliable navigation tool designed for professional and commercial use.

This extra-long parallel rule is ideal for plotting courses and measuring distances on large nautical charts. Crafted from durable acrylic with rigid chrome arms and handles, it offers exceptional stability and accuracy for demanding navigational tasks. Absolutely perfect for Merchant Navy cadets and Superyacht course students undertaking college and SQA navigation/chartwork exams.

The integrated protractor scale (Captain Field pattern markings) allows for precise measurement of angles and bearings, making it even more versatile for complex navigational calculations.

Features:

• 24-inch (61 cm) length
• Brushed aluminium arms
• Polished aluminium handles
• Milled acrylic with bevelled edges
• Integrated protractor scale
• Protective plastic sleeve
• Lifetime warranty

How to Use a Parallel Rule

A parallel rule consists of two straight edges joined by hinges, allowing them to move closer or further apart while remaining parallel. To use it, place one edge along your desired course or bearing, then hold it securely while moving the other edge to a new position on the chart. This allows you to transfer lines and angles accurately, making it an essential tool for navigation and chartwork.

A History of Precision

Parallel rules have been used by navigators for centuries to draw parallel lines on charts. The earliest versions date back to the 16th century, and the design was further refined in the 19th century by Captain William Andrew Field, who added a protractor scale and compass points for easier bearing measurement.

About Weems & Plath

Founded in 1928 by Lieutenant Commander Philip Van Horn Weems, Weems & Plath has a long and distinguished history of providing sailors with high-quality nautical instruments and navigational tools. From the Weems Plotter to the Second Setting Watch, their innovations have helped shape the world of navigation.

Today, Weems & Plath continues to uphold its tradition of craftsmanship and precision, offering a wide range of navigational tools and instruments for sailors of all levels.