Weems & Plath 18" Parallel Rule

Size:	457 x 66 x 13 mm

£26⁵⁹ ~~£27⁹⁵~~

VAT included

Delivery and Shipping

We aim to dispatch all orders by the next business day, but we're a small business and sometimes when it's busy it may take a little bit longer. If there's going to be any delays we'll get in touch and keep you up-to-date.

Shipping is free for all orders of £50 or more!

We work with Royal Mail, DPD and DHL to offer the most convenient delivery options to our customers.

Advice

Chris is a Master Mariner and knows a thing or two about seafaring. If you need any help then don't be shy - send us an email or get in touch using the WhatsApp icon.

Extended Returns

Not what you were looking for? No problem. We can accept returns of items in as-sold condition for up to 30 days (maybe a bit longer but don't tell anyone).

Any orders made from 14 November can be returned until the end of January!

Just let us know and we'll sort everything out, including the shipping cost back to us.

Unfortunately this doesn't apply to Print on Demand charts as they are correct at the time of printing.

Of course if there's any faults or damage then let us know and we'll make it right!

Innovation Rooted in Tradition

Durable aluminium parallel rule with protractor scale

The Weems & Plath 18" Aluminium Arm Parallel Rule is a favourite among sailors, offering a reliable and efficient way to plot courses and measure distances on nautical charts. The integrated protractor scale (Captain Field pattern markings) allows you to measure angles when there isn't a convenient compass rose nearby on your chart.

This parallel rule is slightly longer than the best-selling 15" version, making it ideal for use on larger chart tables. It's a popular choice for Royal Navy and Merchant Navy navigators and cadets, as well as anyone who appreciates a longer reach and added versatility.

Features:

18-inch (45.7 cm) length
Brushed aluminium arms
Polished aluminium handles
Milled acrylic with bevelled edges
Integrated protractor scale (Captain Fields Pattern)
Protective plastic sleeve
Limited 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.

Beyond its nautical applications, this parallel rule can also be used for drafting, surveying, and other tasks that require precise parallel lines.