Douglas Square Protractor — 5″ / 125 mm

📐 Precision Angles • Compact Control • A Chartwork Classic

The Douglas Square Protractor 5″ (125 mm) is a precision plotting instrument designed for clear, accurate angle measurement on nautical charts and maps. Compact, transparent, and easy to handle, it’s a trusted choice for skippers, students, and instructors who want reliable results without cluttering the chart table.

Made to professional standards by Douglas, this square protractor reflects the enduring value of traditional navigation tools—simple geometry done right.

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🧭 Why the Douglas 5″ Square Protractor Belongs in Your Kit

📏 Compact 125 mm Size — Control Where It Counts

• 5″ (125 mm) format offers excellent control for fine, localised chart work

• Ideal for confined chart tables, exam desks, and detailed plotting

• Easy to store, quick to deploy, comfortable for extended use

This size is a favourite for accuracy-focused work and training environments.

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📐 Clear, Accurate Angle Measurement

• Precisely marked degree graduations for fast, confident readings

• Square edges support clean alignment with meridians and chart features

• Ideal for measuring and plotting bearings, courses, and intersections

When angles matter, clarity matters.

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👁️ Transparent Acrylic — See the Chart, Not the Tool

• Clear construction keeps chart detail fully visible beneath

• Reduces parallax and alignment errors

• Helps place angles exactly where they belong

Nothing obscures your work—precision stays front and centre.

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🛠️ Durable & Chart-Friendly

• Made from rigid, high-quality acrylic that resists flexing and warping

• Smooth, polished edges glide over charts without snagging

• Built for repeated classroom and real-world use

A dependable tool you’ll use again and again.

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⚓ A Core Instrument of Traditional Navigation

Square protractors remain essential for:

• Teaching chartwork fundamentals

• Manual plotting and cross-checking electronic navigation

• Passage planning and exam work

• Maintaining disciplined seamanship skills

Compact tools like this one excel at precise, controlled plotting.

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📐 Specifications

• 📏 Size: 5″ / 125 mm

• 📐 Type: Square protractor

• 🧭 Use: Angle measurement, bearing plotting, chart navigation

• 🛠️ Material: Clear acrylic

• ⚓ Application: Nautical charts, training, professional chartwork

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🎯 Who This Is For

• ⚓ Skippers & sailors — accurate manual plotting on board or ashore

• 🧭 Navigation students — ideal for exams and training

• 📘 Instructors & schools — durable, classroom-ready equipment

• 🗺️ Traditional navigators — disciplined chartwork with confidence

• 🎁 Maritime gift buyers — a practical, purposeful navigation tool

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⭐ Why Choose Douglas?

Douglas navigation instruments are valued for clarity, accuracy, and reliability—tools designed to support both learning and professional practice without unnecessary complexity.

The 5″ Square Protractor is a perfect example: compact, precise, and dependable.

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Measure with confidence—every degree counts

Add the Douglas Square Protractor 5″ (125 mm) to your chart kit and enjoy clean, accurate plotting wherever your navigation takes place.
Add to cart and keep your chartwork sharp and exact.