Parallel Rule — Captain Fields 12″

Essential Chartwork Tool • Precision by Weems & Plath

A dependable set of parallel rules is a cornerstone of traditional navigation—and an essential backup when electronic systems fail. The Captain Fields 12″ Parallel Rule is engineered for accurate, repeatable chartwork, offering the balance, rigidity, and clear markings navigators rely on for plotting courses and transferring bearings with confidence.

Built to Weems & Plath’s standards for marine instruments, this rule is equally suited to daily chart table use or inclusion in a contingency navigation kit.

🧭 Why Navigators Rely on It

• Consistent accuracy — maintain true parallels while “walking” bearings across a chart

• Confidence without electronics — dependable manual plotting when GPS or power is unavailable

• Practical size — 12″ length handles most chart formats without excess bulk

• Built to last — durable aluminium construction for life at sea

⚙️ Construction & Features

• 📏 12″ (305 mm) working length — ideal for routine passage planning and fixes

• 🛠️ Brushed aluminium arms — lightweight, rigid, and corrosion resistant

• ✋ Polished aluminium handle — smooth control and precise placement

• 🔺 Precision-milled, bevelled edges — clean alignment against chart lines

• 📐 Integrated protractor scale — quick reference for checking bearings and angles

The smooth action and stable geometry make repeated transfers accurate and fatigue-free.

📐 Specifications

🎯 Ideal For

• ⛵ Sailors & offshore cruisers — essential backup navigation tool

• 🧭 Navigation students & instructors — clear, reliable chartwork practice

• 📚 Passage planning & coastal plotting

• 🧰 Emergency navigation kits — lightweight, dependable, no power required

The Captain Fields 12″ Parallel Rule delivers straightforward precision—nothing more, nothing less. Accurate, durable, and ready when you need it most.

Add a trusted manual plotting tool to your chart table and navigate with confidence.